Huberman LabHow to Improve Brain Health & Offset Neurodegeneration | Dr. Gary Steinberg
EVERY SPOKEN WORD
150 min read · 30,143 words- 0:00 – 1:44
Dr. Gary Steinberg
- AHAndrew Huberman
(uptempo music) Welcome to the Huberman Lab Podcast, where we discuss science and science-based tools for everyday life. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. My guest today is Dr. Gary Steinberg. Dr. Gary Steinberg is a medical doctor, PhD, professor of neurosurgery, neurosciences, and neurology at Stanford University School of Medicine. He is a world expert in what is called the cerebrovascular architecture of our brain, which is a scientific term explaining how blood flow to the brain supplies oxygen and critical nutrients through our neurons, our nerve cells, as well as playing a critical role in removing waste products from our brain in order for our brain to function normally. During today's discussion, he explains in very clear terms how blood flow to the brain occurs and how disruptions in blood flow in things like stroke and aneurysm impact brain functioning. We also discuss concussions and TBI, or traumatic brain injuries, which unfortunately are very common, and what can be done to treat concussion and traumatic brain injury. Dr. Steinberg also shares with us recent findings from his laboratory and clinic, revealing how stem cells can be used to recover function in the human brain and spinal cord after things like concussion, TBI, stroke, and other disruptions to the cerebrovascular architecture. And he shares with us the science-supported tools, that is protocols, that any of us can use to improve the health and functioning of our brains. So if you or somebody that you know has experienced concussion or traumatic brain injury, stroke, or aneurysm, today's discussion is sure to include vital information for you. And for those fortunate enough to not have experienced those conditions, today's discussion will also review the latest science and protocols for improving brain
- 1:44 – 6:16
Sponsors: Eight Sleep, ROKA & AeroPress; Subscribe on YouTube, Spotify & Apple
- AHAndrew Huberman
health. Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero-cost-to-consumer information about science and science-related tools to the general public. In keeping with that theme, I'd like to thank the sponsors of today's podcast. Our first sponsor is Eight Sleep. Eight Sleep makes smart mattress covers with cooling, heating, and sleep-tracking capacity. Now, I've spoken many times before on this podcast about the fact that sleep is the critical foundation for mental health, physical health, and performance. Now, one of the key things to getting the best possible night's sleep is to control the temperature of your sleeping environment, and that's because in order to fall and stay deeply asleep, your body temperature actually needs to drop by about one to three degrees. And in order to wake up feeling refreshed and alert, your body temperature actually has to increase by about one to three degrees. Eight Sleep mattress covers make it extremely easy to control the temperature of your sleeping environment, and thereby to control your core body temperature so that you fall and stay deeply asleep and wake up feeling your absolute best. I've been sleeping on an Eight Sleep mattress cover for about three years now, and it has completely transformed the quality of my sleep for the better. Eight Sleep recently launched their newest generation of pod cover, the Pod 4 Ultra. The Pod 4 cover has improved cooling and heating capacity, higher-fidelity sleep-tracking technology, and the Pod 4 cover has snoring detection that will automatically lift your head a few degrees to improve airflow and stop your snoring. This is really important. Snoring is associated with something called sleep apnea, and sleep apnea is known to disrupt brain health and body health in a number of ways. Put differently, being able to breathe clearly throughout the night is essential for not only feeling rested when you wake up, but also for brain health and body health. If you'd like to try an Eight Sleep mattress cover, you can go to EightSleep.com/Huberman to save $350 off their Pod 4 Ultra. Eight Sleep currently ships to the USA, Canada, UK, select countries in the EU, and Australia. Again, that's EightSleep.com/Huberman. Today's episode is also brought to us by ROKA. ROKA makes eyeglasses and sunglasses that are of the absolute highest quality. Now, I've spent a lifetime working on the biology of the visual system, and I can tell you that your visual system has to contend with an enormous number of different challenges in order for you to be able to see clearly. ROKA understands this and has developed their eyeglasses and sunglasses so that regardless of the conditions you're in, you always see with the utmost clarity. ROKA eyeglasses and sunglasses were initially designed for use in sport, in particular things like running and cycling. Now, as a consequence, ROKA frames are extremely lightweight, so much so that most of the time you don't even remember that they're on your face. They're also designed so that they don't slip off if you get sweaty. Now, even though they were initially designed for performance in sport, they now have many different frames and styles, all of which can be used in sport but also when out to dinner, at work, essentially any time and in any setting. If you'd like to try ROKA glasses, you can go to ROKA, that's ROKA.com, and enter the code Huberman to get 20% off. Again, that's ROKA.com and enter the code Huberman to get 20% off. Today's episode is also brought to us by AeroPress. AeroPress is like a French press, but a French press that always brews the perfect cup of coffee, meaning no bitterness and excellent taste. AeroPress achieves this because it uses a very short contact time between the hot water and the coffee, and that short contact time also means that you can brew an excellent cup of coffee very quickly. The whole thing takes only about three minutes. I started using an AeroPress over 10 years ago, and I learned about it from a guy named Alan Adler, who's a former Stanford engineer who's also an inventor. He developed things like the Aerobie Frisbee. In any event, I'm a big fan of Adler inventions, and when I heard he developed a coffee maker, the AeroPress, I tried it, and I found that indeed it makes the best possible tasting cup of coffee. It's also extremely small and portable, so I started using it in the laboratory, when I travel on the road, and also at home. And I'm not alone in my love of the AeroPress coffee maker. With over 55,000 five-star reviews, AeroPress is the best-reviewed coffee press in the world. If you'd like to try AeroPress, you can go to AeroPress.com/Huberman to get 20% off. AeroPress currently ships in the USA, Canada, and to over 60 other countries around the world. Again, that's AeroPress.com/Huberman. I usually mention this at the end of episodes, but if you're learning from and/or enjoying the Huberman Lab Podcast, please click the subscribe button on YouTube. And if you listen to the podcast on Spotify or Apple, make sure you click the follow tab on Spotify and/or Apple. And on both Spotify and Apple, you can also leave us up to a five-star review. And now for my discussion with Dr. Gary Steinberg.Dr.
- 6:16 – 10:25
Stroke, Hemorrhage & Blood Clot
- AHAndrew Huberman
Gary Steinberg, welcome.
- GSGary Steinberg
Thank you, Andrew, pleasure to be here.
- AHAndrew Huberman
I have a lot of questions, I know people are interested in keeping their brains healthy and sadly things happen to the brain, um, sometimes as a consequence of aging, sometimes as a consequence of certain activities. Maybe you could just explain for us right off the bat, what is a stroke? What is an aneurysm? What is a hemorrhage? Where do these terms overlap? How are they different? Obviously none of us want these things, um, and we will talk about w- ways to prevent them and your ways of treating them as well of course, but just to start off, maybe we can just lay down the nomenclature.
- GSGary Steinberg
Sure, so a stroke is like a heart attack of the brain, uh, it involves disruption of blood flow to the brain either in the form of a blocked vessel or less likely a hemorrhage. About 87% of strokes are due to, uh, a clot, either forming in the brain artery itself or forming, uh, closer to the heart, in the heart or in the carotid artery and dislodging and blocking blood flow to the brain. About 13% are caused by a hemorrhage, bursting of a blood vessel, and that results in lack of oxygen and glucose being delivered to the brain cells and that ultimately causes death of tissue and disruption of bodily functions, neurologic function, that's what a stroke is.
- AHAndrew Huberman
How do we know if we have clots residing in our body that could be dislodged? Um, I know that some people when they fly wear, wear compression socks, um, I know that some people have genetic mutations that affect clotting, I'll raise my hand here and, uh, I'll do a disclosure, I did some genetic testing, I am a heterozygote for, um, factor V Leiden which is a clotting factor. Um, heterozygote folks means I have one mutant copy so fortunately I don't suffer from excessive bleeding or clotting but there are lifestyle factors that can exacerbate a, an existing, um, mutation like that. People are homozygous mutants for factor V Leiden of course at much greater risk for, um, clotting and bleeding. Um, so I just disclosed a lot, um, maybe you could comment on some of the clotting factors and lifestyle factors that impact clotting, but how would somebody know if they're, like, they've got a clot that could potentially go to their brain?
- GSGary Steinberg
Sure, well, you might not know, in many cases you don't know, uh, and that's the problem. You can have, uh, a predisposition as you say due to, uh, certain genes that are mutated or, uh, represented that predispose to, to clots and those clots can occur on the arterial side or the venous side. The arterial side is what, uh, generally causes a stroke, an ischemic stroke. Uh, on the venous side you can sometimes, uh, have problems, uh, when you talk about flying, um, not moving your legs, developing clots in your legs, wearing compression boots, that's on the venous side and that can cause, uh, something like a, uh, deep vein thrombosis, uh, whi- which is not good because it can travel to the lung and cause a pulmonary embolus, that generally on the venous side does not go to the brain.
- AHAndrew Huberman
Oh good, in my case that-
- GSGary Steinberg
So you're o-
- AHAndrew Huberman
... that feels fortunate. Yeah.
- GSGary Steinberg
Exactly. Uh, you can develop some venous problems in the brain which can cause a venous tri- type stroke, that's much less common and the way that causes a stroke is not lack of blood flow being delivered to the brain but by having a clot in an important vein the blood can't get out of the brain, it backs up and causes swelling or edema, uh, uh, but that's much less common. Uh, generally we talk about strokes as being, uh, arterial in nature, um, and, you know, either that, either blockage of a blood vessel or bursting o- of a vessel.
- 10:25 – 16:19
Blood Clots & Risk Factors, Medications, Smoking, Cholesterol
- GSGary Steinberg
- AHAndrew Huberman
What are some things that impact clotting and/or excessive bleeding? Um, my understanding is these factor V Leiden mutations are one example, the other is, um, let's say somebody takes say a b- blood thinning, um, agent like baby aspirin or, um, I'm told and I, I'll have to check this I'm sure people will say in the YouTube comments that if you take lots and lots of say fish oil or things like that you can become more of a bleeder, some are, uh, people out there are hemophiliacs and then my understanding is also that certain forms of oral contraception for women can increase, uh, the rates of bleeding. Um, so tell me if I'm wrong about any of those and if any of those things predispose people to more stroke or hemorrhage.
- GSGary Steinberg
Sure, so, um, different kinds of drugs, um, thin the blood and they, um, can predispose you to having a larger hemorrhage, uh, than you would if something, uh, bursts or if you, uh, fall and have some traumatic injury to your brain or anywhere in the body. Uh, in general they don't cause a hemorrhage because they're fairly safe but, uh if there's, uh, as I say some, uh, it's some in- interruption, um, to the, to the body, um, like a bruise, um, it would be a much worse, um, type of bleed. Uh, so aspirin is a type of antiplatelet agent that thins the blood, there are many types of antiplatelet agents and they're very, very, uh, useful for treating people who have, uh, a pr- a predisposition to develop clots because they thin the blood. Anticoagulants are another type, uh, they're, th- they're, uh, called, uh, they're known as Coumadin, warfarin, Eliquis, there's lots of, lots of new agents, um, and, uh, they're often taken, uh, orally or can be given intravenously. Uh, heparin's another one, uh, again they thin the blood so they would, uh, put someone at somewhat increased risk for hemorrhage.Um, then as far as oral contraceptives, if you go back to the 1970s when the, uh, oral contraceptives were first generation were coming out, uh, it turns out... And they were heavily estrogen, um, uh, dominated, uh, rather than progesterone. Um, they did, and they still to some extent increased the risk of developing clots. So women back in the '70s who took oral contraceptives and smoked had a very, very high incidence of developing, uh, clots and, uh, and ischemic strokes and clots elsewhere in the body. The newer generations, uh, are, are much safer in terms of dev- developing clots. But for my patients, uh, many of whom have had strokes or are at risk for stroke, we recommend that the women do not take oral a- uh, contraceptives, that they use some other form. Uh, IUD for instance may have a little bit of, uh, progesterone which is released locally but, uh, doesn't cause a lar- large increase in estrogens or, or progesterone systemically. So we still believe that the oral contraceptives, uh, increase the risk somewhat, not the way it did, uh, for first generation. And then there are other modifiable factors besides the genetic ones. So smoking is a very, uh, high risk factor for developing, uh, clots, um, which can lead to strokes, heart attacks, peripheral vascular disease. Um, high lipids is another. So when people have high bad cholesterol, LDL, it's recommended, uh, that if they can't reduce it with diet that they take a statin. Um, the statins are very, very effective in lowering the bad cholesterol, preventing strokes and heart attack. Interestingly, the statins have also been shown to be highly beneficial for the bl- for the blood vessel integrity even if you don't have high LDL.
- AHAndrew Huberman
Interesting.
- GSGary Steinberg
So they have other beneficial properties. So again, for my patients, I often recommend they take a statin even if they don't have high cholesterol.
- AHAndrew Huberman
Interesting.
- GSGary Steinberg
And then hypertension is another, uh, risk factor for, for developing, uh, clots and, and arterial disease.
- AHAndrew Huberman
When you say that smoking dramatically increases the risk of stroke, is that because of nicotine per se? Is it the, uh, vasoconstriction and blood pressure elevation that comes from nicotine itself or is there something about smoking, maybe even vaping, I, I don't know, that, um, the contaminants, the other chemicals, um, in cigarettes or vape chemicals that increases the stroke risk or is it nicotine itself?
- GSGary Steinberg
It's not just nicotine. Nicotine is one of the factors but it's the other, uh, um, products that are produced by, by smoking that, that can have an effect.
- AHAndrew Huberman
So given that so many fewer at least Americans, and I think worldwide, um, people are smoking less, uh, are we seeing less stroke?
- GSGary Steinberg
Yes. The, the incidence of stroke is actually decreasing.
- AHAndrew Huberman
Mm-hmm.
- GSGary Steinberg
Um, it may be in part due to decreased smoking but it also is in part due to, uh, other modifiable factors. So hypertension is, um, uh, much better, uh, treated now than it used to be. People take better care of themselves in terms of other lifestyle factors so people, uh, exercise more. There's a lower incidence in some subgroups of, uh, obesity. Those are risk factors also for, for, for developing strokes and, a- as well as heart attack.
- 16:19 – 23:27
Heart & Brain Health; Neurosurgery & Brain Function
- AHAndrew Huberman
What is the relationship between heart health and brain health as it relates to stroke? Uh, I would imagine that anything that's good for our heart is probably good for our brain, um, given the enormous amounts of blood and glucose that the, uh, the brain requires to function normally.
- GSGary Steinberg
Yeah. The, the... It's, it's a good point. In general, uh, the things that are good for the heart are good for the brain. There, there are differences between the heart and the brain but, uh, they, they both, uh, depend very much on blood flow. The brain's unique though because the brain represents only 2% of the body weight yet it draws 15% of the total blood flow and remarkably it consumes 20% of the body's oxygen.
- AHAndrew Huberman
Mm-hmm. Amazing, yeah.
- GSGary Steinberg
So the brain... I still think the brain is the most important organ. Uh, not the heart, not the kidneys but I'm biased, of course.
- AHAndrew Huberman
Yeah, you've spent some time in, in, uh, in the landscape of the brain. Yeah, it's, it's clear that, um, of all the tissues in the body if you had to pick one tissue to remove one, you know, cubic millimeter of that tissue that your brain and probably the neural retina would be your, your least, uh, favorite, um, choice just given the deficits that can result.
- GSGary Steinberg
Right, and of, of course the brain also is what makes us human.
- AHAndrew Huberman
Right. Speaking of which, if we take a little departure into, uh, neurosurgery itself, your, your specialty, um, of all the years of, of doing brain surgery, um, can you recall maybe one of the most incredible moments or days, um, that allowed for some insight into how the brain works by virtue of let's say stimulating a given brain area or removing a given brain area or, or something of that sort? I, I ask this because, um, you know, so very few of us will ever have the opportunity to do what you do, and if I were here talking to an astronaut, by the way I consider neurosurgeons the astronauts of neuroscience, um, if I were sitting here with an astronaut I'd say, "You know, tell me something interesting about being in space that I wouldn't know from looking at pictures or videos of it."What is an example of maybe one of the more, um, profound, um, insight-stimulating moments, um, from doing-
- GSGary Steinberg
Yeah.
- AHAndrew Huberman
... brain surgery?
- GSGary Steinberg
There, there, I mean, every patient is different, so I'm al- always learning and that, that's why, uh, yeah, I still enjoy it, that it's a challenge, uh, and you have to think quickly. Um, uh, it's not a r- uh, it's not simply mechanical, but for instance, a couple weeks ago, uh, I had a patient who had a vascular malformation which was located, uh, we thought, right in her speech area. So in order to operate safely, uh, first we did a, what's called a functional MR scan before surgery, and that gives us some idea of where the speech area is. We can map it out on an MR scan, and the way it's mapped out is, um, we have the patient, uh, awake, uh, talk to us when they do the scan, and because there's a coupling between blood flow and, and the neuro- neuronal activity, uh, when the speech area, the language area is stimulated by talking, uh, there's increased blood flow to that area and we can see that on an MR scan. That's how the MR scan works. So we had some idea that this was very close, if not in the speech area, but the most accurate way of determining that is to operate on the patient with her awake. So we took, what we did was we sedate the patient. We don't put a tube down and induce general anesthesia. We numb up the scalp, we take off a piece of bone after cutting the scalp, open the membrane covering the brain called the dura, and then we allow the patient to wake up more from the sedation, and then what I did on this particular patient was to use a, uh, tiny stimulator, a little probe, and I can stimulate areas of her cortex with her awake and see if the stimulation impairs her ability to speak or understand language. And quite surprisingly, there, uh, was no activity in the corridor that I chose. Sometimes when we see, uh, an area that is involved with speech that's eloquent, we have to choose a different pathway to get to the underlying vascular problem. And so that's what we did in this case, and, um, she talked to us the entire case. She told us about her daughter, uh, who, uh, was, uh, very involved in, um, debate and all of her successes while we were operating, while I was taking out this vascular malformation, uh, under 20 magnification with very special instruments. I use a laser now, which has a diameter of the fiber optic cable. Uh, the laser, uh, tip is 0.5 millimeters, so that, I think, is the gentlest way. Other times I've been surprised, um, uh, about brain function is, uh, operating deep in the brain is a part of the brain called the brain stem, which you know well. It's a small area that connects the thalamus. Those are the signals coming from the cortex, go through the thalamus to get down to the face, arm, and leg to move the muscles, and all the sensory information which comes from the arms and legs and face goes through the brain stem up to the thalamus and then to the cortex. In this area, although it's very small, are contained, uh, very closely packed fiber tracts and nuclei. Those are the cell bodies of very important neurons. And when I trained back in the '80s, we never operated in that area because we couldn't do it safely. With developments in computer technology and imaging and anesthesia, we can now find safe corridors to get into the brain stem and sometimes we stimulate for other pathways, not language, but other pathways, and I'm continually amazed. Um, this last week, I took out, um, two vascular malformations, um, and they're not big. I mean, they measure between 8 millimeters and a centimeter, but they can wreak havoc in the brain stem because it's such high-priced real estate and these had bled, but I found a safe corridor to go through. I took it out and I'm amazed th- that you hardly set the patients back in some cases because in the past, we would have clobbered the patients doing that.
- AHAndrew Huberman
Amazing. Yeah, it's, uh, remarkable to me how much can be done w- now with imaging, so visualizing the brain and being able to target a specific location,
- 23:27 – 28:13
Current Technology & Neurosurgery, Minimally Invasive Techniques
- AHAndrew Huberman
and you mentioned fiber o- optic cables. I've also heard of things like the Gamma Knife and lasers. So how much of neurosurgery nowadays is actually burrowing down through the brain to a given location to stimulate or remove tissue versus, um, you know, using these laser or fiber optic approaches to sort of triangulate and get to something without having to basically drill down through the brain?
- GSGary Steinberg
Right. Uh, neurosurgery is becoming much less invasive, and this is something that I really tried to push when I was chair o- of the department for 25 years at Stanford. Um, so minimally invasive techniques include operating through the vessels, right? So now my... I don't do this myself, but my colleagues, some of whom are neurosurgeons, some are interventional radiologists, they can go through the groin in the femoral artery or through the radial artery. They can thread a catheter backwards...
- AHAndrew Huberman
Into the brain.
- GSGary Steinberg
From the groin, they can go up into the aorta, then up into the carotid artery. From there, they can go up into the brain arteries, the middle cerebral artery, and they can treat-... some of the, uh, hemorrhagic problems like aneurysms by deploying thrombogenic coils there or new devices. They can pull clots out if there's an acute stroke from a clot in an artery in the brain.
- AHAndrew Huberman
Wow.
- GSGary Steinberg
It r- it's really r- it's really quite impressive. Um, then we've, we and others have developed techniques to use focused radiation, um, on the brain and that's called radiosurgery. So examples of that are Gamma Knife. Um, CyberKnife was invented at Stanford by one of my colleagues actually and this uses, uh, beams of radiation. Gamma Knife uses a cobalt source, multiple, uh, sources of cobalt. The CyberKnife uses x-rays. Uh, when I started, I was very involved with using cyclotron-generated heavy particles like helium and proton, and they can be focused. And the advantage of this is you don't have to open the skull, you focus it on a very small area and you can eliminate, um, vascular malformations called arteriovenous malformations, tumors. You can even use it for some pain conditions like trigeminal neuralgia. It's not risk-free because even though radiation is n- is- doesn't require (laughs) opening the skull, it's still the form of energy that's damaging. That- that's how it works. It causes, for the AVMs, it gradually clots off the blood vessels, but it's much easier and much safer than some of the invasive techniques that we use. We operate now through tiny openings even when we do open surgery. When I trained, we used to shave the whole head. We would open a huge area of the- of the skull. Now, we operate through tiny ar- very small areas. When I take out vascular malformations, uh, in the brain stem, for instance, uh, I sometimes operate through openings in the side of the brain stem that are two to three millimeters.
- AHAndrew Huberman
Wow.
- GSGary Steinberg
Um, another form of non-invasive, uh, uh, treatment f- that neurosurgeons use is called focused ultrasound. Again, it's, uh, uh, you don't have to open the skull. It focuses, uh, sound waves, um, on areas of the brain. We're using that to treat, uh, essential tremor-
- AHAndrew Huberman
Mm-hmm.
- GSGary Steinberg
... or, um, uh, Parkinson's disease. Um, it's starting to be used for treating tumors. So these are all a- advances that, um, were not present when I- when I trained. Another way of treating, uh, minimally invasive, although it still requires a hole in the head, is to put in an electrode and stimulate the brain. So that, uh, was first used for treating Parkinson's disease, very effective for medically intractable Parkinson's. It's used to treat chronic pain. Recently, it was shown to be beneficial, uh, for epilepsy. In fact, the two major trials, prospective randomized trials that were done, uh, were led by, uh, physicians, uh, neurologists at Stanford and showed the benefit of, um, uh, stimulation of the brain to- to treat, uh, very difficult, um, epilepsy. So this, I think, is gonna be the future is minima- more and more minimally invasive. In fact, we're using some of these techniques to even treat, um, psychiatric disorders-
- AHAndrew Huberman
Hmm.
- GSGary Steinberg
... like depression, obsessive-compulsive behavior.
- AHAndrew Huberman
Incredible.
- 28:13 – 33:23
Transient Ischemic Attacks (TIA); Spinal Cord Strokes
- AHAndrew Huberman
I should've asked this earlier, but, um, TIAs, transient ischemic attacks. Um, I think most people a- assume or know that the symptoms of stroke include, you know, sudden weakness, maybe hemiparalysis of the face, confusion, slurring of the words. Of course, these symptoms can be the consequence of other things as well. Um, what are some of the symptoms of transient ischemic attacks and is there anything that people can take for transient ischemic attacks? A- and I, of course, would love for you to inform us, uh, what a transient ischemic attack is.
- GSGary Steinberg
Right, so a transient ischemic attack or TIA is a reversible stroke. Uh, it results in a temporary loss of function such as, uh, inability to move, partial paralysis or complete paralysis, but then it resolves, uh, inability to speak, visual problems, double vision, blurred vision, loss of vision. Uh, it can cause, uh, slurred speech, uh, or difficulty understanding language, imbalance problems walking, even cognitive problems. So it can vary depending on what part of the brain it affects. In the past, it was defined as a neurologic deficit due to lack of blood flow that lasted less than 24 hours. But now that we have such sophisticated imaging like MR scan, some of these patients who have a TI- what would've been considered a TIA before lasting minutes or up to 24 hours, on MR scan have been shown to have a little stroke. So now, the definition is a little different if there's an E- if you do an MR scan and it shows a new abnormality, a new stroke, then it's called a stroke rather than a TIA. Um, so there's a little overlap there, but it's a temporary, um, loss of- of neurologic function due to lack of- lack of blood flow or in- in some cases, a hemorrhage.
- AHAndrew Huberman
My understanding is that people can also have strokes in their spinal cord, um, because spinal cord tissue is after all central nervous system tissue. I think most people don't realize this but the- the tail end of the brain, the- the brain stem as we're talking about before essentially extends down the, uh, the spinal column, uh, sort of like a- a long tail, right? Um, uh, uh, down to, uh, the base of the pelvis really. Um, so-... we call it the spinal cord, but it's all brain. It's contiguous with the brain. So, uh, how often do y- you observe, um, spinal strokes and what are some of the symptoms of spinal stroke?
- GSGary Steinberg
Yeah. It's much less common, um, than, uh, a stroke involving the brain, uh, probably because there's less tissue involved.
- AHAndrew Huberman
Mm-hmm.
- GSGary Steinberg
Uh, the spinal cord is supplied by, um, an anterior spinal artery, that's an artery on, on, on this side, and by two-
- AHAndrew Huberman
So for those listening, sorry, it'd be the, um-
- GSGary Steinberg
Sorry. Th-
- AHAndrew Huberman
... on the stomach side of the-
- GSGary Steinberg
Exactly.
- AHAndrew Huberman
... of the body. Yeah.
- GSGary Steinberg
And it's supplied by two arteries, posterior spinal, on the backside. So if there's an interruption to blood flow in any of those arteries, it can cause death of tissue in the spinal cord and that would result in a neurologic deficit depending on where it is. So if it occurred on the stomach side, that whole artery which supplies the, the two-thirds of the spinal cord, um, on the stomach side, uh, and it involved both sides of the spinal cord, it would cause, uh, paralysis of both legs and a partial sensory, uh, deficit what we call loss of pain and temperature 'cause that's where those pathways are. If the problem was on the backside of the cord, it would cause a, a problem potentially with, uh, a light touch sensation in the legs, um, if it was below the, um, it was in the, uh, below the cervical region, uh, and, uh, problems with what's called proprioception, that's the ability to recognize where, uh, your position of your joints is. So it depends on where it is. Um, some of the, uh, uh, vascular problems I deal with actually do involve the spinal cord and you can develop other problems there. Um, for instance, you can have a direct connection between a abnormal artery and a vein in the spinal cord which doesn't cause a typical stroke by blocking blood flow, but it causes more of that venous problem we discussed where there's so much blood going directly from the artery to the vein, bypassing the capillaries, that the veins become engorged, the blood can't get out of the spinal cord, and the spinal cord becomes congested and patients can present with problems, uh, walking or, uh, sensory problems. If the, uh, spinal cord is involved in the cervical region up high, then the arms can be involved as well.
- AHAndrew Huberman
I see.
- 33:23 – 38:24
Stroke Risk: Alcohol, Cocaine & Other Drugs
- AHAndrew Huberman
I should've asked this earlier, but is there any relationship between alcohol intake and the propensity for stroke or hemorrhage or any of these other things?
- GSGary Steinberg
Yeah. That's a good question. Yes. There is, uh, a, there, there, the, uh, uh, uh, people who, who indulge or overindulge, uh, uh, are at risk for developing, um, uh, stroke problems. So it's another contributer, contributory factor which can promote, um, problems with the, with the blood vessels. Um, clots, but also hemorrhage.
- AHAndrew Huberman
Ah.
- GSGary Steinberg
So i- it can make the blood vessels more fragile. Another factor I see commonly, um, in patients who develop aneurysms, those are blisters on the blood vessels in the brain, and they're like little balloons and as they enlarge they rupture just like a balloon can burst. Um, some of the patients I see, uh, are not just smokers, but indulge in, uh, other drugs. So cocaine, methamphetamines, uh, markedly increase the risk of developing these aneurysms or developing hemorrhage, bursting of a blood vessel.
- AHAndrew Huberman
And is that because those drugs tend to increase blood pressure during their use? Um...
- GSGary Steinberg
It's because they damage the vessels and they also cause hypertension. Yes. It's both factors. So when I operate on, uh, on these patients and looking at the vessels, um, they are rag- they're, they're ragged. They're very thin. They're not normal vessels. They lack structural integrity so it contributes to the development of, of poor vessel integrity. And drugs like cocaine and methamphetamine can jack the blood pressure up, uh, and that could cause a hemorrhage in these, these, um, problematic vessels. Yes.
- AHAndrew Huberman
So it sounds like the message is clear, uh, avoid cocaine use, avoid methamphetamine use, and avoid excessive alcohol intake.
- GSGary Steinberg
That's r-
- AHAndrew Huberman
If you want to avoid stroke.
- GSGary Steinberg
Right.
- AHAndrew Huberman
Yeah.
- GSGary Steinberg
And throw smoking in there, too.
- AHAndrew Huberman
Mm-hmm. It's interesting because for a lot of years there was so much discussion about red wine being good for heart health. Now it's debated. The moment I say that, people will send a bunch of studies that say, "Yes." I, my stance on the more recent data is that if you had to pick, you'd drink less or not drink as opposed to drink. Um, but I'm curious what your take is on this.
- GSGary Steinberg
Well, you know, this is interesting and, um, I'm always quite amazed at, at, um, the way people change their behavior based on one study that comes out even if it's a good study. So yes, it used to be, um, uh, considered beneficial if you drank red wine. And then for a while i- uh, studies showed any wine was beneficial in moderation. And, um, and that used to be two drinks a day for men, one drink a day for women, and in the latest studies which have been surfacing this year suggest no alcohol is good.
- AHAndrew Huberman
Yeah.
- GSGary Steinberg
But, you know, next year maybe that, uh, we're back to, oh, you know, wine is the best thing you can do for your, in moderation, for your, your brain and heart health. So it...
- AHAndrew Huberman
Yeah. It's tricky. My read of the data, uh, and here I mean the data across multiple n- certainly not every study, but multiple studies, is that, um, zero to two drinks per week is seems to be the range that everyone agrees is safe, at least for non-alcoholic adults. Um, and then once you get out past two drinks per week is when it gets into the gray zone where some people say it's good, some people say it's neutral, some people say it's bad, but that once you get up past, you know, four or five servings of alcohol per week-It's pretty clear to me it's not a good situation.
- GSGary Steinberg
Well, that was the prevailing theory until this year, and, uh, I don't know if you've kept up but in the past, you know, few months, there have been several articles published saying, um, no wine, no alcohol is good. But then you have to balance that against the fact that alcohol, um, for many people tends to relieve stress.
- AHAndrew Huberman
Mm-hmm.
- GSGary Steinberg
So, um, you know, if you're relieving stress-
- AHAndrew Huberman
Mm-hmm.
- GSGary Steinberg
... maybe it counteracts any adverse effects, so complicated issue, but-
- AHAndrew Huberman
Yeah.
- GSGary Steinberg
... my theory is, um, moderation is the key to life, uh, and, um, uh, you know, and, uh, happiness also we know promotes longevity.
- AHAndrew Huberman
Yeah, absolutely. I- I agree with you. I'm not heavy-handed about the alcohol thing. I always just say, you know, do as- do as you wish but know what you're doing. Um, and I think many people who heard our podcast episode about alcohol, who stopped drinking alcohol, who- or who elected to drink less did so, I'm told, um, because they really didn't enjoy it that much to begin with, so it more or less gave them permission to drink less, uh, not that they needed it but they took it. Uh, anyway, I think it's a really interesting area, as you mentioned, probably lowers, um, stress, um, probably also disrupts patterns of sleep in the gut microbiome so there's, you know, you- you can't escape in biology, there's always some, uh, mod- modulatory influence on something else.
- GSGary Steinberg
Exactly.
- 38:24 – 39:55
Sponsor: AG1
- GSGary Steinberg
- AHAndrew Huberman
I'd like to take a brief break and acknowledge our sponsor, AG1. By now most of you have heard me tell my story about how I've been taking AG1 once or twice a day every day since 2012 and indeed that's true. I started taking AG1 and I still take AG1 once or twice a day because it gives me vitamins and minerals that I might not be getting enough of from whole foods that I eat, as well as adaptogens and micronutrients, and those adaptogens and micronutrients are really critical because even though I strive to eat most of my foods from unprocessed or minimally-processed whole foods, it's often hard to do so, especially when I'm traveling and especially when I'm busy. So by drinking a packet of AG1 in the morning and oftentimes also again in the afternoon or evening, I'm ensuring that I'm getting everything I need, I'm covering all of my foundational nutritional needs, and I like so many other people that take AG1 regularly just report feeling better, and that shouldn't be surprising because it supports gut health and, of course, gut health supports immune system health and brain health and it's supporting a ton of different cellular and organ processes that all interact with one another. So while certain supplements are really directed towards one specific outcome like sleeping better or being more alert, AG1 really is foundational nutritional support. It's really designed to support all of the systems of your brain and body that relate to mental health and physical health. If you'd like to try AG1 you can go to drinkag1.com/huberman to claim a special offer. They'll give you five free travel packs with your order plus a year supply of vitamin D3 K2. Again, that's drinkag1.com/huberman.
- 39:55 – 46:45
Traumatic Brain Injury (TBI), Concussion: Sports, Testing & Recovery
- AHAndrew Huberman
Speaking of lifestyle factors, um, anytime we hear about traumatic brain injury or concussion, people immediately seem to think about football, um, but I've been told by colleagues of ours in neurosurgery at Stanford and in neuroengineering that most head injuries are not from football, they're not even from sport, they're from construction work accidents, they're from car accidents. What is your, um, take on, you know, somebody, let's say, um, God forbid, gets rear-ended in a- in a car accident, maybe gets whiplash, maybe they're feeling a little off like maybe they have a minor concussion, maybe there was some, um, movement of the brain that wasn't good, what's the going consensus on how to deal with that? Um, sleep more, but then they tell you not to sleep excessively. Um, should people take blood thinning agents? I mean, obviously avoid alcohol or certainly don't get another head injury anytime soon, but, you know, what do we know about TBI and concussion that- that can help people move through that period in the- in the weeks and months afterwards where it's really scary, you know, if you've ever had a hard head hit, you know, and they go, they might scan you, they might not see a bleed but it's- it's kind of scary when you feel a little bit off because you've been hit in the head.
- GSGary Steinberg
Yeah, it's a great question and there's, uh, a lot of interest in concussion now. Um, I got very involved in this back in the '90s 'cause I was the 49ers neurosurgeon-
- AHAndrew Huberman
Hmm. I didn't know that.
- GSGary Steinberg
... um, for a decade from 1990 to- to 2000. (laughs)
- AHAndrew Huberman
How were they doing at that point? I remember the dynasty-
- GSGary Steinberg
Oh-
- AHAndrew Huberman
... of the '80s-
- GSGary Steinberg
Well-
- AHAndrew Huberman
... or the '90s are good
- NANarrator
Yeah.
- GSGary Steinberg
Oh, they- they were in Super Bowl contention. In fact, uh, I took care of Steve Young-
- AHAndrew Huberman
Yeah, he's a local guy.
- GSGary Steinberg
... who, yeah, Steve's a great guy and Steve, a really smart guy, um, uh, in fact he has a- a- a law- law degree from, uh, Brigham, uh, Young. Uh, Steve was quarterback then and they were in Super Bowl contention and, uh, Steve had had some, uh, concussions, and, um, I actually sent him back to play when he recovered, uh, so you can examine someone, um, uh, and get a decent idea of how they're recovering from- from a concussion. Uh, Steve unfortunately had a- a- a- a bad concussion at one point and, um, he ended up retiring which was the smartest thing, I think, uh, for him in the end, and he's become very involved with, um, studying concussions and- and, uh, trying to figure out better ways to, um, to diagnose them, uh, prevent the sequela for football players including, uh, changes in equipment and- and- and in- in, uh, tackling and that kind of thing. Um, but concussion is, we've learned a lot since the 1990s. At that time, uh, concussion, um, was not known, even repeated concussion, to cause CTE, chronic traumatic encephalopathy, in football players. CTE, which became a hot topic, was known only in boxers, so I became very well-informed at the time about, uh, concussions and it was surprisingly (laughs) little-known, um, soccer players had a high incidence of concussion, uh, at- at that time. It wasn't known if there were long-term sequela-... and usually, there are not u- long-term sequela, um, as long as you don't get repeated concussions. Um, so, um, now what we generally recommend, uh, if someone has a concussion, um, we usually get an MR scan if it's severe. MR scans usually don't show anything. They would show a contusion if there's any bruising of the brain, but, um, they don't show the, the, the molecular, um, abnormalities that occur with a concussion. So, the best way to, um, figure out how severe it is and when a, when a person has recovered is to do more sophisticated neurologic testing. Uh, eye tracking is a very sensitive way, um, to, to, to, to detect problems with, um, with the brain after a concussion because you won't track as well, and in fact, many sports, uh, football, hockey, uh, are incorporating, um, preseason eye tracking testing.
- AHAndrew Huberman
I see.
- GSGary Steinberg
Um-
- AHAndrew Huberman
To get a baseline.
- GSGary Steinberg
To get a baseline.
- AHAndrew Huberman
Interesting.
- GSGary Steinberg
Of course, some of the players will, um, game the system s- because they still don't want to be taken out, so they may try to perform not as well as they, they could.
- AHAndrew Huberman
On their eye tracking?
- GSGary Steinberg
On, on... Yeah, on their, uh-
- AHAndrew Huberman
I see. They throw the test, so that-
- GSGary Steinberg
They throw the test, so their baseline is... I mean, you know, I don't think that's very common, but that's a way you can game the system. But, uh, as long as it's performed well, that's a very good way, uh, of, of detecting, um, subtle problems with the brain. Well, you're a vision scientist, so you, you understand how important, um, uh, all the circuits are, um, i- in terms of... And the visual system is unique because it tests, uh, the brain from the retina all the way back to the occipital lobe. So it's the whole longitudinal axis of the brain that's being tested.
- AHAndrew Huberman
Mm-hmm. Yeah, I'm always struck by, uh, when I see these news, newsreel highlights of a, you know, a player goes down, they stay down, um, and then, you know, they're helped up and everyone cheers, and then they might hobble off, take a few moments, and then, you know, how are they gauging the decision to put the person back in? And the reason it's perplexing to me how they would determine that is that, uh, you and I both know that the neurons, the nerve cells in the brain very likely, um, could be injured, maybe even on their way to death after a head injury. But that the actual dying off of the tissue could take several minutes, hours, maybe even days. So putting someone back in to get hit more, um, seems really risky, but at the same time, that's their profession, that's their choice. And so you don't necessarily want to make the decision to take someone out of a game or a job, um, or have them stop driving if they don't actually need to stop. So it's, it's a tricky thing.
- GSGary Steinberg
It is tricky, and I think we have better, uh, methods of, uh, even at the, uh, uh, if you're talking about sports on the sideline of doing testing. Um, there are neurosurgeons there now, uh, who are part of the process. Um, uh, as far as recovering, uh, in general, it's good to not stress the brain, but, uh total absence of sensory, you know, uh, information, sensory deprivation for long periods is not a good idea.
- AHAndrew Huberman
Right. Just staying home in the dark with sunglasses on, also not a good idea.
- GSGary Steinberg
Mm-mm. Exactly.
- AHAndrew Huberman
Right?
- GSGary Steinberg
So you want to make sure the brain still has input, but you don't want to, um, overstress it when you're recovering from a concussion.
- AHAndrew Huberman
Mm-hmm.
- 46:45 – 48:31
Statins; TBI & Aspirin; Caffeine & Stroke Risk
- AHAndrew Huberman
Sounds like doing all the things to keep blood pressure relatively low, um, LDL cholesterol relatively low. So interesting what you said earlier that statins might be vascular protective even in the absence of high cholesterol.
- GSGary Steinberg
Yeah, there's a lot of good evidence for that. In fact, some studies have suggested that taking statins reduces the risk of cognitive decline in- including conditions like Alzheimer's.
- AHAndrew Huberman
Interesting. I know that statins are a bit of a controversial topic, um, among listeners because some people, um, report, I think I have this right, that statins can give them a kind of a brain fog if they take the wrong one or excessive amounts? Yeah.
- GSGary Steinberg
Uh, yeah. It, it-
- AHAndrew Huberman
I'm not challenging what you're saying. I just hear the-
- GSGary Steinberg
No, no, no. It's, it's-
- AHAndrew Huberman
I just hear the shouts in the-
- GSGary Steinberg
... still controversial.
- AHAndrew Huberman
... in the, in the comment section and I'm just... I don't take a statin, but my cholesterol is in check. Um, but I'm hearing more and more about some of these benefits of statins. That's interesting.
- GSGary Steinberg
Yeah, yeah.
- AHAndrew Huberman
Yeah.
- GSGary Steinberg
And the, the, the information is still emerging. For a traumatic brain injury, in general, you, uh, not a good idea to take, uh, uh, an aspirin as opposed to a stroke or a TIA, uh-
- AHAndrew Huberman
Where you would want to take an aspirin.
- GSGary Steinberg
Right, right.
- AHAndrew Huberman
Right.
- GSGary Steinberg
Because if you have injuries, say you have, uh, a contusion to the brain and there's some, uh, some traumatic damage, taking a blood thinner might cause that to worsen or cause of hemorrhage.
- AHAndrew Huberman
What about caffeine? Is there any evidence that caffeine can increase stroke or ischemia? I like coffee and I like, uh, yerba mate tea, so I'd be reluctant to give it up, but I consume it in moderation. Is there any direct relationship there?
- GSGary Steinberg
I don't know any relationship-
- AHAndrew Huberman
Oh, good.
- GSGary Steinberg
Uh, unless it-
- AHAndrew Huberman
Thank goodness.
- GSGary Steinberg
Unless you're taking so much that your blood pressure is sky-high.
- AHAndrew Huberman
My blood pressure tends to be pretty low.
- GSGary Steinberg
But lots of benefits, uh, uh, um, evidently to, to caffeine in terms of, of health.
- AHAndrew Huberman
Yeah, I agree with you there. Um, I have a question about
- 48:31 – 51:53
Exploratory MRI: Benefits & Risks
- AHAndrew Huberman
something that many people are starting to do now, which is to get, um, exploratory MRI. I actually did one of these. Um, I wasn't gifted one. I just decided to bite the bullet and pay for it. It's a whole body scan. They put me in the tube, did a MRI, get everything from tip to toe, um, and I learned a few things. I learned that I have like a slight... I think it's L3 or L4 disc bulge that explained a little bit of like pseudo sciatica, and I've been able to work around that, um, and keep that strong. I learned that fortunately for me, I only have one white spot on the brain. I was told that you could have one per decade. I'm nearing 50, so I feel very lucky there, especially given that I've...... hit my head a few times skateboarding and doing martial arts and things like that, but, um... So I feel lucky, but I also know people that go in for these scans and get the report that, you know, they have a, um, a growth of some sort or they have multiple white spots, as they're called, on the brain, which is kind of damage to, to tissue, the neural tissue. You know, what is your thought on these, um, exploratory/preventative scans? Do you think they're useful? Um, do you feel like they cause undue concern? I mean, this is a new thing, people going out and getting their brain scanned.
- GSGary Steinberg
Yeah, and people are getting total body scans. So, I think there are, uh, benefits and risks involved. So the benefit is that you might pick up, uh, something that should be treated, like an early cancer, uh, or a large aneurysm in the brain, which would have a higher tendency to bleed. But many times, and I see patients all the time who are referred for a tiny aneurysm, um, blister on a blood vessel in the brain, that was found incidentally on a total body scan. And these aneurysms, which can be one or two millimeters, sometimes we don't even consider those as, as real aneurysms. Um, they don't need to be treated in most cases, um, and so it's, uh, it- it's a little controversial, because people can be worried about them even if they're reassured. Other examples are you find something in the brain or elsewhere in the body, you're not sure what it is, and then in order to determine what it is, patients start having more invasive biopsies and tests which can lead to what we call iatrogenic injuries. That's, iatrogenic is caused by the physicians. (laughs) So, uh, I think you have to be very thoughtful when you interpret the results of, of these, um, total body or, or, or even brain scans, and, um, I- I would recommend talking with a specialist about it, um, if, if, if you're concerned. But, um, you know, people wonder. I have this, uh, we were discussing it earlier today actually, um, with one of your colleagues, and what if you're found to have a 1.75 millimeter aneurysm, if it's really even an aneurysm? Should you change your lifestyle? And for something like that, I would recommend no, you should forget about it, get a follow-up scan, but you may very well live and die with, with this little blister that is of no consequence. So, uh, as I say, I, I think you have to be careful about how you interpret and, and how you, uh, act on, on these, uh, findings.
- 51:53 – 59:52
Blood Pressure, Lifestyle Factors; Tool: Feeling Faint, Hydration; Sleep
- GSGary Steinberg
- AHAndrew Huberman
Maybe we can talk about lifestyle factors, because I think anyone listening to this is gonna think, "I don't want a stroke, I don't want transient ischemic attack, I don't want hemorrhage, I don't want any of this stuff." And we already discussed a little bit about how what's good for your heart generally is good for the brain, but, you know, I think most people strive to eat well, meaning not excessively, also not undereat, um, to hopefully eat a lot of unprocessed or minimally processed foods, and to avoid smoking, perhaps, um, avoid alcohol in excess, avoid hard drugs, um, get exercise. Um, and so, you know, I think people generally try and do all these things, get good sleep, et cetera. Um, but at some level, I think everyone also wants to know, like, w- when are they in their safest, um, kind of shape for avoiding a stroke? Is, is there a sort of a blood pressure cut off where we could say, "Okay, you know, if you keep your blood pressure, resting blood pressure below blank, you're doing pretty well," um, "and if your cholesterol is below blank, you're doing pretty well," and then you just, you know, while keeping moderation, uh, in mind, try and live a life that, um, you know, reduces the probability of getting a stroke or a, or some other, you know, blood-related neural attack?
- GSGary Steinberg
Well, I think it has to be individualized to some extent, and, um, over time, the standards and the guidelines have changed. It used to be if your systolic blood pressure, that's the upper number, was under 130, 130 or under, that was considered normal and, and it would not lead to problems. Now, the guidelines suggest that 120 or lower is better-
- AHAndrew Huberman
Mm-hmm.
- GSGary Steinberg
... in large r- you know, studies. But, um, as an example, uh, when my blood pressure gets under 120, I feel lightheaded. In fact, I had an event, uh, about 15 years ago when I was overdoing it, like I shouldn't have been.
- AHAndrew Huberman
Overdoing exercise or overdoing-
- GSGary Steinberg
Overdoing everything. I was in my f- I was fif-
- AHAndrew Huberman
A Stanford faculty member that overdoes something?
- GSGary Steinberg
It's hard, it's hard to believe.
- AHAndrew Huberman
That was a joke that, among Stanford faculty.
- GSGary Steinberg
I was 56, and I operated all day in two operating rooms. Um, I got done early. Um, it was in the spring, and I took a run up to The Dish, and then I took a red eye to Houston for a meeting, and I emailed on the flight, got an hour or two of sleep, went to the meeting. It was fine. Uh, it was a stroke meeting with a bunch of scientists, uh, neurologists and scientists. There were about 120 people. There were two neurosurgeons there, plus me. And, um, drank some coffee. At noon, I went for a run 'cause I like running, and in Hou- at that day in Houston, it was, um, 90 degrees and 85% humidity, and got back, had a glass of, um, tea, went back to the meeting, had some more coffee, and then as the afternoon session opened up, I started to feel lightheaded, and, um, next thing I know, I'm looking up at the chandelier, and they're, they're, they're shouting, um, "Stroke, cardiac arrest, seizure," and they're gonna, starting to pump on my chest. So they rush me to the hospital where I had, uh, a simultaneous workup for cardiac arrest and stroke, and after, um, um, make the story short, after, uh...... a hundred thousand dollar workup, it was determined I had a faint because I was overdoing it. So, since then, I, now I try to get seven to eight hours sleep a night.
- AHAndrew Huberman
Right.
- GSGary Steinberg
But, but I, so-
- AHAndrew Huberman
That's clearly the bedrock of health, yeah.
- GSGary Steinberg
So I increased, I used to get three to five hours sleep a night.
- AHAndrew Huberman
Yeah.
- GSGary Steinberg
Now I get seven to nine if I can do it.
- AHAndrew Huberman
Mm-hmm. Mm-hmm.
- GSGary Steinberg
Uh, cut back on, on, on c- on coffee, on caffeine. And, um, uh, I don't push myself to exercise like I used to if I'm feeling a little fatigued. I'm on an antihypertensive agent but I, I actually don't take it every day because, um, for me, it's better to have a pressure 125 to 135, uh, and it's true for some of my patients. If you've got some disease in your arteries, you may not wanna have such a low blood pressure so I would individualize it. But in general, um, you wanna take care of your body, like I've learned and probably maybe you've learned over time. But... (laughs)
- AHAndrew Huberman
I'm learning. I mean, this is very interesting. I've, I tend to have low blood pressure. It sort of runs in my family to have low blood pressure. Um, I can definitely relate to the, um, hard driving, um, ambition phenotype. I think it's c- it's worth people hearing this because it's characteristic of a lot of people in high intensity professions, and I made the joke about Stanford faculty, but, um, it's true. I think that if you're ambitious you tend to overdo a bit more. That's something I'm certainly working on and I've, um, run a very busy life and learning to slow down, prioritize sleep, prioritize meditation, non-sleep deep rest is something I've benefitted from a lot, journaling, things of that sort that really just kind of slow the pace. I think that, um, you know, in the landscape of health optimization, we can often put ourselves into modes of excess in the other direction. Um, meaning doing t- so much to try and avoid, uh, issues with health that we end up creating issues with health. But yeah, certainly reducing caffeine intake and prioritizing sleep are, are key. So th- I appreciate that you shared that story. So if somebody has naturally low blood pressure and starts to feel a bit, um, let's just say kind of sleepy or woozy in the afternoon, would you recommend, um, that they obviously not take a, a, um, pressure lowering drug but that they w- uh, add a bit of salt to their diet, that they, um, feel free to, um, you know, to, to exercise less? I'm a little bit confused. I l- I also love to run and, and do resistance training.
- GSGary Steinberg
Right. Well, I would recommend they take their blood pressure. So, um, you want to try to correlate any symptoms you're having with vital signs that you modify, right? So, take your blood pressure if you're feeling faint. If it's low, uh, one thing you can do, uh, easily is to hydrate. That was something else. I used to not drink much because y- I don't want to have to pee in the operating room.
- AHAndrew Huberman
Mm-hmm. Yeah, I can imagine that'd be pretty uncomfortable.
- GSGary Steinberg
And, yeah, so...
- AHAndrew Huberman
I don't wanna be the patient that you're operating on when you have to go use the bathroom.
- GSGary Steinberg
Yeah, so now...
- AHAndrew Huberman
Yeah.
- GSGary Steinberg
And then, uh, I'll reveal that I, um, had a kidney stone, which is common among surgeons. Uh, this was a decade ago, and since then, uh, I hydrate all the time. So I hydrate to the point that my urine is crystal clear all the time.
- AHAndrew Huberman
And that helps with some of the brain clarity?
- GSGary Steinberg
Mm-hmm.
- AHAndrew Huberman
So interesting. I've done a little bit of work with people in the Special Operations community and, you know, I think people hear about them and they think, "Oh, you know, what's, what's the magic potion that they're taking? What are they doing?" And they do a number of very interesting things, um, but one of them is they really emphasize hydration. They're just like, "Hydration, water, sometimes water with electrolytes if they're w- working in, in, in hot conditions." But just hydration, hydration, hydration.
- 59:52 – 1:01:27
Sponsor: LMNT
- GSGary Steinberg
- AHAndrew Huberman
I'd like to take a brief break and acknowledge one of our sponsors, LMNT. LMNT is an electrolyte drink that has everything you need. That means the electrolytes sodium, magnesium, and potassium in the correct amounts and ratios and nothing you don't, which means no sugar. Now, I and others on this podcast have talked about the critical importance of hydration for proper brain and body functioning. Even a slight degree of dehydration can diminish cognitive and physical performance. It's also important that you get adequate electrolytes. The electrolytes sodium, magnesium, and potassium are critical for the functioning of all the cells in your body, especially your neurons, your nerve cells. Drinking LMNT dissolved in water makes it very easy to ensure that you're getting adequate hydration and adequate electrolytes. To make sure I'm getting proper amounts of hydration and electrolytes, I dissolve one packet of LMNT in about 16 to 32 ounces of water when I wake up in the morning and I drink that basically first thing in the morning. I'll also drink LMNT dissolved in water during any kind of physical exercise I'm doing, especially on hot days when I'm sweating a lot, losing water and electrolytes. They have a bunch of different great tasting flavors of LMNT. My favorite is the watermelon, although I confess I also like the raspberry and the citrus. Basically I like all the flavors. And LMNT has also just released a new line of canned sparkling LMNT, so these aren't the packets you dissolve in water. These are cans of LMNT that you crack open like any other canned drink, like a soda, but you're getting your hydration and your electrolytes with no sugar. If you'd like to try LMNT, you can go to DrinkLMNT, spelled L-M-N-T, .com/huberman to claim a free LMNT sample pack with the purchase of any LMNT drink mix. Again, that's DrinkLMNT.com/huberman to claim a free sample pack.I'm
- 1:01:27 – 1:05:16
Chiropractic Neck Adjustment & Arterial Obstruction; Inversion Tables
- AHAndrew Huberman
gonna tell a horror story, but not, I wanna repeat, not to demonize chiropractors. Here's, here's the positive story. I had a back thing that, my back hurt, and I wasn't sure what I needed to do and a chiropractor, um, gave me some exercises to do that essentially were like the up dog movement in yoga that my understanding is it helped the, the disc bulge just kind of work its way back into the spinal column and it worked terrifically well. I took no medication, I required no surgery, and I eventually learned to correct some imbalances that have led me to not have that issue again. It was really remarkable and this chiropractor essentially, um, saved m- me from surgery and, and I'm, uh, forever grateful. So there, I think there are excellent chiropractors out there. Um, but when I was a postdoc, uh, living in San Francisco, I had a roommate, I believe she was a neurology resident, and she came back from the clinic at UCSF and she told me this story that a patient had come in who was experiencing some hemiparalysis of the face. That patient, I believe it was a young woman, um, had gone for a, a neck adjustment or head adjustment at a chiropractor-
- GSGary Steinberg
She ended up with a dissection of her artery.
- AHAndrew Huberman
Right, and-
- GSGary Steinberg
Yeah.
- AHAndrew Huberman
... something had happened-
- GSGary Steinberg
Yes.
- AHAndrew Huberman
... and she had essentially a stroke.
- GSGary Steinberg
Yes.
- AHAndrew Huberman
And so I, I share both these stories to make very clear that I have nothing, um, against chiropractors, but I think like any health practitioners, they come in a range of talents. Um, uh, and this was really, like for me, um, an alarm and I decided at that point I would never allow a chiropractor to adjust my neck. F- I said, "Okay, you can, you can make adjustments to my back, you can give me suggestions about exercises to do." But how common are these, um, this, uh, you said it's a hemidissection, um?
- GSGary Steinberg
It, it's a dissection of an artery, e- either the, uh, vertebral artery in the back or the carotid artery up, uh, closer, um, in the front.
- AHAndrew Huberman
Mm-hmm. So no cutting when you say dissection. They're making, basically making an adjustment.
- GSGary Steinberg
Well, well, what-
- AHAndrew Huberman
Yeah.
- GSGary Steinberg
Well, what happens is, um, and I, I agree with you. I'm, we're on the same page. Uh, I recommend patients if they're gonna have chiropractory, not to have manipulation of their neck 'cause that's what occurs. It's not common, but, uh, I see it. We see it. What happens is the artery is damaged. Um, the manipulation of moving the bone and the soft tissues causes a tear in the wall of the artery. And w- a- and what occurs interestingly, is that the blood that's usually in the, the space, the lumen, the, the middle of the artery gets into the wall and causes a false lumen, a false passage. And that, that blood in the wall pushes part of the wall into the, the main artery obstructing flow and sometimes causing a clot to form that can be dislodged and go up to the brain.
- AHAndrew Huberman
Yikes. So...
- GSGary Steinberg
(laughs)
- AHAndrew Huberman
And there's no way to know whether or not this is gonna happen.
- GSGary Steinberg
No. That's why I recommend not having, uh, neck manipulation by a chiropractor. Even if it's rare, um, it's, it, it's so devastating when it occurs that, uh, personally, I, I, I would avoid that.
- AHAndrew Huberman
Mm-hmm. Um, yes, I tell the chiropractor, uh, stay away from anything, um, above the shoulders, please. (laughs) Um, and then the back work has been beneficial. Again, these exercises perhaps the most beneficial thing about it. Um, as long as we're there, I realize it's a bit of a niche condition, but what about hanging upside down? I had one of these inversion tables. I really enjoyed that thing, but then once I looked at my camera phone while I was hanging upside down and it looked like I was gonna blow a gasket from all the vasculature in my forehead. Is it bad to hang upside down?
- GSGary Steinberg
No evidence that it's bad.
- AHAndrew Huberman
Oh, good. Oh, good, maybe I'll get an inversion table again. Um, as long as you don't stay there, of course. You got, at some... Okay,
- 1:05:16 – 1:10:49
Kids, Tackle Football, Soccer, Boxing; Mild Concussion
- AHAndrew Huberman
great. Um, would you let your kids play football or rugby?
- GSGary Steinberg
That's a great question. I would not. Uh, that's my personal decision. I think there are a lot of benefits to, um, uh, children playing, uh, football, rug- like any sport. Uh, it's a team sport. A lot of good skills are learned. Um, besides the, you know, just the, the, the physicality of it, the coordination, uh, but being a team player and the socialization. But, uh, I think talking about tackle football, um, uh, I think, um, the risk, there is still risk. We're just learning about it and even, um, high school players who, who, um, uh, many years ago were found to have multiple concussions are showing up when they, when they're doing autopsies, uh, uh, with some of this tr- uh, chronic traumatic encephalopathy. Um, I wanted to play football as a kid, and I'm not that big. I mean, I'm a big guy, but, um... And my parents didn't let me which is fortunate because, I mean, I- I'm sure I would've been, would've been, you know, uh, put at risk for injuries, not just head injuries, other injuries. Uh, my son, who's a very good athlete, he played four years of high school, uh, baseball and soccer, was asked to try out, uh, for the quarterback position his senior year. And we went out to try out, but, and he decided, um, you know, with my encouragement not, not, not to play.
- AHAndrew Huberman
Did he go to Gunn High School?
- GSGary Steinberg
Yeah. Uh, he went to Menlo.
- AHAndrew Huberman
Okay. I went to Gunn.
- GSGary Steinberg
(laughs)
- AHAndrew Huberman
Our football team was, at that time, was bad enough that there was no incentive to play.
- GSGary Steinberg
(laughs)
- AHAndrew Huberman
What about soccer and heading the ball? I've actually heard that can be problematic which to me, at first when I heard that, I, I was like, "No. There's no way." I mean, the ball is so light, but is there any evidence that repeated, you know, heading the ball-
- GSGary Steinberg
There is. It's again, it's, i- i- it's, it's not, uh, uh, incontrovertible, but, um, uh, there is some evidence that multiple headings can, can cause some, some concussions and some long term injury. Um, again, when I studied this in detail, um, o- a- as a 49ers, uh, neurosurgeon back in the '90s, there was very little data. Although there was some evidence even then that soccer players had a, uh, high incidence, uh, particularly female soccer players had a high incidence of, of, uh, of concussion surprisingly. Uh, but now there's much more evidence that head injuries and even heading the ball may lead to some, you know, some, some, some injury.
- AHAndrew Huberman
I feel like if a sport is not your profession...... the risk-benefit analysis is pretty clear. Like, like, if, like, why box? I understand it's a great sport, there's a lot to learn there, um, done a little bit of it in the past, but, but unless you're gonna get paid substantial amounts of money, and maybe even then, it's probably not worth it. Uh-
- GSGary Steinberg
Well, I feel the same way. Um, uh, it is different for professional athletes. I mean, this is their job. Um, y- you know, I remember talking with, with Steve Young at one point about y- you know, continuing to play or, you know, finally deciding to retire, and, uh, I was thinking, what if, you know, I was asked to retire as a neurosurgeon at the prime of my career? Um, y- you know, uh, it's your profession, it's your income, it's your, you know, it's how you i- identify yourself. Um, e- uh, you know, uh, your self-esteem is dependent on it. Your family maybe put pressure on you as a professional athlete. Um, if you're not a professional athlete, I, I think for me, and this is my, my own opinion individually, I think, um, there's less of a controversy. And what... There's so many other sports which, uh, uh, benefit in the same way, um, as, as football or, or boxing. Um, why not, why not, you know, participate in those? That's my feeling, but I know it's a controversial subject.
- AHAndrew Huberman
Yeah. Um, uh, maybe we can circle back a little bit on a, uh, fairly common scenario. Um, you're in the attic and you're looking for something, you stand up, boom, you hit your head on a beam and, you know, kind of dizzy for a bit. Or, uh, recently our, uh, podcast team was on tour in Australia and the way that the, the, uh, shelf over the kitchen sink in our, um, Airbnb was arranged, it was certain that everyone pretty much would hit their head hard on that thing at some point. Does one need to worry about one kind of dizzy-inducing head hit, um, from everyday life? You know, I think a lot of people are kind of scared, like, d- do, do they do brain damage, or is the, the evolutionary adaptation, which is the thick skull, um, sufficient to, you know, keep us safe in most cases?
- GSGary Steinberg
I don't think you need to worry in general, especially if your symptoms resolve within a relatively short period of time. So-
- AHAndrew Huberman
Such as how long? A day or two?
- GSGary Steinberg
Y- yeah. I mean, you know, even if you have a mild concussion and you recover within a day or two, I don't think there's, uh, any need to worry or get a scan or... Uh, and, and it's a commonplace occurrence.
- AHAndrew Huberman
Mm-hmm. Yeah. I think, um, your answer will set a lot of minds at ease, because, um, people do worry. I mean, it, th- there's something so mysterious about the stuff that occurs inside the cranial vault. We can't look to something, we can't, you know, take our pulse. Um, it's just, you know, it's so hard to know what's going on in there. Um-
- GSGary Steinberg
Well, as you say, that's why we developed very thick skulls, to protect the, the most important
- 1:10:49 – 1:17:36
Nerve Regeneration, Stem Cells, Stroke Recovery
- GSGary Steinberg
organ.
- AHAndrew Huberman
Because after all, the tissue doesn't regenerate. Um, at least not much of it.
- GSGary Steinberg
Well-
- AHAndrew Huberman
There are a few areas where there, where there are neurons that can replenish.
- GSGary Steinberg
You know, I'm gonna take, um, issue with you at that-
- AHAndrew Huberman
Oh, good.
- GSGary Steinberg
... because the, the prior notion, of course, was that once nerve cells in the brain die, they don't regenerate. And, uh, for a long time, it was thought you don't produce any, any new sh- nerve cells, any new stem cells in the brain. Um, and we used to think after an injury, uh, or, uh, a disease like a stroke, when that tissue is damaged and you were paralyzed or you couldn't talk, that there was no way to recover, that those circuits were, were dead. Uh, it turns out that is not true, and we are learning that, I think, in recent years. Um, when I trained, there was no hope to restore function in patients who had a stroke, traumatic brain injury, spinal cord injury, uh, uh, and, um, other diseases, uh, ALS, Lou Gehrig's disease, um, Parkinson's disease. Now, we are learning that, uh, there is hope. We know that stem cells do form in the adult brain. That's not controversial anymore. We know that other circuits can take over for circuits that were dead, um, and we know now, and this is some of the work that we're doing with chronic stroke patients who we thought could not recover after six months at all, we know that there are ways of, um, promoting, uh, regeneration or recovery of function. We're still working out the details of that.
- AHAndrew Huberman
Inhales.
- GSGary Steinberg
But, um, for instance, we've done studies, and this is still in, um, clinical trial phase, with patients who are years out from a stroke, they've been through rehab, uh, they've been through physical therapy, and 90% or more of recovery after a stroke occurs in the first six months. After that time, you know patients are not gonna recover. And now, we are finding in some of our, uh, early trials with patients that if you, for instance, put in stem cells into the brain, uh, or, um, if you... Another treatment which was, uh, approved by the FDA, the very first for chronic stroke, if you put a stimulator on the vagus nerve in the neck and stimulate, coupled with physical therapy, intensive physical therapy, you can improve arm function in those patients. In our patients that we've treated in multiple trials, we're seeing early indications that patients years out from a stroke can start to recover function in their arms, in their legs, in their speech. And we don't know all the mechanisms, but the old notion that these circuits are dead is simply not true. They can be resurrected. And so, um, you know, this is part of the, the, the excitement about, um, discovery and, um, doing research, and trying to translate into the clinical arena.
- AHAndrew Huberman
Yeah, oftentimes this boils down to really critical of-the-moment decisions. I'll tell a story. Um, I won't reveal the- the hospital or the- the exact players involved, but, um, some years ago, an ex-girlfriend of mine, um, who then was just somebody I was, uh, friends with, um, slash dating, contacted me and said that her dad had had a stroke. And I was, um, near that hospital so I went, um, and spoke to the resident and the resident, who was overseeing the case, essentially said, "Look, it- it's hopeless. There's a huge necrotic piece of tissue in there. Um, the probability of any kind of quality of life is essentially zero. My suggestion..." and I was there as- as, um, the resident made this suggestion, would be to remove him from life support, essentially. And, um, the other members of the family were like, "Oh my goodness," right? This is not a situation anyone wants to be in. Um, I made a couple of calls including to, um, someone who's previously been a guest on this, uh, podcast, who's highly qualified to know about this sort of thing. They asked a couple of questions about the location of the stroke, which side of the brain it was on, and said, um, "Keep him alive. There's a good chance that he'll have, um, some degree of recovery of function." So, that's what they did. And indeed, um, while he lost some motor s- um, abilities, um, lost some speech abilities and has some disruption of affect where he'll s- sort of spontaneously laugh or cry from time to time, he has, at least by my observation, been able to enjoy substantial amounts of life interacting with grandkids, um, enjoying holidays, and actually took, I was told, some, um, some physical steps at some point with assistance, with a walker. He's gone- d- done a lot of physical rehab. Um, obviously a really hard situation, but it told me that oftentimes when we think that all is lost, not all is lost, even in people in their 70s.
- GSGary Steinberg
Right, i- it has to do with plasticity.
- AHAndrew Huberman
Mm-hmm.
- GSGary Steinberg
And, um, we all wish were neonates or infants because, um, the body, including the brain, is so plastic. That's the ability to regenerate tissue and circuits and recover. So, if an infant has a stroke and is paralyzed on one side, usually they can make an excellent, if not complete, recovery. Um-
- AHAndrew Huberman
This is the, as I recall from my undergraduate years, the Kennard principle. If you're gonna have a brain injury, have it early in life.
- GSGary Steinberg
Exactly.
- AHAndrew Huberman
Right.
- GSGary Steinberg
So, um, I mean, you notice this too, when I cut myself now, it can take a week for that cut to heal. When my granddaughter, who's six years old, cuts herself, the next day it's totally healed. So-
- AHAndrew Huberman
Yeah, k- little kids are like salamanders, right? They almost f-
- GSGary Steinberg
And-
- AHAndrew Huberman
It's al- by the way, that was a biology joke.
- GSGary Steinberg
(laughs)
- AHAndrew Huberman
They're not like salamanders. They... But, um, salamanders can reab- uh, regenerate entire limbs by the maintenance of a small stem cell population at the- at the tip of the- the limb bud, um, or what would be the limb bud, um, and it is remarkable how kids can regenerate without a scar. They can oftentimes... They can't grow an entire hand back, but it's kind of striking how much plasticity there is.
- GSGary Steinberg
And that's what we're trying to develop are new ways of promoting plasticity in the adult brain, as an example. So, we think stem cells injected through various mechanisms, stimulation of the brain or the vagal nerve as an example, can promote plasticity in. In a sense, we think what's happening is, um, that these methods can turn the adult brain into an infant brain in some
- 1:17:36 – 1:21:27
Stem Cells, Immune System, Activity
- GSGary Steinberg
ways.
- AHAndrew Huberman
Where are the stem cells coming from in these experiments?
- GSGary Steinberg
It depends. Um, there are different sources. So, um, some of the studies I've done previously with other companies, uh, they made the stem cells either from, uh, bone marrow donors, uh, so they were mesenchymal, or, uh, another group made the cells from, uh, e- from fetal, uh, neural tissue.
- AHAndrew Huberman
Okay, so just to orient people, inside the bone you have the marrow. Most people know that, um, because they've ordered it at a restaurant. Um, cow marrow, that is, um, uh, typically. Um, the cells within the marrow, um, contain, as I recall, a h- hemopoietic population, so a population of- of sort of potential blood cells, you know, cells that can become blood cells or other things, and if taken out, put into a Petri dish, and given the appropriate factors, you can drive the fate of those stem cells to be, say, neurons or cardiac cells, and then you're taking those cells and you're injecting them into the brains of patients in the hopes that they will re- uh, become neural cells, neurons that will incorporate into the circuitry.
- GSGary Steinberg
Actually, that was the initial notion 20 years ago when we started doing this, was that these cells you put in, uh, become... These exogenous cells you inject become neurons and astrocytes and oligodendrocytes, all the cells in the brain, and that the neurons reconstitute circuits. That is not f- how they work. The way they work, and this is why it may not, uh, matter what particular type of stem cell you put in, the way they work primarily is by secreting very powerful proteins, molecules, growth factors that promote native recovery. So, they promote angiogenesis, they promote native neurogenesis, endogenous gliogenesis, synaptogenesis, but the main benefit may be that they modulate the immune system. That's what we're finding. So, by modulating somehow the immune system in the brain, they are able to induce plasticity and recover function.
- AHAndrew Huberman
Interesting. I- I'm tempted here to weave in the- the stories that date back to the '90s but that we see more and more of, mostly studies in rodents but a few in humans, showing that there are dormant stem cell populations in certain compartments of the brain, the dentate gyrus of the hippocampus, the olfactory bulb, et cetera, that upon...... hyperoxygenation or increasing blood flow to the brain, largely by virtue of exercise, but also sometimes by way of engaging in learning tasks and exercise, that you can basically cause the release of stem cells that normally would lie dormant. Is that, um, literature reason enough to suggest that people who've had a stroke, um, continue to move their body, to walk, get exercise, maybe do resistance training, maybe even some skill-related training?
- GSGary Steinberg
Eh, yes. There's a lot of evidence that, um, activity, physical therapy, even forced activity, um, is very beneficial, and it's not just, um, stimulating endogenous stem cells in the brain, but it's multiple mechanisms. Uh, it's recruiting, uh, circuits that were not involved before. For instance, studies have been done on stroke patients who make a recovery show that, um, not only is the site of the stroke improving in some cases, but the other side of the brain is showing increased activity. So circuits on the other side of the brain may be contributing to the recovery on the, th- the side of the stroke brain. So, it's much more complex than we thought it was.
- 1:21:27 – 1:23:46
Injury & Recovery, Restraint Therapy
- GSGary Steinberg
- AHAndrew Huberman
Years ago, I, um, developed an affection for a literature, it wasn't a very prominent literature, um, but I found it really interesting. Um, it's the work of a guy named Timothy Schallert and, um, Teresa Jones.
- GSGary Steinberg
I, yeah, I know both of them.
- AHAndrew Huberman
Ah, yeah, are you familiar with this? Yeah.
- GSGary Steinberg
Yeah, we almost recruited Tim to, to our department.
- AHAndrew Huberman
Yeah, the sort of overarching theme of this literature was, it was animal work, um, but I think some of it might have been translated to humans, which was that, for instance, if somebody has damage on one side of the brain, uh, because of the way the circuits are organized, and of course, you know this better than anyone, uh, Gary, but that one might experience deficits in limb movement on the opposite side, and that the tendency for somebody like that is to then over-rely on the intact limbs, um, essentially lean on the, the intact limbs. And the approach that they took to try and, uh, recover function was really interesting. They had these animals, and I think eventually there was some human work done, I could be mistaken, t- um, sort of, uh, tie up the, the more active uninjured arm or leg or hand such that they then had, had to rely on the non-dominant, or let's just call it injured, sometimes even flaccid paralysis limb, and in that way, they could generate a lot of plasticity that normally would escape the patient, especially in the days and weeks following the injury. Uh, just forcing movement, uh, or forcing the attempt to move of the injured pathway. I, I find this literature to be so striking and maybe one that, uh, should deserve more attention.
- GSGary Steinberg
Yeah, it's called constraint therapy, and, um, not only has it been shown in, uh, animal studies pre-clinically, but it's been shown in some, uh, clinical studies of patients with stroke. In fact, one of the trials we did with transplanting stem cells into the brain included restraining the good limb to force use of the other limb. So there's, um, some very intriguing data suggesting that that's important. However, some of the animal studies also suggest that you may have to wait a time. If you force use of the, uh, involved limb too soon, it can be detrimental to the recovery.
- AHAndrew Huberman
I see.
- GSGary Steinberg
So, there may be a, a, a, a, an important temporal factor there in terms of the timing of when you do that.
- 1:23:46 – 1:34:59
Neuroprotection After Injury; Mild Hypothermia
- GSGary Steinberg
- AHAndrew Huberman
Is there anything that people can do or take for neuroprotection after an injury to essentially try and rescue neurons that would otherwise die?
- GSGary Steinberg
Right, so this is a, a very interesting subject. Um, back in the late 1980s, 1990s, a lot of emphasis was placed on trying to protect the brain against acute stroke. Different pharmacologic agents were tried. Um, probably, um, 1,000 different drugs were tried which blocked, uh, the pathway leading to cell death. So interestingly, when you deprive the, the brain and the neurons of oxygen and glucose, they don't die immediately, and it takes some time, and it's actually an active process. So the release of these excitatory amino acids occurs. So normally, as you know, glutamate, aspartate are important neurotransmitters in the brain, and you need them to function. But after a stroke when there's a deprivation of oxygen and glucose and a mismatch between the metabolism and the supply of oxygen and glucose, for some reason, there's a release of these excitatory amino acids like glutamate, and that causes an influx of calcium into the neurons, which is the final common pathway to dying. And then there are other pathways that can then lead to release of free radicals and, uh, uh, which are more damaging, and those can cause another type of cell death called apoptotic cell death. That's a, uh, uh, a cell death that occurs and requires protein synthesis. And then, uh, with reperfusion, um, say the artery opens up, then you've got a lot of inflammation. So, these pharmacological treatments, as I say, 1,000 of 'em were tried, um, and they were found to be very effective in pre-clinical stroke models. So we could cure stroke in the lab. My lab studied this for probably 15 years, and, um, y- you know, there was no doubt we could cure stroke if we got the drugs on board even after the stroke, um, within a few hours, but it never was able to be translated to the clinical arena except for one case. So besides drugs that were tried...Um, another method of protecting the brain was tried called mild hypothermia, and that, uh, was a process of reducing the brain temperature and body temperature just a few degrees, from 37 degrees centigrade to 33, and we were one of the first to- to show, um, that that was protective even after the stroke in animals.
- AHAndrew Huberman
Um, my understanding is that when you cool neural tissue, you quiet its electrical activity. In fact, this is a common, um, tool for experimentation in neuroscience laboratories. You know, you want to shut down a- a brain area transiently, you- you cool it down.
- GSGary Steinberg
Right. And i- in fact, deep hypothermia has a profound effect on shutting down the metabolism, so that's why when a- someone, par- particularly kids fall into a frozen pond with- with ice-cold water, they can survive there for half an hour, uh, and make a complete recovery because their body temperature is dropped down to very low, like 20 degrees centigrade, but this is less. This is just a few degrees. So the amount... there is a slight decrease in the metabolic activity, but that does not account for all the protection. It's due to the fact that hypothermia, mild hypothermia, blocks many of those detrimental pathways. It blocks partly the release of those excitatory amino acids, glutamate, it blocks the calcium influx, it blocks the inflammation, uh, and so, um, that's probably why it works so well. It even blocks that other pathway of programmed cell death. Um, because it hits all these pathways, it's multifactorial, it's very effective, and in fact, it was finally shown in the early 2000s in prospective randomized studies that one type of stroke, actually two types I should say, two types of stroke are benefited by cooling the brain quickly. One is cardiac arrest from ventricular fibrillation, and prospective studies which were published in 2002 showed that if you, uh, cool patients who have cardiac arrest and then are resuscitated out in the field down to between 32 and 34 degrees centigrade from 37, much better outcomes neurologically.
Episode duration: 1:55:03
Install uListen for AI-powered chat & search across the full episode — Get Full Transcript
Transcript of episode nqNEtdHVUjM
Get more out of YouTube videos.
High quality summaries for YouTube videos. Accurate transcripts to search & find moments. Powered by ChatGPT & Claude AI.
Add to Chrome