Summary of Huberman Lab Podcast Episode: The Neuroscience of Your Unique Experience with Dr. David Linden
Podcast: Huberman Lab
9 min. read
— Description —
Discover the fascinating connection between our senses, experiences, and the subjective nature of reality Learn why its crucial to get your kids outside for their long-term eye health Explore the complex interplay between nature and nurture, and how our experiences shape who we are
Uncover the groundbreaking theory of treating depression by targeting inflammation and promoting neuroplasticity Plus, find out why exercise is a powerful antidepressant with no negative side effects Explore the profound impact of our thoughts on our physical well-being.
The Neuroscience of Your Unique Experience with Dr. David Linden
Table of contents
Key Takeaways
Introduction
20:00 – Human Individuality
43:30 – The Role Of Heritability
1:08:05 – Effects Of Mother’s Pregnancy On Child
1:16:00 – Understanding The Cerebellum, AKA “Mini Brain”
1:24:30 – Nature & Nurture
1:30:45 – Inflammation & Depression
1:55:50 – Applications Of The Mind-Body Connection
2:07:00 – About David Linden’s Cancer & How It Shaped His Views
Articles
Books
Other Resources
Key Takeaways
- There is no purely objective world – all senses are based on experience, expectation, and the situation at the moment
- Get your kids outside! Kids who don’t go outside are more likely to be nearsighted later in life
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We get this wrong a lot: “The genome, all your DNA…don’t make a blueprint for making your body and brain…rather, it’s a rather vague recipe.” – Dr. David Linden
- Only a portion of our personality, tendencies, intelligence, etc. is heritable but most come from random nature, different opportunities
- “Nature versus nurture” is too narrow – first, they’re not opposing ideas and often work complementary; nurture should really be replaced with “experience” and encompass everything from in-utero development
- Theory of treatment of depression by reducing inflammation: relief from depression has to do with neuroplasticity; inflammation is a barrier to neuroplasticity – identify the origin of and treat the inflammation to reduce the depression
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“Exercise is about as good an antidepressant as SSRIs and the side effects are only good side effects as opposed to SSRIs.” – Dr. David Linden
- Exercise also keeps blood flow into the brain which dilates and makes vessels more elastic which protects against depression and cognitive decline
- How we think influences our body
Introduction
- Dr. David Linden, Ph.D., (@david_j_linden) professor of neuroscience at Johns Hopkins University School of Medicine and the author of many popular books about the brain. Check out his latest book, Unique: The New Science Of Human Individuality.
- In this episode of Huberman Lab, Andrew Huberman and David Linden discuss what accounts for differences across individual people, the connection between mind and body and the impact on our health, the link between inflammation and depression, and more related to psychology and human development.
- Host: Andrew Huberman (@hubermanlab)
20:00 – Human Individuality
- Scientists only recently identified the nerve endings responsible for sexual sensation in genitals
- The sexual sensation may be experience-dependent
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Much of science seeks to find general principles, ignoring individual variation
- For example, the olfactory system has about 400 receptors; DNA is highly variable from individual to individual – there are odors some love, others hate; some can detect, others can’t
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People are highly individual and contextual when it comes to odor
- There are only a few odors that are innately aversive – other odors are culturally adapted and learned
- There is no purely objective world – all senses are based on experience, expectation, and the situation at the moment
- Uniqueness in visual perception: kids who don’t get outside much are much more likely to be myopic (nearsighted) when they grow up than kids who go outside
- Heat-tolerant people have more of a certain type of saltwater sweat gland innervated
- Evolutionary change is slow but phenomena set by life experience can change within a generation
- Perfect pitch has low heritability – but – ear training at a young age will enhance the likelihood of developing perfect pitch
43:30 – The Role Of Heritability
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Very few traits are entirely predictable based on heritability
- Most traits are a combination of heritable and social
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Genes code for proteins, not traits; genes in the body are rarely solely responsible for one thing
- For example, there’s a gene that determines whether your ear wax will be wet or dry (with 100% heritability) but it also has many other functions in the body
- Speech accent is 0% heritable – it’s entirely dependent on the speech of your peers, not family
- Height is about 85% heritable with the rest attributed to random variation, nutrition, health
- IQ tests administered by trained psychologists aren’t perfect but are predictive of later success
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In developed countries and places not burdened by war or famine, IQ test scores are 60-70% heritable
- In people who are poor, even in developed countries, IQ tests are less heritable
- Good schooling correlates with good medical care, less traumatizing neighborhoods, parents in the home, etc.
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Heritability is estimated by comparing identical twins against fraternal twins but with a major assumption that kids raised in the same family have the same environment
- A more powerful way to estimate heritability is to look at twins reared apart
- Personality traits tend to be about 50% heritable and 50% from random development of the body and nervous system (nothing to do with family)
- “The genome, all your DNA…don’t make a blueprint for making your body and brain…rather, it’s a rather vague recipe.” – Dr. David Linden
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The current evidence of epigenetic inheritance of trauma is skim – there isn’t a biological mechanism and much of the theory comes from research that’s done after the fact
- You’re probably inheriting stress and trauma socially, not necessarily biologically
1:08:05 – Effects Of Mother’s Pregnancy On Child
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Children of women in 1918 who got the flu (in the 1918, pandemic) while pregnant are shorter
- Incidence of schizophrenia, autism (though not called autism at the time) also went up
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First-trimester hypothesis: if a pregnant woman gets the flu in the first trimester of pregnancy, there’s a higher incidence of schizophrenia and autism
- This is possible because interleukin 17 causes disordered development of layers of the cortex, which is anecdotally seen posthumously in autism
- We don’t know the effects of COVID and other illnesses on children in utero
1:16:00 – Understanding The Cerebellum, AKA “Mini Brain”
- The cerebellum (AKA mini-brain) is involved in balance, timing, cognition
- The cerebellum is one of the most complex regions of the brain
- Fun fact: when we read, we’re speaking it in the brain just not in the region that controls speech
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Cerebellum is involved in motor coordination, but its very close proximity to critical regions allows it broadly to function as the region of the brain responsible for trying to predict and react to a future event, or the next thing that’s going to happen
- Damage to the cerebellum causes some clumsiness and poor coordination
- The cerebellum evolved to function in non-motor capacities (though we previously understood it in a coordination capacity)
1:24:30 – Nature & Nurture
- “I have a lot of problems with nature versus nurture as an expression.” – Dr. David Linden
- Nature is meant to mean heritability and nurture is intended to mean your environment and how you were raised but “nurture” is too narrow
- “Nurture” could more practically be replaced with “experience” in the broadest sense – the foods eaten by the mother in utero, bacterial population of the gut, etc. starting from the earliest development
- Nature and nurture are not working in opposition; experience and heredity act in both complementary and opposing ways
1:30:45 – Inflammation & Depression
- The nervous system extends into the body and the body sends neural signals back to the brain
- “The idea that our thoughts can influence our body and our bodily state can influence our thoughts is fortunately just not understood but seems to be accepted and appreciated.” – Dr. Andrew Huberman
- Two ways to get signals to the body: (1) interoceptive neurons – neural signals in the body; (2) hormonal chemicals
- Research in immune signaling molecules (cytokines, signaling hormones of the immune system) in the brain is emerging and will be highly fruitful
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Inflammation and depression theories: (1) inflammation sensing neurons send electrical signals to the brain; (2) immune signaling cytokine molecules produced at the site of inflammation travel to the brain
- Depression is not easily trackable via pharmaceutical intervention because only 1/3 are helped by traditional SSRIs; there is some evidence that people suffering from treatment-resistant depression get relief by reducing inflammation
- Relief from depression has to do with neuroplasticity
- Plasticity in the brain can be intrinsic, synaptic, or morphological
- “Exercise is about as good an antidepressant as SSRIs and the side effects are only good side effects as opposed to SSRIs.” – Dr. David Linden
1:55:50 – Applications Of The Mind-Body Connection
- There are two potential pathways conveying signals from the brain to the body
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Innervated neurons can affect the progression of cancer through their activity – it’s reasonable to hypothesize that certain tumors may respond to meditative practice
- It’s speculative but biologically supported
- Effects of breathwork and deliberate respiration on health are now being widely studied for effects on mental health, physical health, illness
- The problem is there has been a lot of woo science in the past, tarnishing the reputation of the very real brain and body connection
- You can record many places of the brain and find a signature of the breathing rhythm – it’s reasonable that breathwork has real impacts on the brain and its function
2:07:00 – About David Linden’s Cancer & How It Shaped His Views
- A few years ago, David Linden learned he had a very rare cancer: heart cancer
- Lessons: perception of time is malleable – context changes everything, genuinely engaging with own demise is fundamentally difficult because the brain is always trying to predict the future, gratitude for the big things in life (profound love for family)
- His negative emotions and sadness about death are more about the idea of leaving loved ones behind and what they will feel
- Advice based on this experience: appreciate what you have while you have it
Articles
- Ben Barres (Nature)
- A Neuroscientist Prepares for Death (The Atlantic)
- Can a Neuroscientist Fight Cancer With Mere Thought? (The New York Times)
Books
- The Autobiography Of A Transgender Scientist by Ben Barres
Other Resources
- Dr. Leslie Vosshall
- Dr. Catherine Dulac
- Dr. Rachel Herz
- Dr. Karl Deisseroth
- Dr. Gloria Choi
- Dr. Irving Zucker’s Publications
- Dr. Rena Malik: Improving Sexual & Urological Health in Males and Females
- Dr. Oded Rechavi: Genes & the Inheritance of Memories Across Generations
- Dr. Eddie Chang: The Science of Learning & Speaking Languages
- Dr. Robin Carhart-Harris: The Science of Psychedelics for Mental Health
- Dr. Matthew Johnson: Psychedelic Medicine