Episode 193: Tommy Wood and his new book bust the belief that the adult brain is fixed
Digest
This podcast features Dr. Tommy Wood, author of "The Stimulated Mind," who challenges the misconception that the adult brain is fixed and inevitably declines with age. He emphasizes the brain's remarkable neuroplasticity and adaptability throughout life, supported by evidence from animal studies (barn owls) and human experiments (vision inversion, juggling, London taxi drivers). The discussion delves into the historical context of neuroscience, the limitations of reductionist approaches, and the crucial roles of glial cells and cardiovascular health in maintaining cognitive function. Dr. Wood also touches upon the Chimane people's low dementia rates, the influence of genetics like ApoE4, and a re-evaluation of Alzheimer's disease research, concluding with a preview of practical brain health strategies.
Outlines

Introduction to Dr. Tommy Wood and "The Stimulated Mind"
Introduction to STEM Talk, its host Don Conegas, and guest Dr. Ken Ford. They introduce Dr. Tommy Wood, a neuroscientist and author of "The Stimulated Mind," focusing on brain health and preventing cognitive decline. Dr. Wood discusses his book's genesis, motivation, and the core theme challenging the notion of a fixed adult brain.

Challenging Brain Aging Myths and Historical Context
The misconception that the adult brain is fixed and inevitably declines with age is challenged. Historical ideas of retirement and limitations of traditional epidemiological studies are discussed, alongside evolutionary aspects of brain development and aging.

The Brain's Adaptability: Evidence and Experiments
Theories of aging are touched upon, emphasizing the adult brain's capacity for adaptation and improvement. The barn owl experiment and human studies with inverted vision goggles demonstrate neuroplasticity driven by environmental challenges and learning.

Higher Cognitive Functions and Brain Structure Adaptation
Experiments show adaptation in higher cognitive functions through learning new skills like music and languages. Juggling and the spatial memory demands on London taxi drivers illustrate structural and functional brain changes in response to specific cognitive challenges.

The Enigma of Brain Understanding and Neuroscience History
The overarching theme of the brain's capacity for change is reiterated. The complexity of the human brain is discussed, acknowledging that a complete understanding remains elusive. The contributions of Santiago Ramón y Cajal to neuroscience are highlighted.

Methodologies and Limitations in Brain Research
Methodologies used by neuroscientists, including reductionism and microscopy, are explored. The limitations of reductionism and the concept of emergence are discussed, along with the brain as a self-referential system and the "broken radio" analogy for biological complexity.

Clarifying Neurogenesis, Neuroplasticity, and Glial Cells
The distinction between neurogenesis and neuroplasticity is clarified, emphasizing plasticity's role in adult brain adaptability. The crucial, often overlooked, importance of glial cells in brain function and health is discussed.

Blood Supply, Lifestyle, and Dementia Risk Factors
The critical role of blood flow and cardiovascular health in maintaining brain function is emphasized. The Chimane people's low dementia rates are presented as a case study, linking brain health to lifestyle. The influence of ApoE4 and environmental interactions is also discussed.

Alzheimer's Research, Historical Misconceptions, and Trends
The history of Alzheimer's disease research is traced, including a re-evaluation of the index patient's diagnosis. Encouraging trends of decreasing age-specific dementia incidence are discussed, attributed to improved health and lifestyle factors.

Preview of Part Two: Brain Health Strategies
A preview of the next segment is provided, focusing on practical strategies for stimulating neuroplasticity and improving brain health through lifestyle and environmental factors.
Keywords
Neuroplasticity
The brain's ability to reorganize itself by forming new neural connections throughout life, allowing adaptation to new experiences and learning.
Cognitive Decline
A reduction in cognitive abilities like memory and attention, which can be a normal part of aging or a symptom of neurological disorders.
Dementia
A syndrome characterized by a decline in cognitive abilities severe enough to interfere with daily life, with Alzheimer's disease being the most common cause.
Alzheimer's Disease
A progressive neurodegenerative disorder causing brain shrinkage and cell death, characterized by amyloid plaques and tau tangles.
Glial Cells
Non-neuronal cells in the nervous system that provide support and protection to neurons, crucial for overall brain health.
Neurogenesis
The process by which new neurons are formed in the brain, playing a role in development and a focus of therapeutic research.
Cardiovascular Health
The health of the heart and blood vessels, closely linked to brain health as it ensures adequate blood flow to the brain.
ApoE4
A genetic variant associated with an increased risk of Alzheimer's disease, though its impact can be modified by environmental factors.
Brain Health
Maintaining optimal cognitive function and preventing neurological disorders through lifestyle, environment, and understanding brain adaptability.
Neuroscience
The scientific study of the nervous system, including its structure, function, development, and disorders.
Q&A
What is the main misconception about the adult brain that Dr. Tommy Wood challenges in his book?
Dr. Wood challenges the long-held belief that the adult brain is fixed after development and inevitably declines with age. He presents evidence that the brain remains adaptable and capable of improvement throughout life.
How did the barn owl experiment initially influence our understanding of the adult brain, and what did later modifications reveal?
Initially, the barn owl experiment with prism glasses suggested adult brains couldn't adapt. However, later studies showed that when housed socially or required to hunt, adult owls demonstrated significant adaptation, revealing the importance of environmental interaction.
What is the difference between neuroplasticity and neurogenesis, and why is this distinction important for understanding brain adaptability?
Neurogenesis is the creation of new neurons, which is limited in adult brains. Neuroplasticity, however, is the brain's ability to reorganize and form new connections between existing neurons. This plasticity is the primary driver of adult brain adaptability.
Why are glial cells considered as important as neurons in brain function?
Glial cells, including astrocytes, oligodendrocytes, and microglia, play vital roles in supporting neurons, regulating electrical activity, maintaining brain structure, clearing waste, and modulating immune responses. Their diverse functions are crucial for overall brain health.
How does cardiovascular health impact brain health and dementia risk?
Good cardiovascular health ensures adequate blood flow to the brain, providing essential oxygen and nutrients. Poor cardiovascular health, such as high blood pressure or atherosclerosis, can impair brain function and significantly increase the risk of dementia.
What factors contribute to the low rates of dementia observed in the Chimane indigenous population?
The Chimane people's low dementia rates are attributed to their physically demanding lifestyle, a diet rich in vegetables and lean protein, and consequently, very low levels of cardiovascular and metabolic diseases.
Is the ApoE4 gene variant a definitive predictor of Alzheimer's disease?
No, the ApoE4 gene variant is a risk factor, but not a definitive predictor. Its impact is largely influenced by environmental interactions and lifestyle. In some populations, its association with dementia risk is diminished or even protective.
What historical misconceptions about Alzheimer's disease have influenced research, and what is the current understanding?
Historically, Alzheimer's disease research heavily focused on amyloid and tau pathology. While these are involved, recent failures of anti-amyloid therapies have led to a broader understanding, acknowledging the roles of inflammation, vascular health, and other factors.
What encouraging trends have been observed regarding dementia incidence?
Studies show a decrease in age-specific dementia incidence, meaning individuals are less likely to be diagnosed with dementia at any given age compared to previous decades. This is linked to improved cardiovascular health, increased brain reserve, and lifestyle changes.
What is the primary takeaway message regarding the adult brain's potential?
The primary takeaway is that the adult brain is not fixed and declining but possesses significant capacity for plasticity and improvement throughout life, heavily influenced by environmental factors and stimulation.
Show Notes
Today we have Dr. Tommy Wood, a neuroscientist and frequent STEM-Talk guest who joins today on the eve of the publication of his first book, “The Stimulated Mind: Future-Proof Your Brain from Dementia and Stay Sharp at Any Age.”
Tommy is an Associate Professor of Pediatrics and Neuroscience at the University of Washington, where his laboratory focuses on brain health across human lifespan. Tommy is a colleague and good friend who also is a Visiting Research Scientist here at IHMC.
Today we talk to Tommy about his mission to dispel the myth that the brain is doomed to decline with age. His book, which publishes on March 24 but is available for pre-order on Amazon, offers science-backed strategies to enhance mental sharpness and prevent cognitive decline, including Alzheimer’s disease.
There was so much to unpack with Tommy about his book, that we decided to split his interview into two parts. Today we talk to Tommy about the history of neuroscience and how researchers go about studying the brain. We also have a conversation with Tommy about what is holding us back in terms of addressing an ever-increasing burden of cognitive and mental health disorders we are experiencing not only here in the U.S., but also around the world. In part two of Tommy’ interview, which will air in a few weeks following today’s episode, Tommy shares science-backed strategies to help people future-proof their brains.
Tommy’s lab at the University of Washington focuses on brain health across the lifespan. He conducts research that focuses on ways to treat a range of brain injuries, including babies born preterm and adults who experience brain trauma. He also investigates lifestyle factors that affect long-term cognitive function and increase the risk of dementia.
Tommy has a bachelor’s degree in biochemistry from the University of Cambridge, a medical degree from the University of Oxford, and a Ph.D. in Physiology and Neuroscience from the University of Oslo.
Show notes:
[00:04:04 ] Dawn opens our interview congratulating Tommy on his new book, “The Stimulated Mind.” Dawn asks Tommy what inspired him to write his first book.
[00:07:29 ] Since writing the book consumed more than 18 months of Tommy’s life, Dawn asks Tommy if he thinks he’ll write another one.
[00:09:36 ] Dawn asks if it’s fair to say that the overarching theme of “The Stimulated Mind” is that the conventional belief the adult brain is fixed and incapable of change is wrong.
[00:17:35 ] Ken explains that Tommy opens his book with a story about a study on barn owls, where researchers outfitted a group of owls with prism goggles that altered the perceived position of objects in the owls’ vision. While young owls were able to quickly adapt to the change in their vision and return to normal behavior and activities, adult owls, even after months of wearing the goggles, were unable to adapt and would miss mice that were directly under their beaks. However, the research group amended their study design and found something interesting. Ken asks Tommy to explain what they found when they amended their design.
[00:22:40 ] Ken asks Tommy to share how a human study, which outfitted participants with goggles that flipped their vision upside down, demonstrated the adaptability of the adult brain.
[00:25:32 ] Ken asks if these sorts of adaptations have been seen as beyond basic sensory modalities in higher cognitive functions.
[00:31:25 ] Dawn zooms out in our discussion and asks Tommy, given the falsehood of our previous understanding of the adult brain as being fixed, what exactly do we know about the brain.
[00:35:36 ] Dawn asks Tommy to talk about Santiago Ramón y Cajal, who is considered the first neuroscientist.
[00:38:41 ] Dawn mentions chapter two of Tommy’s book, “How do Neuroscientists Study the Brain,” in which Tommy explains the complexity of the brain, which is comprised of almost 100 billion neurons which compose nearly a quadrillion synapses. Given the complexity of the brain, Tommy notes in his book that even an organ as complex as the human brain is incapable of fully comprehending its own complexity. Dawn asks Tommy to talk about how he and his colleagues approach studying the brain.
[00:43:30 ] Ken notes the parallels between attempting to understand the function of the brain based on an understanding of its individual components to the process of trying to understand how a piece of software works on a computer by systematically studying the computer’s hardware. Ken goes on to start a discussion on the parallels between the brain as a self-referential system that is so complex it cannot even fully understand itself, to various paradoxes as well as Gödel’s theorem, while noting that such comparisons are a false equivalency, and the brain is not a formal system in the sense of mathematical proofs. Still, Ken notes, the parallels are interesting.
[00:47:07 ] Dawn asks Tommy about a humorous but insightful section in his book that illustrates the complexity of neurological research called “Can a Biologist Fix a Broken Radio.” Dawn asks Tommy to explain what this analogy is about.
[00:52:18 ] Dawn notes that the modern belief that the adult brain is fixed stems from work done by Cajal in the late 1800s where he claimed that after development the adult brain was no longer capable of regeneration or plasticity. Dawn asks Tommy to touch more on this.
[00:56:26 ] Ken explains that while people are likely familiar with neurons, as the basic building block of the nervous system, most people are less familiar with glial cells, which, until recently, were considered to play a minor role in the brain. However, Tommy in his book, argues that glial cells should be seen as just as important as neurons. Ken notes that within the neuroscience community there is a renewed interest in these cells.
[01:02:35 ] Dawn shifts the conversation to ask about the importance of cardiovascular health in brain health.
[01:06:35 ] Dawn explains that Tommy ends part one of his book by looking at what the brain is actually for, and to answer that question, he first explains that although the brain is capable of adaptation and change over a lifespan, it requires the right environment. To illustrate this, and the fact that dementia is not predetermined, Dawn asks Tommy about the indigenous Tsimané people of the Bolivian Amazon, who have some of the lowest rates of dementia in the world.
[01:08:27 ] Ken asks Tommy if it’s true that these people also have a lower prevalence of APOE 4/4 and 3/4 genotypes.
[01:11:26 ] Dawn asks, since one of the aims of Tommy’s book is to help people improve their cognitive function and reduce their risk for dementia, if he could give listeners a brief history of Alzheimer’s disease.
[01:17:07 ] Ken explains that general warnings that as we get better at treating various diseases and increasing lifespans, we will see an overwhelming number of people develop age-related dementia. Recent studies out of Europe, however, have shown the opposite trend, and that the likelihood of being diagnosed with dementia at the age of 70 is now lower than it was 20 years ago.
[01:22:43 ] Ken and Dawn close out part one of our interview with Tommy by explaining that in part two we will focus our discussion with Tommy on ways people can stimulate neuroplasticity in their adult brains. Ken asks Tommy to close out by briefly discussing the recipe for changing and improving the adult brain.
Links:
STEM-Talk episode 47 with Tommy Wood
STEM-Talk episode 110 with Tommy Wood
STEM-Talk episode 111 with Tommy Wood
STEM-Talk episode 128 with Tommy Wood



















