How can something so small control every aspect of your existence? The human brain, with its 85 billion neurons forming over 100 trillion synaptic connections, holds the key to optimizing your cognitive abilities, protecting against age-related decline, and unlocking your full mental potential.
In Life Lessons From a Brain Surgeon, neurosurgeon and scientist Rahul Jandial reveals how understanding your brain’s structure and function can transform the way you approach everything from daily habits to long-term health planning. Keep reading for a detailed overview of the book.
Life Lessons From a Brain Surgeon: Book Overview
The human brain is one of the most remarkable structures in existence. It contains about 85 billion cells—roughly the same as the number of stars in our galaxy—linked with each other in a network of over 100 trillion synaptic connections. In Life Lessons From a Brain Surgeon, Rahul Jandial teaches how this incredible organ works and how you can best care for it.
In addition to his work as a surgeon and neuroscientist, Jandial is an associate professor of neurosurgery at City of Hope Cancer Center in Los Angeles. He’s authored or coauthored more than 10 books and over 100 scientific papers on topics ranging from neuroscience to the biology of cancer. Jandial is also the founder and co-director of the International Neurosurgical Children’s Association, which provides charity hospitals around the world with the training and equipment to perform pediatric brain surgery.
We’ll start this guide by discussing the human brain’s structure and how it functions. We’ll then go over Jandial’s lifestyle suggestions for keeping your brain working at its best, including healthy habits for eating, sleeping, and even breathing. We’ll conclude by listing crucial ways your brain will change as you get older and further lifestyle habits that can protect your brain from the worst effects of aging.
Our commentary will provide additional information about the biology and neurology of the brain to deepen your understanding of Jandial’s ideas. We’ll also compare his principles with those of other popular neuroscience books like Robert Sapolsky’s Behave and Barbara Oakley’s A Mind for Numbers. Finally, we’ll offer concrete actionables to help you maximize your brainpower.
Understanding Your Brain
Jandial begins by giving a high-level overview of the human brain’s physical structure. Your brain consists of about three pounds of soft tissue, cushioned by nutrient-rich cerebrospinal fluid and encased in your skull. However, that relatively small structure manages the countless functions that keep you alive and make you who you are.
We’ll start this section with a brief overview of the brain’s anatomy. We’ll then discuss how it gives rise to two of the most remarkable human abilities: language and creativity.
Anatomy of the Brain
Jandial says the most interesting part of your brain is the outer layer, known as the cerebral cortex, which handles higher functions like consciousness and rational thought. The cerebral cortex is less than one-fifth of an inch thick, but intricately folded and wrinkled—if spread out flat, it would form a circle about 16 inches in diameter. These folds maximize your brain’s surface area, allowing it to house more brain cells.
Jandial explains that the brain is physically divided into two hemispheres (literally “half-spheres”). However, the hemispheres remain connected by the corpus callosum: a thick bundle of nerves that carries signals between the two halves.
Within each hemisphere, the cerebral cortex is further divided into four lobes, which handle specific functions. Your frontal lobes, positioned behind your forehead, manage executive functions like planning, making decisions, and carrying out actions. The parietal lobes near the crown of your head process touch sensations, while the occipital lobes at the back of the head interpret visual information. Your temporal lobes, located above your ears, handle hearing and language comprehension.
How Neurons Work Together
Understanding how the brain works requires taking a closer look at brain cells, which are known as neurons. Jandial explains that every neuron has numerous threadlike structures branching out from it toward other neurons. Those threads carry electrical and chemical signals that allow neurons to communicate with each other, giving rise to all of the brain’s functions. This network of connections—axons to transmit signals and dendrites to receive them—makes up about 60% of your brain.
The remaining 40% of your brain consists of the neurons’ central bodies. The core of the neuron contains its DNA, along with the various microscopic structures that allow it to survive (essentially, the cell’s “organs”).
How Your Brain Creates Language
Jandial says people’s linguistic abilities—the ways in which we speak and write—are some of the most impressive and unique functions of the human brain. These abilities emerge from the interplay between the frontal lobe’s executive functions and the temporal lobe’s linguistic functions. The author explains that communication skills require precise coordination between two specialized regions of the brain. Broca’s area, located in your left frontal lobe, enables you to decide what you’ll say and then say it. Meanwhile, Wernicke’s area in your temporal lobe allows you to understand what others have said.
How Your Brain Produces Creativity
Jandial adds that, much like language, creativity emerges from the interactions between different parts of your brain. You experience a creative “spark” when two or more areas start working together, creating new connections between seemingly unrelated ideas. For example, Velcro exists because George de Mestral made the connection between burrs sticking in animal fur and the need for a strong, reusable fastening system.
Your frontal lobes, as always, provide the needed executive functions. In this case, that means keeping your thoughts directed toward a particular goal such as solving a problem or answering a question. This part of the brain is also responsible for keeping you motivated, generally with the thought of a reward or the fear of a punishment. However, the author emphasizes that the creative process involves every part of your brain—the frontal lobes only guide it.
Jandial adds that the best way to engage your creative abilities is to balance periods of focused work with regular breaks to relax and let your mind wander. These periods of downtime are crucial for your brain to form connections between various pieces of information, allowing unexpected insights to emerge. Furthermore, letting your mind wander strengthens the connections between distant areas of the brain. This explains why great ideas often come to you while you’re relaxing, such as when you’re in the shower or doing something you enjoy.
Neuroplasticity: How Your Brain Repairs Itself
To conclude the discussion of how your brain works, Jandial discusses neuroplasticity—the brain’s ability to adapt itself to your needs and heal after injury or illness.
First of all, much like with muscles, the parts of your brain that you use frequently will become larger and more powerful. For example, thanks to neuroplasticity, an artist might have a significantly larger cerebellum than usual, since the cerebellum governs visualization and fine motor skills. This helps to explain why you naturally become more adept at the skills and ways of thinking you practice the most—your brain optimizes the parts of itself that get the most exercise.
Perhaps even more impressively, your brain can heal and reorganize itself after being damaged. Jandial says that in many cases of injury or illness, the surviving brain regions take on the functions of areas that can’t be repaired. This explains how people can recover from conditions like head injuries and strokes, often regaining the same level of cognitive ability they had before.
Optimize Your Brain
Jandial says the best way to enhance your brain is to get the greatest benefits possible from your fundamental biological processes. Consistency is key: Small, manageable adjustments will lead to greater benefits than dramatic but unsustainable lifestyle overhauls. In this section we’ll cover three of the most basic human needs: eating, sleeping, and breathing. For each, we’ll discuss how you can tweak your habits to get greater benefits while meeting that need, and the reasoning behind Jandial’s suggestions.
Optimize Your Nutrition
Jandial urges you to establish eating habits that support your long-term brain health, but still leave room for occasional indulgences. To that end, he suggests focusing on simple, sustainable guidelines for nutrition. For example, straightforward rules like “eat more vegetables than meat” and “stop eating when you’re full” tend to produce better long-term results than elaborate meal plans or strict diets. With that said, the author also offers some specific strategies to help you start developing healthy eating habits to support your neurological health.
One of these strategies is the aptly-named MIND diet—short for “Mediterranean-DASH Intervention for Neurodegenerative Delay”—which Jandial asserts is the most scientifically supported approach to brain nutrition. This diet emphasizes fresh fruits and vegetables, nuts, fish, and chicken, while limiting red meat, saturated fats, and processed foods. Notably, however, the MIND diet doesn’t give strict guidelines for how much of each type of food to eat or when to eat it. Instead, it simply offers general guidelines to eat more of certain types of food and less of others.
Intermittent fasting (IF) provides another evidence-based strategy for brain health. Jandial suggests fasting twice a week for a period of 16 hours (which includes time spent sleeping). These periods without food make your body run out of glucose—simple sugar, its preferred fuel—and start burning your fat reserves instead. In addition to helping you lose weight, the fat-burning process creates helpful byproducts called ketones, which help form new neural connections, as well as slowing age- or disease-related degeneration of the brain.
Why Nutrition Matters
Jandial explains that these specific diet strategies are good for your brain because they work with the blood-brain barrier, which controls which substances cross from your bloodstream into your neural tissue. This protective mechanism ensures that only essential nutrients like oxygen, glucose, and ketones, along with some vitamins and minerals, ever reach your brain.
It stands to reason that maintaining a healthy balance of nutrients that can cross the blood-brain barrier will benefit your neurological health. Conversely, making less healthy choices like ultraprocessed foods and red meat could mean that you’re consuming a lot of calories without providing your brain the nutrients it needs (in addition to the other ways a poor diet can harm your health).
Optimize Your Sleep
Jandial says that most adults need between seven and nine hours of sleep nightly in order to function at their best. He offers a number of strategies to help you get consistent, high-quality sleep, including:
- Keep your bedroom dark and cool: Your mind instinctively associates darkness and cool temperatures with nighttime, so those conditions will help you fall asleep. For the same reason, avoiding bright lights and computer screens for at least an hour before bed will help your natural sleep cycles function properly.
- Use your bedroom only as a bedroom: This will help your mind associate the bedroom with sleep, rather than with work or your hobbies. As a result, you’ll naturally start to feel tired when you enter the room.
- Stick to a schedule: You have an internal clock that will sync to your usual bedtime, helping you to fall asleep and stay asleep through the night. Therefore, maintaining a consistent sleep schedule is one of the simplest and most effective ways to get a good night’s sleep.
- Avoid caffeine after noon: Stimulants like caffeine disrupt your sleep, but many people don’t realize that caffeine can stay in your system for up to 12 hours. Therefore, try to avoid caffeine in the afternoon and evening.
Why Sleep Matters
The fact that people need to sleep is hardly a new insight, but Jandial goes into detail about why you need it and what happens if you don’t get enough. He explains that sleep is when your brain performs critical maintenance and optimization functions, such as forgetting unimportant information and consolidating related memories for easy access.
Conversely, not sleeping enough will make your brain work less effectively. This is somewhat similar to how older computers needed to defragment (reorganize) scattered pieces of stored data and became slow if they weren’t defragmented often enough. Jandial says sleep deprivation affects every aspect of cognitive functionality, from memory formation to emotional regulation. Furthermore, people who consistently sleep less than six hours a night face increased risks of physical ailments like heart disease and diabetes. As a side note, regularly sleeping for more than nine hours leads to many of the same health problems, suggesting that the ideal range is between six and nine hours per night.
Optimize Your Breathing
Finally, Jandial says that even the way you breathe can have major, measurable impacts on your brain. Furthermore, these changes can happen in a relatively short time, and persist even if you go back to breathing how you normally do.
One simple practice the author recommends is to engage in slow, mindful breathing for 15 minutes a day: Breathe in through your nose while you slowly count to four, hold the breath in for another four-count, breathe out while counting to four, then count to four again before taking the next breath. Doing this daily for just two weeks can produce significant improvements in your self-control and emotional regulation.
Why Breathing Matters
The obvious reason why breathing exercises like the one above are helpful is because they encourage you to breathe deeply and efficiently. Doing so enriches your blood and your brain with the oxygen you need to function properly. However, Jandial argues that such exercises are also beneficial because they train you to concentrate and maintain control over your body—this is why they’re often a crucial part of practicing meditation or yoga. Therefore, recalling our earlier discussion of neuroplasticity, these exercises physically strengthen the areas of your brain related to those skills.
How Aging Affects Your Brain
We’ve talked about how to take care of your brain so you can get the most out of it, but one of the biggest concerns people have about their cognitive health is simply getting older, and the changes that come with age. However, Jandial reassures us that the effects of aging are predictable and aren’t always negative—you can focus on maintaining your cognitive strengths while compensating for areas you’re growing weaker in.
We’ll start this final section by discussing the different types of memory and how aging impacts them in different ways. We’ll then conclude with Jandial’s strategies for keeping your brain healthy as you age: lifelong learning, an active social life, and regular physical exercise.
How Aging Affects Memory
One of the most common fears about aging is losing your memory. However, Jandial says the human brain actually has four distinct ways to store memories. Each of those storage systems serves a unique purpose and is affected differently by aging.
The four kinds of memory are:
1) Working memory. This is essentially your brain’s workspace, meaning that it allows you to manipulate information mentally. For example, you use working memory while doing math or trying to follow complex instructions. However, working memory has a very limited storage capacity—you can only work with a few pieces of information at a time—and that capacity decreases as you get older.
2) Episodic memory. This deals with your personal experiences and specific events from your past. Like working memory, this system naturally weakens with age, which is why, for instance, you might vividly remember your favorite childhood TV show, but struggle to remember the plot of a book you read last week.
3) Semantic memory. This is how your brain stores general knowledge about the world: facts, concepts, and basic information like the definitions of words. Barring brain damage from an injury or illness, this type of memory remains strong as you age, allowing you to continue learning new things throughout your life.
4) Procedural memory. This handles your learned skills and habits. This type of memory is highly stable, which explains why you never forget how to ride a bicycle or tie your shoes. As such, age has little impact on your procedural memory.
Protect Your Brain as You Age
While some effects of aging are inevitable, Jandial says that you can keep your brain healthy—and minimize your risk of dementia—with a few key lifestyle choices.
Protection Strategy #1: Lifelong Learning
First, Janidal says that continual, lifelong learning is one of the best protections against age-related cognitive decline. This is because learning drives your brain to keep building and strengthening neural connections, helping to counteract the damage that aging can cause. For example, reading challenging books, learning new skills, and engaging with unfamiliar ideas are all ways to keep your mind sharp and resilient.
The author adds that it’s crucial to find the right level of mental challenge: something that’s possible with your current abilities, but pushes you outside your comfort zone. For instance, learning a new instrument is an enjoyable challenge, but not if you have arthritis that makes it physically difficult for you to play.
Protection Strategy #2: A Healthy Social Life
Second, Jandial says that your social life can protect against cognitive decline. Citing the work of neuroscientist Emily Rogalski, he explains that elderly people with active social lives tend to have better memories and cognitive abilities than peers who aren’t as social. Multiple studies support this pattern, showing that maintaining strong friendships throughout your life can reduce your dementia risk by as much as 50%. Even online social networks can provide such benefits.
With that said, Jandial emphasizes that your personal satisfaction with your social life is what really matters. Therefore, he urges you to socialize just enough to be happy, rather than forcing yourself to be around people as much as possible. The cognitive risks of age come from feeling lonely, not from actually spending time alone.
Protection Strategy #3: Regular Exercise
Finally, Jandial says that regular physical exercise has significant benefits for aging brains. This is because exercise promotes the production of hormones called growth factors that enter your cerebrospinal fluid, nourish your brain, and promote the formation of new neural connections. The author adds that resistance training (exercises like pushups and lifting weights) provides the greatest benefits for elderly people. For reasons that aren’t fully understood, cardiovascular exercises like running are much less effective at protecting and strengthening an elderly brain.
