By Rahul Jandial March 30, 2021 ⋅ 7 min read ⋅ Books
Prologue
This book attempts to separate the BS from the brain science, the hype from the hope.
Chapter 1: An Anatomy Lesson Like No Other
The brain doesn’t actually sit inside the skull; it floats in a natural, shock absorbing fluid called cerebrospinal fluid (CSF).
CSF is produced at a rate of two cups per day from the brain’s ventricles.
CSF serves as the brain’s nourishing liquor and drains away the brain’s waste.
The texture of a living brain is like flan or bread pudding.
The cells on the outer lining of the brain, the cerebral cortex, are the most precious ones.
It’s where most of the magic happens.
Gyrus = Hill, Sulcus = Valley.
60% of the brain is white matter.
Review of dendrites, axons, synapse.
Axons and dendrites never physically touch.
It’s a myth to assign one feeling or cognitive function to each neurotransmitter.
E.g. Excessive dopamine can result in the development of a gambling addiction and becoming hypersexual, and it isn’t just a “feel good” chemical.
Near the outside edge of your eyebrow is Broca’s area.
Penfield’s maps of the somatosensory cortex are so accurate that we still use them today as a general guide to where the motor and sensory functions are located.
One inch above each ear is just above the temporal lobe.
In the living brain, gray matter isn’t gray and white matter isn’t white. Those colors only appear in dead brain tissues filled with preservatives.
Inside a living brain, gray matter is actually beige-pink and white matter is actually pearl-white.
The hippocampus sits in the basement of the temporal lobe.
Usually, either your left or right hippocampus is dominant with the other acting as a spare.
The amygdala is where three imaginary lines intersect, two directly from the eyes and one across the ears.
While it’s true that the amygdalae play an important role in fear, it’s also important for positive emotions.
The amygdala isn’t the fear center, but it’s an intense emotion hub.
The thalamus sits near the bottom of the brain but above the brain stem. It sits at the center of the brain.
The thalamus smooths and refines outgoing muscle commands and modulates incoming sensory information.
The thalamus also directs a stream of incoming and outgoing calls to the right place.
The hypothalamus sits directly below the thalamus and regulates hormones. It’s also a no-fly zone during surgery due to it’s importance.
The brain stem is no thicker than your thumb and controls basic functions.
E.g. Breathing, sleeping, heart rate, consciousness, and pain sensitivity.
Damage to the brain stem doesn’t recover unlike the rest of the brain.
The cerebellum lies behind the brain stem and helps refine physical movements, particularly on coordination and timing.
Glia cells feed neurons with nutrients and oxygen, insulate neurons from each other, destroy invading pathogens, remove dead neurons, and enhance their communication.
Chapter 2: Beyond Memory and IQ
The Flynn effect, that IQ has been steadily increasing over the past 100 years, shows us that intelligence isn’t simply determined by DNA.
Memory works like an area-restricted search, it searches until it finds what it’s looking for, search around that area, and then leave when it’s done.
In other words, it’s similar to a small-world network.
Review of emotional intelligence, grit, and deliberate practice.
The only talent improved is the specific skill practiced.
Chapter 3: The Seat of Language
Review of Broca (speech production) and Wernicke (speech comprehension) areas.
Different areas of the brain handle different languages.
Busy neurons are thriving neurons, and those that aren’t busy tend to wither.
Neurosurgeons are like a cerebral cartographer in search of tiny islands of safe brain tissue.
The brain can’t feel touch; it doesn’t have the ability to know when it’s being touched, cut, or manipulated.
One patient had to go for brain surgery a second time but the first map couldn’t be trusted due to neuroplasticity.
Her language areas had reorganized in response to the surgeon’s previous dissection.
Chapter 4: Unleash Creativity
A slow growing frontal lobe tumor can be confused as major depression or dementia.
Review of the left/right brain myth.
Mind wandering is directly linked to enhanced creativity.
The more your mind wanders, the greater the connections seen between far brain areas.
Fear of failure keeps too many people from daring to express themselves.
To boost creativity, break your routine and spend more time goofing around.
Chapter 5: Smart Drugs, Stupid Drugs
Lost in the conversation about smart drugs is that dose, age, and genetic predisposition matter.
Alcohol isn’t a smart drug, but may helps cognitive functioning in low doses.
E.g. One can of beer every day.
Caffeine might be a smart drug, but the evidence is conflicting.
Cocaine isn’t a smart drug as its highly addictive and a nightmare.
While high on weed, people have reduced attention and reduced performance on psychomotor tasks.
The greatest concern is the growing body of evidence that regular weed use is linked to an increased risk of developing severe psychiatric illnesses.
E.g. Schizophrenia.
Marijuana isn’t a smart drug, but it isn’t a dumb one either.
Modafinil is consider one of the most effective and least dangerous smart drugs.
Tobacco is toxic, but nicotine without tobacco is an interesting drug.
Smokers were found to have a reduced risk of developing Parkinson’s disease.
Nicotine appears to mildly improve cognition, but there’s not enough evidence to say so.
A common side effect of prescription stimulants, such as Adderall and Ritalin, is paranoia.
No study has ever shown these drugs to be true cognitive enhancers.
They don’t make you smarter, they just keep you awake and alert for longer.
Chapter 6: Sleep On It
The brain never rests.
Sleep isn’t a time when the brain rests.
The only time the brain rests is in a medically-induced coma. These patients don’t dream and they’re not asleep.
One purpose of sleep is to transform short-term memories stacked up during the day into long-term memories.
Another function of sleep is to take out the garbage, to erase and forget information built up throughout the day.
Why we dream is still an unsolved mystery.
Sleeping less than 6 hours a night increases the risk of death by 12 percent, while sleeping more than 9 hours increases the risk of death by 30 percent.
Fragmented sleep often feels worse than no sleep at all.
Over-the-counter drugs only work to initiate sleep, but they don’t help you stay asleep through the night.
Recommendations for better sleep
Keep a consistent sleep schedule.
Avoid caffeine in the afternoon and evening.
If you don’t fall asleep after 20 minutes, get out of bed.
Use your bed only for sleep and sex.
Limit exposure to bright light in the evenings.
Turn off electronic devices at least 30 minutes before bedtime.
Chapter 7: Just Breathe
Other organs can go hours without blood flow before their cells die, but neurons survive only a few minutes without blood.
E.g. Getting disoriented if you stand up too quickly because blood hasn’t had time to go to your brain.
Chapter 8: How to Handle Head Injuries
Bullets shot into the sky return and can cause heavy brain and head trauma.
42% of people shot in the head survive and do well enough to be discharged from the hospital within six months.
The vast majority of concussions leave no lasting effect on a person’s mental functioning.
However, getting a second concussion before recovering from the first one is very dangerous.
Chapter 9: Food for Thought
Nearly every millimeter of your body is penetrated by nerves sent out from the brain.
The gut is not a second brain.
Some people insist that breakfast is the most important meal of the day, but there’s no good evidence for that.
Only oxygen, glucose, ketones, some fats, vitamins, and minerals pass the blood brain barrier.
“Eat food. Not too much. Mostly plants.” - Michael Pollan
Chapter 10: How the Brain Heals Itself
Your brain isn’t hardwired.
Most researchers believed that the brain was hardwired up until the 1980s.
Brain tissue isn’t cut like other tissue; its delicately chiseled by the force of suction.
In a hemispherectomy (removing half of the brain), the lobes are removed first before suctioning out the white matter, hippocampus, amygdala, thalamus, and hypothalamus.
Chapter 11: The Bionic Brain
Review of direct brain stimulation (DBS) treatments.
The electrophysiologist can hear when the electrode reaches its target when the sound of spikes changes.
Chapter 12: Shock and Tingle
Review of electroconvulsive therapy (ECT) and transcranial direct-current stimulation (tDCS).
ECT, when properly administered, is the fastest, most effective treatment for depression and bipolar disorder when medications have failed.
Electricity as medicine.
Chapter 13: Stem Cells and Beyond
Review of injecting stem cells and CAR T cells into the brain to treat cancer.
Chapter 14: The Younger Brain
The prefrontal cortex doesn’t fully mature until our late twenties.
Neuronal maturity doesn’t happen at the same pace across the human brain.
Neurons are created at a rate of 250,000 per minute when the baby is in the womb.
Neither the destinations nor the timing is random, as each neuron is expected to arrive at an exact location at a predetermined time.
Brain development involves not just growth, but also death.
Review of synaptic pruning.
Use it or lose it.
Control of the pruning process is incredibly precise, and when it goes wrong, neurodevelopment suffers.
E.g. Autism be due to too many synapses in certain parts of the brain.
The simple fact is that babies and children require stimulation to grow normally.
Most children and adults don’t need to be given vitamin supplements except pregnant women.
Fruit juice is almost as bad as soda in terms of the amount of sugar in them.
Chapter 15: The Older Brain
On average, a person’s brain volume shrinks by about 5 percent per decade after the age of forty.
However, brain atrophy doesn’t equal mind atrophy.
Memory with age
Semantic memory continues to grow with age.
Procedural memory slowly declines with age.
Episodic memory peaks in your mid-twenties and slowly declines throughout life.
Working memory becomes more limited with age.
High blood pressure has been known to increase the risk of cognitive impairment.
The reason education pays off in helping you remain cognitively healthy is because of cognitive reserve: people with extra brain power can afford to lose more before showing signs of decline.
Those who put their brains to better use can withstand greater loss of brain matter.
Physical activity turns out to be one of the absolute best ways to maintain and even improve cognitive health.
Epilogue
Your brain’s health is within your control.
Your willingness to engage in lifelong learning, social engagement, and childlike openness to new experiences will define your brain’s fate.