Friday, August 26, 2011, Stanford University Alumni Center
MacArthur Genius Dr. Robert Sapolsky
is the John A. and Cynthia Fry Gunn Professor at Stanford, with joint
appointments in biological sciences, neurology, neurological sciences, and
neurosurgery. He is also a research associate at the National Museums of Kenya.
Dr. Sapolsky’s research focuses on stress, neuronal degeneration, and aging.
His studies of wild baboons in Kenya have shed light on relationships between
personality, stress-related disease, and the environment. Dr. Sapolsky has
published numerous books, the most recent bearing the title Stress and the Aging Brain.
Dr. Sapolsky began his presentation by saying that he was
happy that no one in the Class of ’59 will ask him for a medical school
recommendation. (This is unusual on this campus, apparently.)
Part of the research for his latest book required his
students to conduct the following studies across the U.S.:
·
Radio station managers reflecting many musical
tastes across the country were interviewed. The study revealed the following
age relationship to music: We set our tastes in our 20s. If they are not set by
our 30s, they will not be set. In fact, the window on developing musical taste
is closed by 35.
·
Sushi restaurant owners in the Midwest were
interviewed regarding food tastes. They were asked: When did sushi come to
town? What is the age of your clientele? The study concluded that the average
age to first try sushi is 23. If haven't tried it by 39, you won't.
·
How was Dr. Sapolsky to study fashion tastes?
Tatoos? No. Earrings on men? No. So he asked his interviewers to contact 49
body piercing parlors across the country and to ask about tongue studs, with
this result: The average age to get a tongue stud is 18. If you don’t have one
by 23, you aren’t going to get one.
Our creativity declines with age--no surprise. But our
creative output decreases at the same time that our criticism of other's work
increases. For example, Albert Einstein is reported to have been less open to
other people’s novelty as he aged. Part of this is due to neuron loss: tremors,
inability to transfer short term memory to long term memory, and disinhibition
are symptoms of the loss.
Development is a lifelong process for brains! You do make
new neurons. This is the hottest study in neuroscience. Back to our research:
Why are the development of musical and sushi tastes limited to young brains?
Dr. Sapolsky has learned that if people change their
disciplines, they reset their clocks. (Note Dr. Carroll Estes’ career change
nine years ago, noted in the Longevity posting on this blog.) It’s healthy to
have a career change every few years. He calls this disciplinary age, as
opposed to chronological age. Note: A UC Davis professor has called being
eminent in your field the kiss of death!
Here’s another interesting branch of psychology: Peer
influence or peer generational influence. You're 15. The last thing you want to
be is like your parents. He sees the exact same thing in other species. When
are lab rats willing to try new foods? In adolescence. Not when they’re
newborns and not in adulthood.
He observed a macaque monkey who had invented two different
feeding techniques. One was to clean a potato with sea water, and then dip it in
salt. She would also separate rice from sand by throwing a handful of rice/sand
into water, where the sand would sink. Monkeys her age or younger—not older--would
copy her techniques.
A study of baboons revealed that when they moved to a new
area, no one older than the one who discovered new foods would try them.
Dr. Sapolsky adds: “If you were a lot older than Darwin,
forget it.” Max Planck stated that new ideas outlive the current generation.
Dr. Sapolsky has learned that he’s been asking the wrong
question. Now he asks: Why is it when we get older we want to stay with what we
know in food, etc.? (Stravinsky's answer: “I want to make sure I'm still here.”)
He assures us that it’s not terrible to lose openness to novelty. An
anthropologist has said: Any time a rare
ecological disaster came along, if there's group memory, you can survive. For
example, the older the elephant matriarch, the better the infant survival rate
in a group of elephants. She remembers where the good watering hole is.
Is it ok if Dr. Sapolsky listens to Bob Marley over and over
again? Do some 80-year-olds need to get tongue piercings? Sure. Sure. He
states: “An open mind is a prerequisite to an open heart.” Though he does warn,
“If you’re listening to James Taylor, you are probably searching out relaxed
jeans.”
Short term memory is up to a minute or two old. Long term
memory is five minutes old or older.
It’s thanks to long term memory that you can remember your native
language or the smell of what your grandmother used to bake. It is related to visceral
memories. Music is in the visceral memory category. That's why an Alzheimer's
patient will remember “God Bless America.”
The Fatal Attraction
Phenomenon
Here’s the weirdest thing Dr. Sapolsky's ever worked on:
toxoplasma. When pregnant, women automatically stay away from cats, and the
only place toxo can reproduce is in the guts of cats. Cats excrete it, and it’s
eaten by rats. Take a lab rat: It has a hard wired aversion to the smell of a
predator (e,g,, cat urine). It will go to the other side of the cage if it’s
exposed to the smell of a cat or cat feces. Toxo turns the aversion into an
attraction! Predator aversion occupies just one circuit in the brain.
Dopamine is all about reward, and cocaine provides dopamine.
A new study reveals that toxo increases dopamine. It can hijack a reward
pathway. Toxoplasma-infected people say things they shouldn't and have accidents
from reckless driving. They impulsively commit suicide. Seventy percent of
people in France test positive for toxoplasma as a result of what they eat.
Worldwide the number is 30%. Positive tests for toxoplasma are likelier closer
to the equator (where one walks around barefoot and can get infected from feces
on the ground). We can develop toxoplasma from uncooked meats. However,
toxoplasma has a subtle effect and is not usually tested for in humans.
Why Zebras Don’t Get Ulcers
Changing the subject: Why don't zebras get ulcers? Because
they're not smart enough to. A zebra has no psychological stress. This is in
contrast to us. We don't fight over getting the next food animal. No. We stress
over being passed over for promotion.
Stress can kill neurons—and can make neurons less able to
withstand stress. Stress increases the risk of Alzheimer's Disease. However,
interventions can always help; it’s never too late to seek help.
The definition of stress for a zebra is any action that
knocks its body out of homeostatic balance. A half-starved lion is a stressed
lion. A human being also experiences stress if you’re knocked out of
homeostatic balance—or if you think you're about to be knocked out of
homeostatic balance.
For most animals, stress results from an immediate awareness
of danger. In humans, stress in a dangerous situation can save your life. If stress
comes some other way, it can damage your body (e.g., as hypertension can). A stress
reliever (e.g., a new hobby) can lower hypertension, but it has to be done
daily, and it has to be something you actually like doing.
The 80/20 rule: In some ways it doesn't matter what the new
hobby is. Whatever it is, getting started with it is 80% of the way to its
helping you. Making the appointment for a neurological test provides immediate
relief.
Dr. Sapolsky dispels another myth (the “executive stress
syndrome”): A higher ranking executive is more prone to stress. In the corporate
world, people at the top are not
stressed. It's middle management that is stressed. The highest level people have
control. Two important factors in enjoying one’s work: Doing what I love and
having some surprises in the job. That’s the right kind of stress. Two
important factors in stress management:
that the stress is not extreme and that it is not transient. It’s a benevolent
relinquishment of control.
One final thought: BDNF, a neurotrophic factor in brain, is
turning out to be important in mood and memory.
