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4284850
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This explains context-dependent craving in addiction.93 Suppose an alcoholic has been clean and sober for years. Return him to where the alcohol consumption used to occur (e.g., that rundown street corner, that fancy men's club), and those potentiated synapses, those cues that were learned to be associated with alcohol, come roaring back into action, dopamine surges with anticipation, and the craving inundates.
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Robert M. Sapolsky |
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0e12657
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If by adolescence limbic, autonomic, and endocrine systems are going full blast while the frontal cortex is still working out the assembly instructions, we've just explained why adolescents are so frustrating, great, asinine, impulsive, inspiring, destructive, self-destructive, selfless, selfish, impossible, and world changing. Think about this--adolescence and early adulthood are the times when someone is most likely to kill, be killed, le..
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Robert M. Sapolsky |
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b323bbf
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As Beck and other cognitive therapists have emphasized, much of what constitutes a depression is centered around responding to one awful thing and overgeneralizing from it--cognitively distorting how the world works.
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Robert M. Sapolsky |
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83e9563
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Remapping occurs regularly throughout the brain in the absence of injury. My favorite examples concern musicians, who have larger auditory cortical representation of musical sounds than do nonmusicians, particularly for the sound of their own instrument, as well as for detecting pitch in speech; the younger the person begins being a musician, the stronger the remapping.15 Such remapping does not require decades of practice, as shown in beau..
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Robert M. Sapolsky |
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142e9a6
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Dopamine is not just about reward anticipation; it fuels the goal-directed behavior needed to gain that reward; dopamine "binds" the value of a reward to the resulting work. It's about the motivation arising from those dopaminergic projections to the PFC that is needed to do the harder thing (i.e., to work). In other words, dopamine is not about the happiness of reward. It's about the happiness of pursuit of reward that has a decent chance ..
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Robert M. Sapolsky |
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31cd014
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So if whites see a black face shown at a subliminal speed, the amygdala activates.10 But if the face is shown long enough for conscious processing, the anterior cingulate and the "cognitive" dlPFC then activate and inhibit the amygdala. It's the frontal cortex exerting executive control over the deeper, darker amygdaloid response."
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Robert M. Sapolsky |
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04f3849
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As you study the trait in more environments, the heritability score will decrease. This is recognized by Bouchard: "These conclusions [derived from a behavior genetics study] can be generalized, of course only to new populations exposed to a range of environments similar to those studied."31" --
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Robert M. Sapolsky |
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70e8c41
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Suppose a person harmed people two generations ago; are this person's grandchildren obliged to help his victims' grandchildren? Subjects viewed a biological grandchild as more obligated than one adopted into the family at birth; the biological relationship carried a taint. Moreover, subjects were more willing to jail two long-lost identical twins for a crime committed by one of them than to jail two unrelated but perfect look-alikes--the fo..
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Robert M. Sapolsky |
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d34e5fc
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The single genetic variant identified that most powerfully predicted height explained all of 0.4 percent--four tenths of one percent--of the variation in height, and all those hundreds of variants put together explained only about 10 percent of the variation. Meanwhile, an equally acclaimed study did a GWAS regarding body mass index (BMI). Similar amazingness--almost a quarter million genomes examined, even more authors than the height stud..
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Robert M. Sapolsky |
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79816b4
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As emphasized in the last chapter, epigenetic changes can be multi-generational.8 Dogma was that all the epigenetic marks (i.e., changes in the DNA or surrounding proteins) were erased in eggs and sperm. But it turns out that epigenetic marks can be passed on by both (e.g., make male mice diabetic, and they pass the trait to their offspring via epigenetic changes in sperm).
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Robert M. Sapolsky |
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8231cf7
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Heritability of various aspects of cognitive development is very high (e.g., around 70 percent for IQ) in kids from high-socioeconomic status (SES) families but is only around 10 percent in low-SES kids. Thus, higher SES allows the full range of genetic influences on cognition to flourish, whereas lower-SES settings restrict them. In other words, genes are nearly irrelevant to cognitive development if you're growing up in awful poverty--pov..
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Robert M. Sapolsky |
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b27d83c
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Cab drivers use spatial maps for a living, and one renowned study showed enlargement of that part of the hippocampus in London taxi drivers. Moreover, a follow-up study imaged the hippocampus in people before and after the grueling multiyear process of working and studying for the London cabbie license test (called the toughest test in the world by the New York Times). The hippocampus enlarged over the course of the process--in those who pa..
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Robert M. Sapolsky |
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ff628a1
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This was based on studies of a rare disorder, congenital adrenal hyperplasia (CAH). An enzyme in the adrenal glands has a mutation, and instead of making glucocorticoids, they make testosterone and other androgens, starting during fetal life.
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Robert M. Sapolsky |
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1b8427a
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Amazingly, prison sentences for murderers have now been lessened in at least two cases because it was argued that the criminal, having the "warrior gene" variant of MAO-A, was inevitably fated to be uncontrollably violent. OMG."
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Robert M. Sapolsky |
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de202ff
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The subject is also fascinating because of the nature of the revisionism--neuroplasticity radiates optimism. Books on the topic are entitled The Brain That Changes Itself, Train Your Mind, Change Your Brain, and Rewire Your Brain: Think Your Way to a Better Life, hinting at the "new neurology"
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Robert M. Sapolsky |
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2b2157c
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Remarkably, the fetal brain generates far more neurons than are found in the adult. Why? During late fetal development, there is a dramatic competition in much of the brain, with winning neurons being the ones that migrate to the correct location and maximize synaptic connections to other neurons. And neurons that don't make the grade? They undergo "programmed cell death"--genes are activated that cause them to shrivel and die, their materi..
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Robert M. Sapolsky |
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ee95d05
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Axonal remapping in blind or deaf individuals is great, exciting, and moving. It's cool that your hippocampus expands if you drive a London cab. Ditto about the size and specialization of the auditory cortex in the triangle player in the orchestra. But at the other end, it's disastrous that trauma enlarges the amygdala and atrophies the hippocampus, crippling those with PTSD. Similarly, expanding the amount of motor cortex devoted to finger..
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Robert M. Sapolsky |
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a3a5ec7
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Having the low-activity version of MAO-A tripled the likelihood ... but only in people with a history of severe childhood abuse. And if there was no such history, the variant was not predictive of anything. This is the essence of gene/environment interaction. What does having a particular variant of the MAO-A gene have to do with antisocial behavior? It depends on the environment.
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Robert M. Sapolsky |
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f60f1bc
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While average finger number is an inherited trait, the heritability of finger number is low--genes don't explain individual differences much.
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Robert M. Sapolsky |
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3a640b8
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During sustained stress, the amygdala processes emotional sensory information more rapidly and less accurately, dominates hippocampal function, and disrupts frontocortical function; we're more fearful, our thinking is muddled, and we assess risks poorly and act impulsively out of habit, rather than incorporating new data.
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Robert M. Sapolsky |
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0f9a555
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Moreover, sustained stress and glucocorticoid exposure enhance LTP and suppress LTD in the amygdala, boosting fear conditioning, and suppress LTP in the frontal cortex. Combining these effects--more excitable synapses in the amygdala, fewer ones in the frontal cortex--helps explain stress-induced impulsivity and poor emotional regulation.
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Robert M. Sapolsky |
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8b21db9
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here's a highly simplified version of the next chapter's focus on genes: (a) each gene specifies the production of a specific type of protein; (b) a gene has to be "activated" for the protein to be produced and "deactivated" to stop producing it--thus genes come with on/off switches; (c) every cell in our bodies contains the same library of genes; (d) during development, the pattern of which genes are activated determines which cells turn i..
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Robert M. Sapolsky |
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a51a1a9
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Meaney and colleagues, one of the most cited papers published in the prestigious journal Nature Neuroscience. They had shown previously that offspring of more "attentive" rat mothers (those that frequently nurse, groom, and lick their pups) become adults with lower glucocorticoid levels, less anxiety, better learning, and delayed brain aging. The paper showed that these changes were epigenetic--that mothering style altered the on/off switch..
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Robert M. Sapolsky |
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78bcd6c
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Thus, adult behavior produces persistent molecular brain changes in offspring, "programming" them to be likely to replicate that distinctive behavior in adulthood.76"
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Robert M. Sapolsky |
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c71bdcc
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Hormonal responses to various fetal and childhood experiences have epigenetic effects on genes related to the growth factor BDNF, to the vasopressin and oxytocin system, and to estrogen sensitivity. These effects are pertinent to adult cognition, personality, emotionality, and psychiatric health. Childhood abuse, for example, causes epigenetic changes in hundreds of genes in the human hippocampus.
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Robert M. Sapolsky |
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1463617
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drugs that decrease "serotonergic tone" (i.e., decreasing serotonin levels or sensitivity to serotonin) increase impulsive aggression; raising the tone does the opposite. This generates some simple predictions--all of the following should be associated with impulsive aggression, as they will produce low serotonin signaling: a. Low-activity variants of the gene for tryptophan hydroxylase (TH), which makes serotonin b. High-activity variants ..
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Robert M. Sapolsky |
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7d973bd
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Obviously, a theme of this book is just how many things can go wrong in the body because of stress and how important it is for everyone to recognize this. However, it would be utterly negligent to exaggerate the implications of this idea. Every child cannot grow up to be president; it turned out that merely by holding hands and singing folk songs we couldn't end all war, and hunger does not disappear just by visualizing a world without it. ..
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Robert M. Sapolsky |
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6f85ee9
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the average level of happiness increases in old age; fewer negative emotions occur and, when they do, they don't persist as long. Connected to this, brain-imaging studies show that negative images have less of an impact, and positive images have more of an impact on brain metabolism in older people, as compared to young.
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Robert M. Sapolsky |
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cc61cde
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when it comes to the bread and butter of human misery, try a major depression. It can be life-threatening, it can destroy lives, demolish the families of sufferers. And it is dizzyingly common--the psychologist Martin Seligman has called it the common cold of psychopathology. Best estimates are that from 5 to 20 percent of us will suffer a major, incapacitating depression at some point in our lives, causing us to be hospitalized or medicate..
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Robert M. Sapolsky |
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42603cb
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Whenever you inhale, you turn on the sympathetic nervous system slightly, minutely speeding up your heart. And when you exhale, the parasympathetic half turns on, activating your vagus nerve in order to slow things down (this is why many forms of meditation are built around extended exhalations).
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Robert M. Sapolsky |
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db6c5ce
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Genes are rarely about inevitability, especially when it comes to humans, the brain, or behavior. They're about vulnerability, propensities, tendencies
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Robert M. Sapolsky |
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f80be18
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Our nights are filled with worries about a different class of diseases; we are now living well enough and long enough to slowly fall apart.
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stress-management
worries
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Robert M. Sapolsky |
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9a430df
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A major depression, these findings suggest, can be the outcome of particularly severe lessons in uncontrollability for those of us who are already vulnerable. This may explain an array of findings that show that if a child is stressed in certain ways--loss of a parent to death, divorce of parents, being a victim of abusive parenting--the child is more at risk for depression years later. What could be a more severe lesson that awful things c..
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Robert M. Sapolsky |
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bc24c35
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The health risk of poverty turns out to be a huge effect, the biggest risk factor there is in all of behavioral medicine--in other words, if you have a bunch of people of the same gender, age, and ethnicity and you want to make some predictions about who is going to live how long, the single most useful fact to know is each person's SES.
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Robert M. Sapolsky |
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648d942
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University of Cambridge.68 When compared with non-CAH girls, CAH girls do more rough-and-tumble play, fighting, and physical aggression. Moreover, they prefer "masculine" toys over dolls. As adults they score lower on measures of tenderness and higher in aggressiveness and self-report more aggression and less interest in infants. In addition, CAH women are more likely to be gay or bisexual or have a transgender sexual identity."
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Robert M. Sapolsky |
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a81cc41
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Words pack power and these definitions are laden with values, often wildly idiosyncratic ones. Here's an example, namely the ways I think about the word "competition": (a) "competition"--your lab team races the Cambridge group to a discovery (exhilarating but embarrassing to admit to); (b) "competition"--playing pickup soccer (fine, as long as the best player shifts sides if the score becomes lopsided); (c) "competition"--your child's teach..
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Robert M. Sapolsky |
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456509d
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Neuropsychologists are coming to recognize that there is a specialized subset of long-term memory. Remote memories are ones stretching back to your childhood--the name of your village, your native language, the smell of your grandmother's baking. They appear to be stored in some sort of archival way in your brain separate from more recent long-term memories. Often, in patients with a dementia that devastates most long-term memory, the more ..
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Robert M. Sapolsky |
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e3a43c3
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Importantly, maternal stress impacts fetal development. There are indirect routes--for example, stressed people consume less healthy diets and consume more substances of abuse. More directly, stress alters maternal blood pressure and immune defenses, which impact a fetus. Most important, stressed mothers secrete glucocorticoids, which enter fetal circulation and basically have the same bad consequences as in stressed infants and children. G..
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Robert M. Sapolsky |
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5f4daa1
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But in reality the brain is about circuits, about the patterns of functional connectivity among regions. The growing myelination of the adolescent brain shows the importance of increased connectivity.
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Robert M. Sapolsky |
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3d92913
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It is never really the case that stress makes you sick, or even increases your risk of being sick. Stress increases your risk of getting diseases that make you sick, or if you have such a disease, stress increases the risk of your defenses being overwhelmed by the disease.
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Robert M. Sapolsky |
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b189509
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What the data show: the fewer social relationships a person has, the shorter his or her life expectancy, and the worse the impact of various infectious diseases. Relationships that are medically protective can take the form of marriage, contact with friends and extended family, church membership, or other group affiliations.
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Robert M. Sapolsky |
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5b5240a
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The impact of social relationships on life expectancy appears to be at least as large as that of variables such as cigarette smoking, hypertension, obesity, and level of physical activity.
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Robert M. Sapolsky |
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55f0e80
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Interestingly, traumatic stress early in life (abuse, for example) greatly increases the risk of IBS in adulthood. This implies that childhood trauma can leave an echo of vulnerability, a large intestine that is hyperreactive to stress, long afterward.
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Robert M. Sapolsky |
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28890ff
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What Wilkinson and others have shown is that poverty is not only a predictor of poor health but, independent of absolute income, so is poverty amid plenty--the more income inequality there is in a society, the worse the health and mortality rates.
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Robert M. Sapolsky |