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Behave: The Biology of Humans at our Best and Worst Books

Chapter 2: One Second Before

The Amygdala Main Role & Themes

  • The amygdala is playing a role both in aggression and facets of fear and anxiety. fear and aggression are not inevitably intertwined – not all fear causes aggression, and not all aggression is rooted in fear. fear typically increases aggression only in those already prone to it; among the subordinate who lack the option of expressing safely, fear does the opposite
  • The dissociation between fear and aggression is evident in violent psychopaths, who are the antithesis of fearful – both physiologically and subjectively they are less reactive to pain; their amygdalae are relatively unresponsive to typical fear evoking stimuli and are smaller than normal. this fits with the picture of psychopathic violence; it is not done in aroused reaction to provocation. Instead, it is purely instrumental, using others as a means to an end with emotionless, remorseless, reptilian indifference.
  • Fear and violence are not always connected at the hip. But at a connection is likely when the aggression evoked is reactive, frenzied, and flecked with spittle. In a world in which no amygdaloid neuron need be afraid and instead can sit under its vine and fig tree, the world is very likely to be a more peaceful place.

(PP 44)

The Frontal Cortex

  • Quick definition: The frontal cortex makes you do the harder thing when it’s the right thing to do. (PP 45)
  • Cognition: The ability to orchestrate thought and action in accordance with internal goals
  • Cognitive load: when we make the frontal cortex work hard – a tough working-memory task, regulating social behavior, or making numerous decisions while shopping. immediately afterward performance on different frontally dependent task declines. Likewise, during multitasking, where PFC (prefrontal cortex) neurons simultaneously participate in multiple activated circuits. Importantly, increase cognitive load on the frontal cortex, and afterward subjects become less prosocial – less charitable or helpful, more likely to lie. or increase cognitive load with a task requiring difficult emotional regulation, and subjects cheat more on their diets afterward.
  • Huntington’s disease
  • The frontal cortex is not fully developed in teens, thus not fully functional, which can cause the amygdala to be increasingly activated and the person would feel increasingly distressed
  • dlPFC and vmPFC
    • dlPFC: The decider of deciders, the most rational, cognitive, utilitarian, unsentimental part of the PFC. it’s the most recently evolved part of the PFC and the last part to fully mature. It mostly hears from and talks to other cortical regions (PP 54)
    • vmPFC: This is the frontocortical region that the visionary neuroanatomist Nauta made an honorary member of the limbic system because of its interconnections with it. Logically, the vmPFC is all about the impact of emption on decision making. And many of our best and worst behaviors involve interactions of the vmPFC with the limbic system and dlPFC
  • Antecedent and Response Focused strategies to control/hide emotions:
    • Response-focused is dragging the emotional horse back to the barn after it’s fled – you’re watching a horrific footage, feeling queasy, and you think, “Okay, is still, breathe slowly” Typically this causes even greater activation of the amygdala and sympathetic nervous system
    • Antecedent strategies generally work better, as they keep the barn door closed from the start. These are about thinking/feeling about something else (e.g. that great vacation), or thinking/feeling differently about what you’re seeing (reappraisals such as “this isn’t real; those are just actors”). And when done right, the PFC particularly the dlPFC, activates the amygdala and sympathetic nervous system are damped, and subjective distress decreases
    • Antecedent reappraisal is why placebos work. Thinking “my finger is about to be pricked by a pin”, activates the amygdala along with a circuit of pain-responsive brain regions, and the pin hurts. Be told beforehand that the hand cream being slathered on your finger is a powerful analgesic cream, and you think “my finger is about to be pricked by a pin, but this cream will block the pain”. The PFC activates, blunting activity in the amygdala and pain circuitry, as well as pain perception

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