Stress and Imprudent Brain Function
Glucocorticoids don’t cause action potentials in amygdaloid neurons, don’t invent excitation. Instead they amplify preexisting excitation.
⇒ Amygdala
During a fearful situation the amygdala recruits the Hippocampus into remembering contextual information about the event (e.g., the amygdala remembers the thief’s knife, whereas the hippocampus remembers where the robbery occurred). Stress strengthens this recruitment, making the hippocampus a temporary fear-laden suburb of the amygdala.
Stress compromises other aspects of frontal cortical function. Working Memory is disrupted; in one study, prolonged administration of high glucocorticoid levels to healthy subjects impaired working memory into the range seen after frontal cortical damage. Glucocorticoids accomplish this by enhancing Norepinephrine signaling in the PFC so much that, instead of causing aroused focus, it induces chicken-with-its-head-cut-off cognitive tumult, and by enhancing disruptive signaling from the amygdala to the PFC.
Stress also desynchronizes activation in different frontocortical regions, which impairs the ability to shift attention between tasks. ⇒ dorsolateral PFC
During sustained stress, the amygdala processes emotional sensory information more rapidly and less accurately, dominates hippocampal function, and disrupts frontocortical function;
rather than creating aggression, stress and glucocorticoids increase sensitivity to social triggers of aggression; (b) this occurs most readily in individuals already predisposed toward aggression.
The more a baboon tends to displace aggression after losing a fight, the lower his glucocorticoid levels.
Stress biases us toward Egoismus, Selfishness and also decreases Empathy.
Females stress response involve a stronger component of Oxytocin secretion.
The more an organism has been aggressive, the less Testosterone is needed for future aggression.
see also
Tags: neurobiology science
Superlink: 051 ☣Neurobiology 050 🧠Neuroscience
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Erstellt: 11-05-22 14:18