neurolove:

Let’s talk a little about stress in the brain.  Most students have recently finished exams for the fall semester, and the holidays bring a whole new set of stressors as people deal with travel arrangements (and even family).

One way that stress manifests is by the systemic release of norepinephrine (also called noradrenaline).  In the brain, norepinephrine has widespread effects.  There are three main types of receptors for norepinephrine- alpha 2, alpha 1, and beta receptors.  I list them in this order because alpha 2 receptors require the least amount of norepinephrine to be active, alpha 1 require more, and beta require the most.  This means that alpha 2 receptors are most active in times without stress (when there are low levels of norepinephrine), while alpha 1 and beta are more active during stress.

Amygdala, the part of the brain that is very emotionally responsive and can provide “fight or flight” kind of reasoning, is mainly activated by activation of alpha 1 and beta receptors.  On the other hand, prefrontal cortex, which provides a lot of mental control and decision making, is mainly controlled by alpha 2 receptors and is deactivated by alpha 1 and beta receptors.  This means that during stress, prefrontal cortex will be less active and amygdala, which is more primitive and emotionally-driven, will take over.

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