The Thalamus region of the brain gets sensory data. Parts of this is sent to Amygdala(emotional/irrational part of the brain) and parts to the neocortex(thinking/rational brain). If the Amygdala matches it with an earlier threat stimulus, then it activates a shortcut(HPA/hypothalmic-pituitary-adrenal axis) - and effectively takes over the brain overriding the rational area.
Published on May 12, 2021