Autonomic Activation

Abstract

Without Abstract Synonyms Autonomic arousal; Autonomic reactivity Definition Autonomic activation refers to an increase in the activity of the autonomic nervous system, the physical system responsible for nonconsciously maintaining bodily homeostasis and coordinating bodily responses. It is assessed by comparing autonomic values obtained during a test period to those obtained during a rest or baseline period. Baseline measures commonly are taken shortly before test periods. However, they can be taken well in advance of test periods or after them. Autonomic activation can pertain to neuronal activity or activity of visceral structures affected by it, such as the ones involved in circulation, respiration, and digestion. The distinction between neuronal activation and visceral structure activation is not trivial given that an increase in the activity of a visceral structure may be caused by a decrease in neuronal activity. For instance, increases in the frequency of the heart beat – which are often interpreted as signals of autonomic activation – can be due to reduced activity in the parasympathetic branch of the autonomic nervous system.