Question

These are brief, acute changes in conscious experience and physiology that occur in response to a personally meaningful situation?

Answer 1

Acute changes have the structures that are required for conscious appreciation on stimulus.

Neuro physiology has conscious appreciation depends on integrity of the cortical structures that offers the waking system of brainstem itself with the functionality of intact.

Conscious appreciation is not a stable as well as permanent phenomenon.

In fact, it is subject to physiological dissolution having reason on presence of sleep "systems".