Arousal is a physiological and psychological state of being awake. It involves the activation of the reticular activating system in the brain stem, the autonomic nervous system and the endocrine system, leading to increased heart rate and blood pressure and a condition of sensory alertness, mobility and readiness to respond.
There are many different neural systems involved in what is collectively known as the arousal system. Four major systems originating in the brainstem, with connections extending throughout the cortex, are based on the brain's neurotransmitters, acetylcholine, norepinephrine, dopamine, and serotonin. When these systems are in action, the receiving neural areas become sensitive and responsive to incoming signals.
Importance
Arousal is important in regulating consciousness, attention, and information processing. It is crucial for motivating certain behaviours, such as mobility, the pursuit of nutrition, the fight or flight response and sexual activity (see Masters and Johnson's human sexual response cycle, where it is known as the arousal phase). It is also very important in emotion, and has been included as a part of many influential theories such as the James-Lange theory of emotion. According to Hans Eysenck, differences in baseline arousal level lead people to be either extraverts or introverts.
