Arousal is a physiological and psychological state of being awake. It involves the activation of the
reticular activating systemin the brain stem, the autonomic nervous systemand 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.
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 responseand 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. Later research suggest it is most likely that extroverts and introverts have different "arousability". Their baseline arousal level is the same, but the response to stimulation is different. [Randy J. Larsen, David M Buss; "Personality psychology, domains of knowledge about human nature", McGraw Hill, 2008]
The Yerkes-Dodson Law states that there is a relationship between arousal and task performance, essentially arguing that there is an optimal level of arousal for performance, and too little or too much arousal can adversely affect task performance. One interpretation of the Yerkes-Dodson Law is the Easterbrook Cue-Utilisation hypothesis. Easterbrook states that an increase of arousal leads to a decrease in number of cues that can be utilised. (Easterbrooke, 1959).
Abnormally Increased Behavioral Arousal
This is a state caused by withdrawal from
alcoholor barbiturates, acute encephalitis, head traumaresulting in coma, partial seizuresin epilepsy, metabolic disordersof electrolyteimbalance, Intra-cranial space- occupying lesions, Alzheimer's disease, rabies, hemispheric lesions in stroke and multiple sclerosis (2001).
Anatomically this is a disorder of the
limbic system, hypothalamus, temporal lobes, amygdalaand frontal lobes(2001). It is not to be confused with mania.
Mirr, Michelne Pheifer. "Abnormally Increased Behavioral Asrousal" Cris Stewart- Amidei and Joyce A. Kunkel. Neuroscience Nursing: Human Response to Neurologic Dysfunction. W. B. Sunders Philadelphia: PA, 2001
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