Defining features, clinical conditions, and theoretical constructs of stereotyped movements.

Abstract

tereotyped behavior is a difficult concept to define. This difficulty is S not dissimilar to that faced in the accurate diagnosis of other movement disorders. Identification and classification can be hindered by a number of obstacles. In contrast to a paralysis of motor function or an incoordination of movement, the "material evidence" of a movement disorder is ephemeral and fleeting, occurring with variable frequency and characterized by morphologic variability. Some movement disorders are stimulus sensitive, activated by vocalization or motor activity. Most are exacerbated by emotional stress. In addition, the presence of movement disorders in the setting of psychiatric disease (e.g., schizophrenia, autism) combined with the existence of psychogenic movement disorders adds to the complexity of accurate diagnosis.The characteristics of a given movement disorder may not be unique to a specific disease process. For example, the chorea of Huntington's disease may not appear strikingly different from the chorea that occurs as a drug-induced side effect. Therefore, a given movement disorder may cross

Social buffering in adult male rhesus macaques (Macaca mulatta): Effects of stressful events in single vs. pair housing

“…The physiological basis for these behaviors is still not fully understood and may involve positive feedback mechanisms in lower brain structures that control motor activity [13]. Several neurotransmitters such as dopamine, acetylcholine, serotonin, and opioid peptides likely interact in the development of stereotypies, and hormones such as corticotropin‐releasing hormone are also thought to be responsible for the physiological correlates of stereotypic behavior [24, 38]. Because they arise both in settings that are stressful and in those that are understimulating, stereotypies may serve to either decrease arousal in situations of distress or increase arousal in environments that are lacking in complexity [38].…”

Beta-endorphin levels in longtailed and pigtailed macaques vary by abnormal behavior rating and sex

“…The persistence of behaviors that interfere with normal life, in some cases causing pain and suffering, has inspired various hypotheses. The self-stimulating properties of stereotypies may develop to increase arousal in unstimulating environments; or stereotyped behavior may occur during states of increased stress, serving as a coping mechanism by dissipating tension, frustration or anxiety; or both [13,47]. The long-term maintenance of abnormal behavior may result if the individual displaying it is somehow rewarded through its exhibition [34].…”