Dantzer R
J Anim Sci. 1986 Jun;62(6):1776-86. doi: 10.2527/jas1986.6261776x.
Stereotypies are repetitive actions that are fixed in form and orientation and serve no obvious purpose. Their occurrence in farm animals submitted to intensive husbandry has been interpreted to indicate inadequate environmental design or welfare. Over recent years, detailed descriptive studies have led to a better understanding of the organization and development of stereotypies, particularly in pregnant sows housed in tether stalls. Stereotyped behaviors appear to emerge from elements of initial defensive reactions of animals to their environment. They develop via a progressive narrowing of the behavioral repertoire, until only self-directed behaviors are displayed. Pharmacological studies suggest that performance of stereotyped behavior depends on the brain dopamine systems that are involved in selection and initiation of motor movements. However, generalization of these data to natural stereotypies is doubtful. Recent evidence favors an involvement of brain opioid peptides in stereotyped behavior of sows, although the exact mechanisms remain unknown. Stereotypies are typically observed in situations of conflict or frustration. They have been claimed to have an adaptive function, either by providing self-generated sensory stimulation to compensate for the lack of environmental stimulation, or by allowing animals to discharge their tension or anxiety. However, there is little evidence in favor of either interpretation. On the basis of present knowledge, it is proposed that stereotyped activities gain strength because of the positive feedback effect of sensory stimulation on their underlying control systems, which leads to a progressive sensitization of these neural systems. Stereotypies would then be simply the outward expression of an activation of lower brain structures controlling motor behavior which occurs in the absence of normal inhibitory control by higher nervous functions.
刻板行为是形式和方向固定且无明显目的的重复性动作。在集约化养殖的农场动物中出现此类行为被解读为环境设计不佳或福利问题。近年来，详细的描述性研究使人们对刻板行为的组织和发展有了更好的理解，尤其是在限位栏中饲养的怀孕母猪身上。刻板行为似乎源于动物对其环境的初始防御反应元素。它们通过行为模式的逐渐缩小而发展，直到只表现出自发性行为。药理学研究表明，刻板行为的表现取决于参与运动选择和启动的大脑多巴胺系统。然而，将这些数据推广到自然刻板行为上是值得怀疑的。最近的证据表明脑阿片肽参与了母猪的刻板行为，尽管确切机制尚不清楚。刻板行为通常在冲突或受挫的情况下观察到。有人认为它们具有适应性功能，要么通过提供自我产生的感觉刺激来弥补环境刺激的不足，要么通过让动物释放紧张或焦虑情绪。然而，几乎没有证据支持这两种解释。根据目前的知识，有人提出刻板活动会增强，是因为感觉刺激对其潜在控制系统产生了正反馈效应，这导致这些神经系统逐渐敏感。那么，刻板行为仅仅是在缺乏高级神经功能正常抑制控制的情况下，控制运动行为的较低脑结构激活的外在表现。
