Erickson Crystal A, Gharbawie Omar A, Whishaw Ian Q
Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, 4401 University Drive, Lethbridge, Alta. T1K 3M4, Canada.
Behav Brain Res. 2007 May 16;179(2):208-18. doi: 10.1016/j.bbr.2007.02.004. Epub 2007 Feb 9.
The notion that shock or diaschisis is a distinctive stage in the recovery process following brain damage has played a formative role in the characterization of brain injury. For example, damage to the forelimb region of motor cortex results in an acute period of behavioural depression in skilled reaching and other skilled actions followed by improved performance mediated by compensatory movements. Whereas the progression of improvement and the use of compensatory movements in the chronic period of recovery is well-documented, temporal aspects of behaviour during the acute period of depression of behaviour are relatively unstudied. The present study examined the temporal scheduling of reach-attempts by rats attempting to gain single pellets of food from a shelf in a skilled reaching task. Pretrained rats received contralateral-to-the-pretrained limb forelimb motor cortex lesions. Control lesions included contralateral-to-the-pretrained limb parietal cortex lesions, or ipsilateral-to-the-pretrained limb motor cortex lesions. Frame-by-frame video analysis of behaviour showed a decrease in reaching attempts as a function of successive approaches and attempts to grasp the food over the first few postsurgical days in rats with contralateral-to-the-pretrained limb motor cortex lesions. A similar approach-dependent decrease in attempts did not occur after parietal or ipsilateral-to-the-pretrained limb motor cortex lesions. The decrease in responding occurred only during acute testing and was not observed in rats first tested after 8 days of postoperative recovery. The findings are discussed in relation to the ideas that: (1) the stroke subject is an active participant in modifying behaviour to cope with injury; (2) learned nonuse contributes to behaviour in the acute postinjury period following motor cortex injury; (3) diaschisis inadequately accounts for poststoke behaviour.
休克或远隔性机能障碍是脑损伤后恢复过程中的一个独特阶段，这一观念在脑损伤的特征描述中发挥了重要作用。例如，运动皮层前肢区域受损会导致熟练抓握及其他熟练动作出现行为抑制急性期，随后通过代偿性运动介导表现改善。虽然在慢性恢复期改善的进展和代偿性运动的使用已有充分记录，但行为抑制急性期的行为时间方面相对未被研究。本研究考察了大鼠在熟练抓握任务中从架子上获取单个食物颗粒时伸手尝试的时间安排。经过预训练的大鼠接受与预训练肢体对侧的前肢运动皮层损伤。对照损伤包括与预训练肢体对侧的顶叶皮层损伤，或与预训练肢体同侧的运动皮层损伤。行为的逐帧视频分析显示，在与预训练肢体对侧的运动皮层损伤的大鼠中，在术后最初几天，随着连续接近和尝试抓取食物，伸手尝试次数减少。在顶叶或与预训练肢体同侧的运动皮层损伤后，未出现类似的与接近相关的尝试次数减少。反应减少仅发生在急性测试期间，在术后恢复8天后首次测试的大鼠中未观察到。研究结果结合以下观点进行讨论：（1）中风患者是积极参与改变行为以应对损伤的参与者；（2）习得性废用导致运动皮层损伤后急性期的行为；（3）远隔性机能障碍不足以解释中风后的行为。
