Alaverdashvili Mariam, Foroud Afra, Lim Diana H, Whishaw Ian Q
Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada.
Behav Brain Res. 2008 Apr 9;188(2):281-90. doi: 10.1016/j.bbr.2007.11.007. Epub 2007 Nov 19.
Trauma or stroke to motor cortex (MtCx) results in motor impairments that include movements of the contralateral forelimb in reaching for food that is to be placed in the mouth for eating (skilled reaching). In the rat, post-lesion recovery of success is incomplete and achieved using compensatory movements. A striking and puzzling feature of post-lesion performance is an increase in the numbers of reaching attempts. Whereas successful movements, whether normal or compensatory, have been extensively described, there has been no previous analysis of the movements comprising reach attempts, especially those that are unsuccessful. Here, rats pretrained in a single pellet reaching task received MtCx stroke via pial removal contralateral to the preferred-for-reaching forelimb. They then received daily physical rehabilitation and assessment in reaching. In addition to conventional end-point measures of performance, reaching behavior was evaluated by a new measure, gestures, derived from Laban Movement Analysis. Gestural analysis describes all non-weight bearing limb movements and so can document movements not explicitly directed to, or successful in, grasping food. In the acute post-stroke period, MtCx rats made few gestures, but thereafter gesture number escalated with recovery time, and eventually exceeded preoperative levels. Gestures were frequently repetitive and included combinations not used prior to stroke. The escalation in gestures number with recovery training suggests that excessive and inappropriate gestures may represent motor habits that substitute for, and compete with, successful movements. This description of "learned baduse" furthers the understanding of MtCx contributions to skilled movements and could potentially contribute to the modification of rehabilitative strategies for the treatment of stroke.
运动皮层（MtCx）受到创伤或中风会导致运动障碍，包括对侧前肢在抓取食物并放入口中进食（熟练抓取）时的运动。在大鼠中，损伤后成功恢复并不完全，且是通过代偿性运动实现的。损伤后表现的一个显著且令人困惑的特征是抓取尝试次数增加。尽管成功的运动，无论是正常的还是代偿性的，都已有广泛描述，但此前尚未对构成抓取尝试的运动进行分析，尤其是那些未成功的运动。在此，在单粒食物抓取任务中预先训练的大鼠，通过去除其偏好抓取前肢对侧的软脑膜接受MtCx中风处理。然后它们每天接受物理康复治疗并进行抓取评估。除了传统的性能终点测量外，还通过一种源自拉班动作分析的新测量方法——手势，来评估抓取行为。手势分析描述了所有非负重肢体运动，因此可以记录未明确指向或成功抓取食物的运动。在中风后的急性期，MtCx大鼠做出的手势很少，但此后手势数量随着恢复时间增加，最终超过术前水平。手势经常重复，且包括中风前未使用过的组合。随着恢复训练手势数量的增加表明，过度和不适当的手势可能代表了替代并与成功运动竞争的运动习惯。这种对“习得性误用”的描述进一步加深了对MtCx对熟练运动贡献的理解，并可能有助于改进中风治疗的康复策略。
