Department of Biological Sciences, Faculty of Science, University of Calgary, Canada; Hotchkiss Brain Institute, University of Calgary, Canada.
Behav Brain Res. 2010 Dec 6;214(1):60-5. doi: 10.1016/j.bbr.2010.05.013. Epub 2010 May 22.
Kindling of the sensorimotor neocortex has been found to result in reorganization of the somatotopic map of movement representations as well as disruptions of skilled forelimb behaviours. It has been suggested that the repeated seizures induced during kindling altered motor maps, thereby disrupting the motor engram necessary for the production of skilled movements. However, kindling leads to neural changes other than those associated with repeated seizures, and the role of these comorbid effects is often overlooked. Our lab has developed a stimulation paradigm, which allows for the dissociation of the two main effects of kindling; repeated seizures and the reduction of afterdischarge (seizure) threshold. In the current study, we have utilized this paradigm to examine the effects of electrical stimulation on motor maps and skilled forelimb behaviour. We found that repeated seizures with no concomitant reduction of afterdischarge threshold resulted in large motor maps, as well as task specific deficits in skilled forelimb use and deficiencies in task acquisition. Rats that had reduced seizure thresholds and few seizures did not show alterations in map size or skilled forelimb use. These results suggest that movement disturbances following kindling are the result of repeated seizures, and not other stimulation-induced effects such as reduction of afterdischarge threshold. These results also corroborate the relationship between the integrity of movement representations and the ability to perform skilled motor tasks.
已发现，感觉运动新皮层的点燃会导致运动代表区的躯体图重组，以及熟练前肢行为的破坏。有人认为，在点燃过程中反复发生的癫痫发作改变了运动图，从而破坏了产生熟练运动所需的运动记忆。然而，点燃会导致除与反复癫痫发作相关的神经变化以外的其他变化，而这些合并效应的作用往往被忽视。我们的实验室开发了一种刺激范式，可以分离点燃的两个主要影响；反复癫痫发作和发作后放电（癫痫）阈值降低。在目前的研究中，我们利用这一范式研究了电刺激对运动图和熟练前肢行为的影响。我们发现，没有伴随发作后放电阈值降低的反复癫痫发作导致了大的运动图，以及熟练前肢使用的特定任务缺陷和任务获取的缺陷。那些发作阈值降低且发作次数较少的大鼠，其运动图大小或熟练前肢使用并未发生改变。这些结果表明，点燃后运动障碍是反复癫痫发作的结果，而不是其他刺激诱导的效应，如发作后放电阈值降低。这些结果还证实了运动代表区的完整性与执行熟练运动任务的能力之间的关系。
