Contralesional neural plasticity and functional changes in the less-affected forelimb after large and small cortical infarcts in rats
Contralesional neural plasticity and functional changes in the less-affected forelimb after large and small cortical infarcts in rats
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DOI：
10.1016/j.expneurol.2006.05.003
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发表时间：
2006-10-01
影响因子：
5.3
通讯作者：
Jones, Theresa A.
中科院分区：
文献类型：
--
作者：
Hsu, J. Edward;Jones, Theresa A.
一些研究已经发现，单侧脑损伤在同侧、“较少受影响的”身体侧产生显著的缺陷。其他研究发现，这种损伤导致同侧肢体功能异常，并促进了对侧运动皮层中由团队诱导的神经可塑性变化。本研究的目的是确定这些影响是否共存和/或随病变严重程度而变化。在感觉运动皮层（SMC）或假手术的小或大的单侧缺血性病变后，成年雄性大鼠训练20天以获得运动任务，熟练地达到食物，首次与同病前肢。运动模式的分析表明病灶大小依赖性的同病灶异常的把握，检索和释放食物颗粒。尽管有这些损伤，与假手术相比，病变组的成功率显著增加，瞄准错误减少。表现最好的大鼠与小病变，有更多的轻微同侧损伤。与假手术组相比，损伤对侧运动皮质和训练肢体的微管相关蛋白2（MAP 2）和N-甲基-D-天冬氨酸受体亚单位I（NMDAR 1）免疫反应阳性树突密度显著增加。这些影响与达成绩效相关。因此，增强运动技能学习的“较少受影响的”前肢和对侧病变的神经可塑性变化是静音后，较大的病变和共存的同病灶的损害。这些影响可能与去神经诱导的对侧皮层神经重构有关，这既破坏了先前存在的运动记忆痕迹，又有利于建立新的运动记忆痕迹。(c)2006爱思唯尔公司All rights reserved.
Some studies have found that unilateral cerebral damage produces significant deficits in the ipsilesional, "less-affected", body side. Other studies have found that such damage results in a paradoxical hyperfunctionality of the ipsilesional body side and a facilitation of teaming-induced neuroplastic changes in the contralesional motor cortex. The purpose of this study was to determine whether these effects co-exist and/or vary with lesion severity. After small or large unilateral ischemic lesions of the sensorimotor cortex (SMC) or sham operations, adult male rats were trained for 20 days to acquire a motor task, skilled reaching for food, for the first time with the ipsilesional forelimb. Analyses of movement patterns indicated lesion-size-dependent ipsilesional abnormalities in grasping, retrieving and releasing food pellets. Despite these impairments, success rates were significantly increased and aiming errors reduced in lesion groups compared with sham operates. Performance was best in rats with small lesions that had more minor ipsilesional impairments. In the motor cortex contralateral to the lesion and trained limb, there were significant increases in the density of dendrites immunoreactive for microtubule-associated protein-2 (MAP2) and of N-methyl-D-aspartate receptor subunit I (NMDAR1) immumoreactivity compared with sham operates. These effects were correlated with reaching performance. Therefore, enhanced motor skill learning in the "less-affected" forelimb and contralesional neuroplastic changes are muted after larger lesions and co-exist with ipsilesional impairments. These effects may be related to a denervation-induced neural restructuring of the contralesional cortex that both disrupts pre-existing motor engrams and facilitates the establishment of new ones. (c) 2006 Elsevier Inc. All rights reserved.