Hlustík Petr, Solodkin Ana, Noll Douglas C, Small Steven L
Department of Neurology, University of Maryland, Baltimore, Maryland, USA.
J Clin Neurophysiol. 2004 May-Jun;21(3):180-91. doi: 10.1097/00004691-200405000-00006.
The authors studied motor behavior and primary motor (M1) and somatosensory (S1) cortical representations of movement during hand motor skill acquisition over 3 weeks. During four functional MRI sessions 1 week apart, subjects performed simple movements of single fingers and wrist, and a sequential movement of the middle three fingers, contrasted with rest. Half of the subjects practiced the sequential movement, whereas the other half practiced a gross motor task (squeezing a sponge). In both groups, motor performance gradually improved both on the practiced sequence and also on unrelated tests of general hand performance. Similarly, gradual expansion of active M1 and S1 areas was observed with the practiced sequence and with the unpracticed single-finger and wrist movements. Motor practice enhanced overlaps and sharing of cortex (significantly more so in the fine-skill group), preserving somatotopy and the overall extent of the hand representations. Even a limited amount of practice on a complex task can thus lead to both specific and nonspecific improvements in behavior and to expansion of M1 and S1 movement representations. Finally, the extent of active M1 and S1 was significantly correlated with out-of-scanner performance on sequential finger movement and may reflect the current motor ability of the individual.
作者研究了在为期3周的手部运动技能习得过程中运动行为以及运动在初级运动皮层（M1）和体感皮层（S1）的表征。在间隔1周的4次功能磁共振成像（fMRI）检查期间，受试者进行单个手指和手腕的简单运动，以及中间三个手指的连续运动，并与静息状态进行对比。一半受试者练习连续运动，而另一半练习一项粗大运动任务（挤压海绵）。在两组中，无论是在练习的序列上还是在一般手部表现的无关测试中，运动表现均逐渐改善。同样，随着练习序列以及未练习的单指和手腕运动，观察到M1和S1激活区域逐渐扩大。运动练习增强了皮层的重叠和共享（精细技能组中更为显著），保留了躯体定位以及手部表征的整体范围。因此，即使对一项复杂任务进行有限量的练习也可导致行为上的特异性和非特异性改善以及M1和S1运动表征的扩展。最后，M1和S1的激活范围与扫描仪外的连续手指运动表现显著相关，可能反映了个体当前的运动能力。
