Motor demand-dependent activation of ipsilateral motor cortex
Motor demand-dependent activation of ipsilateral motor cortex
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DOI：
10.1152/jn.00110.2014
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发表时间：
2014-08-15
影响因子：
2.5
通讯作者：
Parsons, Michael
中科院分区：
文献类型：
--
作者：
Buetefisch, Cathrin M.;Revill, Kate Pirog;Parsons, Michael
同侧初级运动皮层（M1）在复杂任务执行过程中手部运动控制中的作用仍存在争议。在单侧手功能的功能性（f）MRI研究中观察到双侧M1激活不一致。有两个因素限制了对这些数据的解释。在这些研究中，由于运动任务的性质不同，可以想象，M1的贡献与技能的要求不同。第二，大多数研究缺乏验证的一个严格的单方面执行的运动任务在获取成像数据。在这里，我们使用功能性磁共振成像来确定是否同侧M1活动取决于精度的要求，在指向任务中，精度变化定量，而运动轨迹保持不变。13名健康的参与者使用MRI兼容的操纵杆指向块设计中四种不同大小的目标。集群采集技术允许同时fMRI/EMG数据收集，并确认运动是严格的单边。性能的准确性随着目标的大小而增加。总体而言，指向任务显示激活对侧和同侧M1，延伸到对侧体感和顶叶区。目标大小依赖性激活差异被发现在同侧M1延伸到颞/顶叶交界处，在那里激活随着准确性的需求增加而增加。结果表明，同侧M1是积极的，在执行单侧运动任务，其活动是由精确的需求调制。
The role of ipsilateral primary motor cortex (M1) in hand motor control during complex task performance remains controversial. Bilateral M1 activation is inconsistently observed in functional (f) MRI studies of unilateral hand performance. Two factors limit the interpretation of these data. As the motor tasks differ qualitatively in these studies, it is conceivable that M1 contributions differ with the demand on skillfulness. Second, most studies lack the verification of a strictly unilateral execution of the motor task during the acquisition of imaging data. Here, we use fMRI to determine whether ipsilateral M1 activity depends on the demand for precision in a pointing task where precision varied quantitatively while movement trajectories remained equal. Thirteen healthy participants used an MRI-compatible joystick to point to targets of four different sizes in a block design. A clustered acquisition technique allowed simultaneous fMRI/EMG data collection and confirmed that movements were strictly unilateral. Accuracy of performance increased with target size. Overall, the pointing task revealed activation in contralateral and ipsilateral M1, extending into contralateral somatosensory and parietal areas. Target size-dependent activation differences were found in ipsilateral M1 extending into the temporal/parietal junction, where activation increased with increasing demand on accuracy. The results suggest that ipsilateral M1 is active during the execution of a unilateral motor task and that its activity is modulated by the demand on precision.