Schettino Luis F, Adamovich Sergei V, Bagce Hamid, Yarossi Mathew, Tunik Eugene
Psychology Department, Lafayette College, Easton, Pennsylvania 18042.
Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, New Jersey 07102, and Department of Rehabilitation and Movement Science.
J Neurosci. 2015 Feb 4;35(5):2112-7. doi: 10.1523/JNEUROSCI.3000-14.2015.
Replanning ongoing movements following perturbations requires the accurate and immediate estimation of the motor response based on sensory input. Previous studies have used transcranial magnetic stimulation (TMS) in humans to demonstrate the participation of the anterior intraparietal sulcus (aIPS) and ventral premotor cortex (PMv) in visually mediated state estimation for grasping. Here, we test the role of parietofrontal circuits in processing the corrective responses to haptic perturbations of the finger during prehension. Subjects reached to grasp an object while having to compensate for a novel and unpredictable haptic perturbation of finger extension. TMS-based transient disruptions to the PMv and aIPS were delivered 0, 50, or 100 ms after the perturbation. TMS to the PMv delivered 50 ms after the perturbation (but not 0 or 100 ms, or in unperturbed trials) led to an overestimation of grasp aperture. No effects on grasp aperture were noted for the aIPS. Our results indicate that the PMv (but not aIPS) is involved in the deployment of the compensatory response in the presence of haptic perturbations during prehension. Our data also identify the time window of neural processing in the PMv when reprogramming occurs to be 50-100 ms following the perturbation onset.
在受到干扰后重新规划正在进行的动作需要基于感觉输入准确且即时地估计运动反应。先前的研究已在人类中使用经颅磁刺激（TMS）来证明顶内沟前部（aIPS）和腹侧运动前皮层（PMv）参与了视觉介导的抓握状态估计。在此，我们测试顶额叶回路在处理抓握过程中手指触觉干扰的纠正反应中的作用。受试者伸手去抓握一个物体，同时必须补偿手指伸展的一种新的、不可预测的触觉干扰。在干扰后0、50或100毫秒对PMv和aIPS进行基于TMS的短暂干扰。在干扰后50毫秒（而非0或100毫秒，或在未受干扰的试验中）对PMv施加TMS会导致抓握孔径估计过高。未观察到aIPS对抓握孔径有影响。我们的结果表明，在抓握过程中存在触觉干扰时，PMv（而非aIPS）参与了补偿反应的部署。我们的数据还确定了在干扰开始后50 - 100毫秒发生重新编程时PMv中神经处理的时间窗口。
