Department of Kinesiology, University of Waterloo, Waterloo, Canada.
Neurosci Lett. 2010 Oct 22;484(1):81-5. doi: 10.1016/j.neulet.2010.08.025. Epub 2010 Aug 13.
In non-human primates area 5 is dominated by the representation of the hand and forelimb, and has direct connectivity with primary motor cortex (M1) implicating its role in the control of hand movements. To date, few studies have investigated the function of area 5 in humans or its connectivity with M1. Using paired-pulse TMS, the present study investigates the functional connectivity between putative area 5 within the medial superior parietal lobule and ispilateral M1 in humans. Specifically, the motor evoked potential (MEP) from the first dorsal interosseous muscle of the right hand was quantified with and without conditioning TMS stimuli applied to left-hemisphere area 5. The timecourse of functional connectivity was examined during cutaneous stimulation applied to the thumb and index finger and also during rest whereby no somatosensory processing demands were imposed. Results indicate that area 5 facilitates and inhibits the MEP at 6 and 40ms, respectively, during somatosensory processing. No net influence of area 5 on M1 output was observed during rest. We conclude that area 5 has a task-dependent and temporally specific influence on M1 output, and suggest that the interaction between these areas presents a novel path with which to alter the motor output, and possibly movement of hand muscles.
在非人类灵长类动物中，区域 5 主要代表手和前肢的运动，并且与初级运动皮层（M1）直接相连，这表明它在手运动控制中的作用。迄今为止，很少有研究调查人类区域 5 的功能或其与 M1 的连接。本研究使用成对脉冲 TMS 研究了内侧上顶叶内假定的区域 5 与同侧 M1 之间的功能连接。具体来说，通过量化右手第一背侧骨间肌的运动诱发电位（MEP），研究了在左侧半球区域 5 施加条件性 TMS 刺激时的功能连接。在拇指和食指的皮肤刺激期间以及在没有感觉处理要求的休息期间，检查了功能连接的时程。结果表明，在感觉处理期间，区域 5 分别在 6 和 40ms 时促进和抑制 MEP。在休息期间，区域 5 对 M1 输出没有净影响。我们得出结论，区域 5 在手运动控制中对 M1 输出具有任务依赖性和时间特异性的影响，并表明这些区域之间的相互作用提供了一种改变运动输出、可能改变手部肌肉运动的新途径。
