Dettmers C, Lemon R N, Stephan K M, Fink G R, Frackowiak R S
Wellcome Department of Cognitive Neurology, Leopold Müller Functional Imaging Laboratory, National Hospital for Neurology and Neurosurgery, London, UK.
Neuroreport. 1996 Sep 2;7(13):2103-10. doi: 10.1097/00001756-199609020-00008.
The aim of our study was to determine alterations of cerebral activity during prolonged static force exertion. Regional cerebral blood flow (rCBF) was measured using H2(15)O positron emission tomography (PET) while six male normal subjects pressed a morse-key with their right index finger with a constant force of 20% of their maximal voluntary contraction (MVC) for different periods of time (1.5-4.5 min). Exertion of static force led to activation which was at least as extensive as that during exertion of repetitive dynamic force pulses. Despite a considerable sense of fatigue and increased effort at the end of a 4.5 min key press, no compensatory changes of activity were detected in motor or sensory related structures. The right dorsolateral prefrontal cortex demonstrated a significant correlation between rCBF and duration of key-press, possibly reflecting processes over-riding fatigue. Prominent basal ganglia activation was demonstrated in this static force task, but not in a previous force task involving repetitive dynamic force pulses. This suggests that sustained exertion of a static force is an active process modulated, at least in part, by the basal ganglia.
我们研究的目的是确定长时间静态用力过程中大脑活动的变化。当六名男性正常受试者用右手食指以其最大自主收缩（MVC）的20%的恒定力量按压莫尔斯电键不同时间段（1.5 - 4.5分钟）时，使用H2(15)O正电子发射断层扫描（PET）测量局部脑血流量（rCBF）。静态用力导致的激活至少与重复动态力脉冲用力时一样广泛。尽管在4.5分钟按键结束时受试者有相当程度的疲劳感且用力增加，但在运动或感觉相关结构中未检测到活动的代偿性变化。右侧背外侧前额叶皮质的rCBF与按键持续时间之间存在显著相关性，这可能反映了克服疲劳的过程。在这个静态用力任务中显示出基底神经节明显激活，但在先前涉及重复动态力脉冲的用力任务中未出现这种情况。这表明持续的静态用力是一个至少部分由基底神经节调节的主动过程。
