Lucchetti C, Bon L
Department of Biomedical Sciences and Advanced Therapies, Section of Physiology, University of Ferrara, Via Fossato di Mortara 17/19, 44100 Ferrara, Italy.
Exp Brain Res. 2001 Nov;141(2):254-60. doi: 10.1007/s002210100818.
A voluntary motor act, executed in response to a stimulus, requires both spatial and temporal computation. Even though electrophysiological and positron emission tomography (PET) investigations on humans suggest that SMA, medial prefrontal cortex and primary motor cortex play a role in temporal mechanisms, we have few data about neuronal time computation in the premotor cortex. The involvement of monkey premotor area (PM) in motor learning and cognitive processes, and the presence of buildup neurons, whose activity is closely related to the motor action, prompted us to investigate the involvement of these set-related neurons in the time domain. To this end we manipulated the duration of a pre-cue in a visuomotor task while recording unit activity. We found that, when the duration of the pre-cue was predictable and long (5 s), delay of the onset of cell activity in consecutive trials gradually increased. On the other hand, when the duration was unpredictable or predictable and short (1 s), this phenomenon could not be detected. The inconsistent discharge correlations with expected reward and attentional processes, and the specific discharge relationship to the time instruction, suggest that these buildup neurons reflect a learning process in the time domain.
一个响应刺激而执行的自主运动行为需要空间和时间计算。尽管针对人类的电生理和正电子发射断层扫描（PET）研究表明，辅助运动区、内侧前额叶皮层和初级运动皮层在时间机制中发挥作用，但我们关于运动前皮层中神经元时间计算的数据却很少。猴子运动前区（PM）参与运动学习和认知过程，以及存在与运动动作密切相关的增强神经元，促使我们研究这些与集合相关的神经元在时间域中的参与情况。为此，我们在记录单位活动时，在视觉运动任务中操纵了预提示的持续时间。我们发现，当预提示的持续时间是可预测的且较长（5秒）时，连续试验中细胞活动开始的延迟会逐渐增加。另一方面，当持续时间不可预测或可预测且较短（1秒）时，这种现象无法检测到。与预期奖励和注意力过程不一致的放电相关性，以及与时间指令的特定放电关系，表明这些增强神经元反映了时间域中的学习过程。
