Cortical control of sequential motor behavior

我们的许多熟练行为涉及的不是单一的动作，而是一系列的动作。 人类的病变和成像研究，以及亚人类灵长类动物的神经记录都表明，额叶皮层的内侧运动区对运动序列的产生特别重要。 不太清楚的是不同区域的神经活动与序列表现的空间和时间特征之间的确切关系。 我们的总体论点是，更喙运动区代码的全球方面的序列生产，如序列顺序或完整的序列规范。 然而，在诸如SMA、尾侧扣带回和运动皮层等直接获得运动输出的区域中的神经元通过其方向特性的变化来反映序列。(1)确定运动皮层细胞的方向特性在多大程度上反映了过度学习运动序列的表现。 该假说是，在运动皮层的细胞序列生产过程中显示出动态重组的方向属性。 (2)确定SMA和前SMA中的神经活动与过度学习序列的空间和时间方面之间的关系。 该假设是，全球方面的序列生产将更常见的前SMA编码，而在SMA的神经活动将反映的神经元和序列参数的方向属性之间的相互作用。 (3)记录过度学习序列执行过程中扣带回运动区的神经活动。 该假说认为扣带运动区是顺序控制的皮质系统的一个组成部分。 使用的方法将是在高度训练的恒河猴的目标皮层区域中的标准多电极记录的方法，具有用于行为控制和监测的适当仪器。 我们的实验方法在几个重要方面与其他检查序列神经相关性的尝试不同：我们将使用利用序列表现固有的空间维度的行为任务，并且我们特别强调记录的神经元的空间属性的变化。

Many of our skilled behaviors involve not single actions but sequences of movements. Lesion and imaging studies in humans, in addition to neural recording in sub human primates have demonstrated that the medial motor areas in the frontal cortex are particularly important for the generation of motor sequences. What is less clear is the exact relation between neural activity in the different areas and the spatial and temporal features of sequence performance. Our general thesis is that the more rostral motor areas code for global aspects of sequence production such as serial order or complete sequence specification. Whereas neurons in areas with direct access to motor output such as the SMA, caudal cingulate, and motor cortex reflect sequences by changes in their directional properties. (1) To determine the extent to which the directional properties of cells in the motor cortex reflect aspects of the performance of over-learned motor sequences. The hypothesis is that cells in the motor cortex show a dynamic re-organization of directional properties during sequence production. (2) To determine the relation between neural activity in the SMA and pre-SMA and the spatial and temporal aspects of over-learned sequences. The hypothesis is that global aspects of sequence production will be more commonly coded in pre-SMA, while neural activity in SMA will reflect an interaction between the directional properties of the neurons and sequence parameters. (3) To record the neural activity in the cingulate motor areas during the performance of over-learned sequences. The hypothesis is that cingulate motor areas are an integral component of the cortical system for sequence control. The methods used will be those of standard multi-electrode recording in the target cortical areas of highly trained rhesus monkeys with appropriate instrumentation for behavioral control and monitoring. Our experimental approach differs from other attempts to examine the neural correlates of sequences in several important respects: we will use behavioral tasks which exploit the spatial dimension inherent in sequence performance and we place particular emphasis on changes in the spatial properties of the recorded neurons.