Cortical control of sequential motor behavior

我们许多熟练的行为不是单一的动作，而是一系列的动作。在人类中的损伤和成像研究，除了在亚人类灵长类动物中的神经记录外，已经证明额叶皮质的内侧运动区对于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时空特征之间的确切关系。我们的一般论点是，更多的吻马达区域编码序列生产的全球方面，如序列订单或完整序列规范。而直接接触到运动输出的区域，如SMA、尾侧扣带回和运动皮质的神经元，则通过它们方向特性的变化来反映序列。(1)确定运动皮质细胞的方向性在多大程度上反映了过度学习的运动序列的表现。假设是运动皮质中的细胞在序列产生过程中表现出方向性的动态重组。(2)确定SMA和Pre-SMA中的神经活动与过度学习序列的空间和时间方面的关系。假设序列产生的全局方面将更常见地在SMA前编码，而SMA中的神经活动将反映神经元的方向性属性和序列参数之间的相互作用。(3)记录过度学习序列执行过程中扣带运动区的神经活动。假设扣带运动区是用于顺序控制的大脑皮层系统的组成部分。所使用的方法将是标准的多电极记录方法，在高度训练的恒河猴的目标皮质区域使用适当的仪器进行行为控制和监测。我们的实验方法在几个重要方面与其他检验序列神经相关性的尝试不同：我们将使用利用序列性能固有的空间维度的行为任务，我们特别强调记录的神经元空间属性的变化。

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.