FRONTAL LOBE AND CEREBRAL CONTROL OF ADAPTIVE SPATIAL/MOTOR BEHAVIOR

这个项目的目标是阐明 认知信息处理在计划阶段的基础 空间运动行为。单个神经元的神经生理记录 活动进行时，猴子进行多方向， 预先由视觉信号指示的到达动作的顺序。这 设计与运动规划相关的孤立神经元活动 与动作执行有关。灵长类的三个主要亚类 对额叶进行研究，以了解其功能作用和 各自的特色化：初级运动皮质(M1)，背侧前运动 皮质(PMD)和辅助运动区(SMA)。 在M1和SMA中，大多数神经元的放电与 动作执行。这些神经元的空间调谐活动 传达有关运动运动学的信息，如运动方向 和幅度或目标位置的空间属性 运动终点。在PMD中，大多数神经元在 运动规划响应指示运动的视觉信号 即将到来的运动。这代表了工作中的编码和存储 记忆执行动作所需的信息以进行记忆 空间目标。检测PMD神经元活动与 记忆指示两级到达运动的指令 其执行的正确顺序。在25%的PMD神经元中 活动被发现编码了记忆到达的空间属性 独立于第一个或第二个移动段的移动 奉命行事。这些单元似乎可以可靠地对空间进行编码 将每个运动片段的各个方面转换成空间的特定部分。在……里面 相比之下，在75%的PMD细胞中，神经元反应优先编码 所记忆的教学信息与一个片段相关 按顺序到达的动作，通常是第一个。对于一个随机移动 序列，PMD神经元的空间调谐反应不同于常量 视觉信号指示第一或第二动作的规划 细分市场。因此，PMD像元活动对即将到来的空间属性进行编码 移动到太空中，并包含关于正确的 动作的顺序。 对于由固定的 空间规则，例如，彼此相对的目标，空间调谐的PMD 对第一个反应，活性普遍增强，而抑制。 响应于第二视觉指令。因为同样的视觉效果 使用信号来指导具有固定或随机空间的试验 规则，在PMD中记录的不同神经元反应是 归因于有效的空间规则。因此，PMD神经元是 参与准备进入太空的伸展运动，发出一种 对运动运动学的空间属性进行编码的信号 目标端点，发出预期移动序列的顺序的信号，以及 最后，动作准备过程中的差异化放电 由固定的空间规则预测的序列。

The goal of this project is to elucidate the neural mechanisms that underlie cognitive information processing during the planning stages of spatial-motor behavior. Neurophysiological recordings of single neuronal activity were undertaken as monkeys performed multidirectional, sequenced reaching movements pre-instructed by visual signals. This design isolated neuronal activity related to movement planning from that related to movement execution. Three major subdivisions of the primate frontal lobe were studied in order to understand the functional role and specialization of each: The primary motor cortex (M1), dorsal premotor cortex (PMd) and supplementary motor area (SMA). In M1 and SMA, the majority of neurons discharged in relation to movement execution. The spatially tuned activity of these neurons conveys information as to movement kinematics such as movement direction and amplitude or to spatial attributes of the target location and movement end-point. In PMd the majority of neurons discharge during movement planning in response to the visual signals which instruct the impending movement. This represents the encoding and storage in working memory of information required to execute movements to remembered spatial targets. PMd neuronal activity was examined in relation to the memorization of instructions signaling a two-stage reaching movement and the proper sequence of its execution. In 25% of PMd neurons this activity was found to encode spatial attributes of remembered reaching movements independent of whether the first or second movement segment was instructed. These cells appear to reliably encode the spatial aspects of every movement segment into a specific part of space. In contrast, in 75% of PMd cells, neuronal responses preferentially encode the remembered instructional information related to one segment of a sequenced reaching movement, usually the first. For a random movement sequence, spatially tuned responses of PMd neurons differ if a constant visual signal instructs planning of the first or second movement segment. Thus, PMd cell activity encodes spatial attributes of impending movements into space and incorporates information as to the correct sequence of movements. For movement sequences instructed by visual signals described by a fixed spatial rule, e.g., targets opposite each other, spatially tuned PMd activity was generally enhanced in response to the first and suppressed in response to the second visual instruction. Since the same visual signals were used to instruct trials with either fixed or random spatial rules, the differential neuronal responses recorded in PMd are attributable to the spatial rule in effect. Thus, PMd neurons are involved in the preparation of reaching movements into space, emit a signal that encodes spatial attributes of either movement kinematics or target endpoints, signal the order of an intended movement sequence, and finally, discharge differentially during the preparation of movement sequences predicted by a fixed spatial rule.