Neural discharge and local field potential oscillations in primate motor cortex during voluntary movements
Neural discharge and local field potential oscillations in primate motor cortex during voluntary movements
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DOI：
10.1152/jn.1998.79.1.159
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发表时间：
1998-01-01
影响因子：
2.5
通讯作者：
Gaál, G
中科院分区：
文献类型：
--
作者：
Donoghue, JP;Sanes, JN;Gaál, G
在两只警觉猴子的运动皮层中检查了“快速”或伽马带（20-80 Hz）局部场电位（LFP）振荡在代表神经元活动和编码运动行为中的作用。使用长期植入的微丝，我们在训练的手指用力或伸手运动期间、自然伸手和抓握期间以及安静坐姿期间同时记录了中央前回一组部位的 LFP 和单单位或多单位 (MU) 放电。我们评估了同一部位的振荡与任务相关放电的耦合、相对于受过训练和未经训练的运动的执行的振荡时间，以及跨运动皮层部位的振荡的时间同步性。对总共 16 个手臂部位（一只猴子 7 个部位，另一只猴子 9 个部位）的 LFP 和神经放电进行了检查，每个部位都显示出与运动相关的放电调节和手臂微刺激效应。在训练任务中，快速 LFP 和 MU 振荡最常发生在运动前延迟期间，在运动开始时停止。振荡的减少大致与与运动动作耦合的发射速率调制的出现一致。在此延迟期间，LFP 振荡与该部位同时记录的神经放电表现出“重叠”或“混合”关系。重叠的特点是神经放电增加和 LFP 振荡同时发生。对于混合模式，LFP 振荡的发作通常与放电减少的时期同时发生，但有时也会出现重叠。在准备过程中，这两种模式在运动皮层同时发生。通过运动抑制 LFP 是普遍存在的。从安静坐姿过渡到恢复任务表现时，快速振荡很快重新出现，表明与任务参与度相关，而不是延迟期间的一般运动不活动。与训练有素的运动相反，在未经训练的伸手过程中，快速振荡经常伴随着运动出现，但振荡发生不规律，并且与神经放电升高没有可靠的相关性。同步振荡发生在相距 5 毫米的位置，表明运动皮层中神经元和 LFP 信号的广泛耦合。振荡信号的广泛耦合与时间编码过程在运动皮层中运行的概念是一致的。然而，因为神经元放电和快速振荡的出现之间的关系可能会因行为条件而改变。它们必须反映与运动规划或准备功能结合的全局过程，但不反映神经元放电率中编码的运动动作的细节。
The role of "fast," or gamma band (20-80 Hz), local field potential (LFP) oscillations in representing neuronal activity and in encoding motor behavior was examined in motor cortex of two alert monkeys. Using chronically implanted microwires, we simultaneously recorded LFPs and single or multiple unit (MU) discharge at a group of sites in the precentral gyrus during trained finger force or reaching movements, during natural reaching and grasping, and during quiet sitting. We evaluated the coupling of oscillations with task-related firing at the same site, the timing of oscillations with respect to the execution of trained and untrained movement, and the temporal synchrony of oscillations across motor cortical sites. LFPs and neural discharge were examined from a total of 16 arm sites (7 sites in 1 monkey and 9 in the other), each showing movement-related discharge modulation and arm microstimulation effects. In the trained tasks, fast LFP and MU oscillations occurred most often during a premovement delay period, ceasing around movement onset. The decrease in oscillation roughly coincided with the appearance of firing rate modulation coupled to the motor action. During this delay, LFP oscillations exhibited either "overlapping" or "mixed" relationships with the simultaneously recorded neural discharge at that site. Overlap was characterized by coincident epochs of increased neural discharge and LFP oscillations. For the mixed pattern, episodes of LFP oscillation typically coincided with periods of diminished firing but overlap also sometimes appeared. Both patterns occurred concurrently across motor cortex during preparation; LFP suppression with motor action was ubiquitous. Fast oscillations reappeared quickly upon transition from quiet sitting to resumption of task performance, indicating an association with task engagement, rather than the general motor inaction of the delay period. In contrast to trained movements, fast oscillations often appeared along with movement during untrained reaching, but oscillations occurred erratically and were not reliably correlated with elevated neural discharge. Synchronous oscillations occurred at sites as much as 5 mm apart, suggesting widespread coupling of neurons and LFP signals in motor cortex. Widespread coupling of oscillatory signals is consistent with the concept that temporal coding processes operate in motor cortex. However, because the relationship between neuronal discharge and the appearance of fast oscillations may be altered by behavioral condition. they must reflect a global process active in conjunction with motor planning or preparatory functions, but not details of motor action encoded in neuronal firing rate.