Department of Brain and Cognitive Sciences and McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
J Neurophysiol. 2012 Jun;107(11):3144-54. doi: 10.1152/jn.00477.2011. Epub 2012 Mar 28.
Neurons in the primary motor cortex (M1) have been shown to have persistent, memory-like activity following adaptation to altered movement dynamics. However, the techniques used to study these memory traces limited recordings to only single sessions lasting no more than a few hours. Here, chronically implanted microelectrode arrays were used to study the long-term neuronal responses to repeated experience with perturbing, velocity-dependent force fields. Force-field-related neuronal activity within each session was similar to that found previously. That is, the directional tuning curves of the M1 neurons shifted in a manner appropriate to compensate for the forces. Next, the across-session behavior was examined. Long-term learning was evident in the performance improvements across multiple force-field sessions. Correlated with this change, the neuronal population had smaller within-session spike rate changes as experience with the force field increased. The smaller within-session changes were a result of persistent across-session shifts in directional tuning. The results extend the observation of memory traces of newly learned dynamics and provide further evidence for the role of M1 in early motor memory formation.
初级运动皮层（M1）中的神经元在适应运动动力学变化后会产生持久的、类似记忆的活动。然而，用于研究这些记忆痕迹的技术将记录限制在仅持续几个小时的单个会话中。在这里，慢性植入的微电极阵列用于研究重复经历扰动、速度相关力场时的长期神经元反应。每个会话中与力场相关的神经元活动与之前发现的相似。也就是说，M1 神经元的方向调谐曲线以适当的方式移动以补偿力。接下来，检查了跨会话的行为。在多次力场会话中，性能的提高表明存在长期学习。与这种变化相关的是，随着对力场经验的增加，神经元群体的会话内尖峰率变化变小。会话内变化较小是由于方向调谐的跨会话持续变化。结果扩展了对新学习动力学的记忆痕迹的观察，并为 M1 在早期运动记忆形成中的作用提供了进一步的证据。
