"Master" Neurons Induced by Operant Conditioning in Rat Motor Cortex during a Brain-Machine Interface Task
"Master" Neurons Induced by Operant Conditioning in Rat Motor Cortex during a Brain-Machine Interface Task
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DOI：
10.1523/jneurosci.2744-12.2013
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发表时间：
2013-05-08
影响因子：
5.3
通讯作者：
Ego-Stengel, Valerie
中科院分区：
文献类型：
--
作者：
Arduin, Pierre-Jean;Fregnac, Yves;Ego-Stengel, Valerie
通过神经元皮质活动对假体的操作控制是实现脑机接口(BMI)的成功策略之一，通过BMI，受试者学习对目标定向运动施加意志控制。然而，目前尚不清楚诱导的大脑回路重组是否会优先影响在训练期间控制BMI执行器活动的条件神经元。在此，在头部固定行为大鼠的运动皮质中同时记录到多个细胞外单一单位。利用单个神经元的放电频率来控制一维执行器的位置。每次触发率超过预定义的阈值时，一个水瓶就会向老鼠移动，直到瓶子的累积位移允许动物喝水。经过一段时间的学习后，大多数(88%)的条件神经元在实验期间提高了它们的活动，以至于奖励的时间在不同阶段减少：实验开始后，条件神经元强烈、可靠和迅速地激发，尽管学习规则中没有明确的指令强制神经元做出快速反应。此外，条件性神经元比非条件性邻近神经元更早、更强烈地发出信号。在第一次训练中，只有高度条件化的神经元才能看到放电频率变异性的增加。这种可变性随后降低，而条件反射效应增加。这些发现表明，训练过程中的修改优先以被选择来控制BMI的神经元为目标，然后BMI充当“主”神经元，最终导致局部皮质网络中活动的重新配置。
Operant control of a prosthesis by neuronal cortical activity is one of the successful strategies for implementing brain-machine interfaces (BMI), by which the subject learns to exert a volitional control of goal-directed movements. However, it remains unknown if the induced brain circuit reorganization affects preferentially the conditioned neurons whose activity controlled the BMI actuator during training. Here, multiple extracellular single-units were recorded simultaneously in the motor cortex of head-fixed behaving rats. The firing rate of a single neuron was used to control the position of a one-dimensional actuator. Each time the firing rate crossed a predefined threshold, a water bottle moved toward the rat, until the cumulative displacement of the bottle allowed the animal to drink. After a learning period, most (88%) conditioned neurons raised their activity during the trials, such that the time to reward decreased across sessions: the conditioned neuron fired strongly, reliably and swiftly after trial onset, although no explicit instruction in the learning rule imposed a fast neuronal response. Moreover, the conditioned neuron fired significantly earlier and more strongly than nonconditioned neighboring neurons. During the first training sessions, an increase in firing rate variability was seen only for the highly conditionable neurons. This variability then decreased while the conditioning effect increased. These findings suggest that modifications during training target preferentially the neuron chosen to control the BMI, which acts then as a "master" neuron, leading in time the reconfiguration of activity in the local cortical network.