An accumulator model for spontaneous neural activity prior to self-initiated movement
An accumulator model for spontaneous neural activity prior to self-initiated movement
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DOI：
10.1073/pnas.1210467109
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发表时间：
2012-10-16
影响因子：
11.1
通讯作者：
Dehaene, Stanislas
中科院分区：
文献类型：
--
作者：
Schurger, Aaron;Sitt, Jacobo D.;Dehaene, Stanislas
在锁定到运动开始的平均时间内，神经元活动的逐渐积累被称为“准备就绪潜力”，可靠地先于自愿的自我发起运动。据推测，这一集结反映了行动计划和准备的最后阶段。在这里，我们对运动前的积聚提出了不同的解释。我们使用一个漏水的随机累加器来模拟在一个任务中“何时”移动的神经决策，在这个任务中，没有特定的时间提示，只有一般的命令，在几秒钟的未指定延迟后产生一个移动。根据我们的模型，当产生运动的必要性较弱时，决定阈值被越过导致运动的准确时刻在很大程度上由神经元活动的自发阈值下波动决定。运动开始的时间锁定确保了这些波动在平均情况下表现为神经元活动的渐进式指数增加。我们的模型考虑了从执行任务的人类受试者那里记录下来的行为和脑电数据，并做出了一个特定的预测，我们在第二次脑电实验中证实了这一预测：对时间上不可预测的干扰做出快速反应之前，应该在中断本身很久之前就开始缓慢的负向电压偏转，即使受试者在那个特定时刻没有准备移动。
A gradual buildup of neuronal activity known as the "readiness potential" reliably precedes voluntary self-initiated movements, in the average time locked to movement onset. This buildup is presumed to reflect the final stages of planning and preparation for movement. Here we present a different interpretation of the premovement buildup. We used a leaky stochastic accumulator to model the neural decision of "when" to move in a task where there is no specific temporal cue, but only a general imperative to produce a movement after an unspecified delay on the order of several seconds. According to our model, when the imperative to produce a movement is weak, the precise moment at which the decision threshold is crossed leading to movement is largely determined by spontaneous subthreshold fluctuations in neuronal activity. Time locking to movement onset ensures that these fluctuations appear in the average as a gradual exponential-looking increase in neuronal activity. Our model accounts for the behavioral and electroencephalography data recorded from human subjects performing the task and also makes a specific prediction that we confirmed in a second electroencephalography experiment: Fast responses to temporally unpredictable interruptions should be preceded by a slow negative-going voltage deflection beginning well before the interruption itself, even when the subject was not preparing to move at that particular moment.