自主动作引起感知衰减的时间特征与机制

The Time Characteristics and Mechanism of Sensory Attenuation Induced by Voluntary Action

目的:自主动作可以引起感知衰减已经得到前期研究证实,但该现象的时间进程尚不明确,机制也存在争议。研究通过2个实验对上述问题进行探索。方法:实验1共纳入被试12人,使用随机动点运动一致性判断任务,结合信号检测论,探索感知衰减现象的时间进程;实验2共纳入被试14人,采用主观报告法对预激活与抑制假说进行验证。结果:实验1中,将动作执行前后450 ms共900 ms以每150 ms划分为一段,动作执行前300 ms至执行后150 ms的3段时间内,被试的辨别力d’在自主动作效果与刺激对应关系一致条件下显著降低(P均<0.05);其余3段时间内,被试的辨别力d’在自主动作效果与刺激对应关系一致与不一致条件下差异不显著(P均>0.05)。实验2中,被试在刺激强度低的条件下,对与自主动作效果一致的刺激的主观强度报告显著高于不一致的刺激(P<0.05);在刺激强度为高的条件下,对自主动作效果对应一致或不一致的刺激评分无显著差异(P>0.05)。结论:自主动作引起的感知衰减在动作执行前就已经发生,动作执行前的150 ms与执行后的300 ms是重要的时间节点。自主动作可以在两个节点内引起感知衰减,在其他时间无法引起感知衰减。自主动作所引起的感知系统的预激活是感知衰减的成因。

Objective:Previous studies have confirmed that voluntary actions can induce sensory attenuation,but the time course of this phenomenon is not clear and the mechanism is still controversial.Therefore,this study explores the above problems through two experiments.Methods:A total of 12 subjects participated in experiment 1 which explored the sensory attenuation time course of this phenomenon with the judgement task of motion direction of random dot kinematogram and signal detection theory.14 subjects participated in experiment 2.The hypothesis of pre-activation and suppression was verified by subjective reporting method.Results:In experiment 1,the action performed before and after 450 ms totally 900 ms was divided by every 150 ms.Between three periods of 300 ms before action performed and 150 ms after,the subjects of discrimination d'in voluntary action effect and stimulus correspondence consistent condition decreased significantly(all P<0.05),there is no significant difference between the other three time periods and consistency and inconsistency of stimulus correspondence(all P>0.05).In experiment 2,when the stimulus intensity was low,the subjective report intensity was significantly higher in consistent condition than in inconsistent condition(P<0.05).When the stimulus intensity was high,there was no significant difference in the subjective report intensity between consistent and inconsistent condition(P>0.05).Conclusions:The sensory attenuation induced by the voluntary action occurred before the execution of the action.150 ms before the execution and 300 ms after are key time nodes.The voluntary action can induce sensory attenuation within two nodes,but it cannot induce sensory attenuation at other time.The pre-activation of the perceptual system by voluntary action is the cause of sensory attenuation.