The Generic Inhibitory Function Of Corollary Discharge In Motor Intention Stage

Motor-to-sensory transformation refers to the process of converting motor signals into sensory signals.Through motor-to-sensory transformation,animals can perceive their own movements and predict the sensory consequences of their actions,thereby controlling their movements more effectively and adapting to different survival environments.Corollary discharge(CD)are believed to play an important role in motor-to-sensory transformation and theoretically it can predict the sensory consequences of actions to achieve efficient motor and cognitive control.Previous researchers assumed that the predictive computation is realized via inhibiting sensory reafference in action execution stage.To achieve continuous control in the whole action course,inhibitory function ubiquitously on all potential sensory reafference when sensory consequences are not available prior to action execution stage.However,the temporal characteristics as well as functional characteristics of CD are unclear.The present study is interested in the following three issues—Which course of actions does CD begin to operate in? To what extent does the inhibitory function implement sensory processes? What is the neural computation mechanism of the inhibitory function?In experiment 1,we used a delayed articulation paradigm including three categories of auditory probes(speech sound,non-speech sound,and non-human sound).The results found that general preparation to articulation task(preparing to speak without knowing what to say)inhibited neural responses to each auditory probe,which suggests a generic inhibitory function of CD in the motor intention stage.Moreover,both phase coherence and power in low-frequency bands(1-8 Hz)were suppressed,which indicated that inhibition function of CD was mediated by decreasing response amplitude and increasing temporal variance to sensory processes.Furthermore,inhibition was stronger for human sounds than non-human sounds,hinting that the established motor-sensory associations modulated the generic inhibitory function of CD.In experiment 2,we asked participants to keypress to trigger sounds instead of articulation.Our results found that general preparation to keypress did not suppress neural responses to any sound,supporting the hypothesis that the inhibitory function of CD is restricted by the strength of motor-sensory association.We also found the classic action induced sensory attenuation—the action execution of keypress suppressed the subsequent auditory responses,suggesting that the inhibitory function of motor signal is getting stronger as throughout the course of actions.To sum up,the results of experiment 1 indicates that early in the motor intention stage,the general inhibitory function of CD implement on all types of sounds,realized by modulating the amplitude and timing of neural responses and related to the association strength of motor and auditory features.Experiment 2 further supports that the association strength between motor and auditory features restricts the general inhibitory function,in which the motor effector to trigger sounds is finger instead of organs of speech.These results suggest the granularity of corollary discharge’s functional and temporal characteristics mediates multifaceted neural computations in motor and cognitive control.