Effect of temporal predictability on the neural processing of self-triggered auditory stimulation during vocalization.
BACKGROUND
Sensory consequences of our own actions are perceived differently from the sensory stimuli that are generated externally. The present event-related potential (ERP) study examined the neural responses to self-triggered stimulation relative to externally-triggered stimulation as a function of delays between the motor act and the stimulus onset. While sustaining a vowel phonation, subjects clicked a mouse and heard pitch-shift stimuli (PSS) in voice auditory feedback at delays of either 0 ms (predictable) or 500-1000 ms (unpredictable). The motor effect resulting from the mouse click was corrected in the data analyses. For the externally-triggered condition, PSS were delivered by a computer with a delay of 500-1000 ms after the vocal onset.


RESULTS
As compared to unpredictable externally-triggered PSS, P2 responses to predictable self-triggered PSS were significantly suppressed, whereas an enhancement effect for P2 responses was observed when the timing of self-triggered PSS was unpredictable.


CONCLUSIONS
These findings demonstrate the effect of the temporal predictability of stimulus delivery with respect to the motor act on the neural responses to self-triggered stimulation. Responses to self-triggered stimulation were suppressed or enhanced compared with the externally-triggered stimulation when the timing of stimulus delivery was predictable or unpredictable. Enhancement effect of unpredictable self-triggered stimulation in the present study supports the idea that sensory suppression of self-produced action may be primarily caused by an accurate prediction of stimulus timing, rather than a movement-related non-specific suppression.
Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, People's Republic of China.
Zhaocong
Z
Chen
Xi
X
Chen
Peng
P
Liu
Dongfeng
D
Huang
Hanjun
H
Liu
D000161:Acoustic Stimulation; D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D056228:Feedback, Sensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010898:Pitch Perception / Q000502:physiology*; D011237:Predictive Value of Tests; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D013997:Time Factors; D014831:Voice; D055815:Young Adult