Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, People's Republic of China.
BMC Neurosci. 2012 May 30;13:55. doi: 10.1186/1471-2202-13-55.
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.
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.
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.
我们自身行为产生的感觉结果与外部产生的感觉刺激不同。本事件相关电位（ERP）研究检查了相对于外部触发刺激的自我触发刺激的神经反应，作为运动行为和刺激开始之间的延迟的函数。在维持元音发声的同时，受试者点击鼠标并在声音听觉反馈中听到音高转换刺激（PSS），延迟时间为 0 毫秒（可预测）或 500-1000 毫秒（不可预测）。在数据分析中，对鼠标点击产生的运动效应进行了校正。对于外部触发条件，在发声开始后 500-1000 毫秒，计算机发出 PSS。
与不可预测的外部触发 PSS 相比，可预测的自我触发 PSS 的 P2 反应明显受到抑制，而当自我触发 PSS 的时间不可预测时，P2 反应则出现增强效应。
这些发现表明，刺激传递相对于运动行为的时间可预测性对自我触发刺激的神经反应有影响。与外部触发刺激相比，当刺激传递的时间可预测或不可预测时，自我触发刺激的反应受到抑制或增强。本研究中不可预测的自我触发刺激的增强效应支持这样一种观点，即自我产生的动作的感觉抑制可能主要是由刺激时间的准确预测引起的，而不是与运动相关的非特异性抑制。
