Sensory suppression refers to the phenomenon that sensory input generated by our own actions, such as moving a finger to press a button to hear a tone, elicits smaller neural responses than sensory input generated by external agents. This observation is usually explained via the internal forward model in which an efference copy of the motor command is used to compute a corollary discharge, which acts to suppress sensory input. However, because moving a finger to press a button is accompanied by neural processes involved in preparing and performing the action, it is unclear whether sensory suppression is the result of movement planning, movement execution, or both. To investigate this, in two experiments, we compared ERPs to self-generated tones that were produced by voluntary, semivoluntary, or involuntary button-presses, with externally generated tones that were produced by a computer. In Experiment 1, the semivoluntary and involuntary button-presses were initiated by the participant or experimenter, respectively, by electrically stimulating the median nerve in the participant's forearm, and in Experiment 2, by applying manual force to the participant's finger. We found that tones produced by voluntary button-presses elicited a smaller N1 component of the ERP than externally generated tones. This is known as N1-suppression. However, tones produced by semivoluntary and involuntary button-presses did not yield significant N1-suppression. We also found that the magnitude of N1-suppression linearly decreased across the voluntary, semivoluntary, and involuntary conditions. These results suggest that movement planning is a necessary condition for producing sensory suppression. We conclude that the most parsimonious account of sensory suppression is the internal forward model.

感觉抑制是指由我们自己的行为产生的感觉输入，例如移动手指按下按钮来听到一个音调，引起比外部代理产生的感觉输入更小的神经反应的现象。这种观察通常通过内部前向模型来解释，其中运动命令的影响副本用于计算必然放电，从而抑制感官输入。然而，由于移动手指以按下按钮伴随着准备和执行动作所涉及的神经过程，因此尚不清楚感觉抑制是运动计划、运动执行还是两者兼而有之。为了对此进行研究，在两个实验中，我们将 ERP 与由自愿、半自愿或非自愿按钮按压产生的自发音调进行了比较，带有由计算机产生的外部生成的音调。在实验 1 中，参与者或实验者分别通过电刺激参与者前臂的正中神经来启动半自愿和非自愿按钮按压，而在实验 2 中，通过对参与者的手指施加手动力。我们发现，与外部产生的音调相比，由自愿按下按钮产生的音调引起的 ERP 的 N1 分量更小。这被称为 N1 抑制。然而，由半自愿和非自愿按钮按压产生的音调并没有产生显着的 N1 抑制。我们还发现，在自愿、半自愿和非自愿条件下，N1 抑制的程度呈线性下降。这些结果表明运动计划是产生感觉抑制的必要条件。我们得出结论，对感觉抑制最简洁的解释是内部前向模型。