The interplay between action and somatosensory perception has been a focal point of research over the past decades. Generally, a forward model has been posited to predict the somatosensory outcomes of actions, suggesting that the unexpected absence of tactile feedback during action should give rise to prediction errors. While such omission responses have been documented in the auditory domain, it remains unclear to what extent this mechanism generalizes across different sensory modalities.
This study aimed to investigate action-induced somatosensory omission responses through EEG recordings in a total of 30 human subjects. Self-paced button presses were associated with somatosensory stimuli in 88% of trials, enabling a prediction of the stimulus, or in 50% of trials, precluding such prediction. In the 88% condition, the absence of the predicted stimulus evoked a complex neural response consisting of multiple components, which was unveiled through temporal principal component analysis.
The initial oN1 response indicates sensory sources similar to stimulus-evoked activity but originating outside the primary cortex. Subsequent oN2 and oP3 responses were similar to observations in the auditory domain, likely signify higher-order, modality-unspecific processes. Together, findings straightforwardly demonstrate somatosensory predictions during action and provide evidence for a partially modality-unspecific mechanism of prediction error processing.