Prediction mechanisms in motor and auditory areas and their role in sound perception and language understanding

Abstract

Is the meaning of an expected stimulus manifest in brain activity even before it appears? Although theories of predictive coding see anticipatory activity as crucial for the understanding of brain function, few studies have explored neurophysiologically manifest semantic predictions. Here, we report predictive negative-going potentials before the onset of action (i.e. whistle and hand clap) and non-action (i.e. pure tone, water drop) sounds. These prediction potentials (PP) indexed the meaning of action-related sounds. Dependent on the body-part-relationship of sound stimuli, neural sources were relatively more prominent in dorsal or ventral motor areas. In contrast, meaningless sounds (pure tones) activated predictive sources in temporal areas close to the auditory cortex; complex environmental sounds induced an anticipatory positivity broadly distributed over the scalp. We also found a systematic relationship between predictive activity and a Mismatch Negativity (MMN) like response to unexpected meaningful words which were presented as rare deviant stimuli amongst frequently repeated sounds. This deviant-elicited potential indexed semantic priming between action sounds and action-related words and semantic mismatch (prediction error). These results suggest a systematic link between perceptual/semantic prediction and matching mechanisms in the processing of sounds and words.