The auditory N1 suppression rebounds as prediction persists over time

The predictive coding model of perception proposes that neuronal responses reflect prediction errors. Repeated as well as predicted stimuli trigger suppressed neuronal responses because they are associated with reduced prediction errors. However, many predictable events in our environment are not isolated but sequential, yet there is little empirical evidence documenting how suppressed neuronal responses reflecting reduced prediction errors change in the course of a predictable sequence of events. Here we conceived an auditory electroencephalography (EEG) experiment where prediction persists over series of four tones to allow for the delineation of the dynamics of the suppressed neuronal responses. It is possible that neuronal responses might decrease for the initial predictable stimuli and stay at the same level across the rest of the sequence, suggesting that they reflect the predictability of the stimuli in terms of mere probability. Alternatively, neuronal responses might decrease for the initial predictable stimuli and gradually recover across the rest of the sequence, suggesting that factors other than mere probability have to be considered in order to account for the way prediction is implemented in the brain. We found that initial presentation of the predictable stimuli was associated with suppression of the auditory N1. Further presentation of the predictable stimuli was associated with a rebound of the component's amplitude. Moreover, such pattern was independent of attention. The findings suggest that auditory N1 suppression reflecting reduced prediction errors is a transient phenomenon that can be modulated by multiple factors.