The duration of a neuronal trace of an auditory stimulus as indicated by event-related potentials.

Event-related brain potential studies have revealed a component called the mismatch negativity (MMN) in response to occasional deviant stimuli presented in a sequence of homogeneous repetitive, 'standard', stimuli. This negativity probably reflects an automatic neuronal-mismatch process with a neuronal representation of the standard stimulus. The present study aimed at determining the duration of the assumed neuronal representation by varying the inter-stimulus interval (ISI) of a stimulus block. It was assumed that a deviant stimulus can elicit a MMN only when the neuronal representation of the previous standard stimulus still exists. It was found that a clear MMN was elicited by the deviant stimulus when the ISI was 1 or 2 s, but not when the ISI was 4 or 8 s. This suggests that the duration of the neuronal representation involved was less than 4 s.