Presentation rate and magnitude of stimulus deviance effects on human pre-attentive change detection.

The present study investigated the effects of the inter-stimulus interval (ISI) and the magnitude of deviance on the mismatch negativity (MMN), an event-related potential index of pre-attentive change detection. The latency of the MMN to infrequent changes in intensity and duration was prolonged by increasing the ISI from 400 ms to 4 s. Results indicate that these features are preserved in sensory memory for several seconds. By increasing the ISI the sharpness of the neural traces decreases, thus prolonging the change detection process.