MMN, short for mismatch negativity, is a neural response measured by electroencephalography (EEG) or magnetoencephalography (MEG) that occurs in the human brain when it detects a sudden and unexpected change in an auditory, visual, or tactile stimulus. It refers to the negative deflection seen in the event-related potential (ERP) waveform that emerges approximately 100 to 250 milliseconds after the occurrence of a deviant stimulus in a sequence of repeated standard stimuli.
This event-related potential is generated as a result of automatic and pre-attentive processing, meaning that it occurs automatically without conscious effort or attention from the individual. MMN is often used as an index for a variety of cognitive processes, primarily involving the mechanisms of auditory perception, sensory memory, and automatic change detection.
MMN is characterized by its robustness and sensitivity to subtle changes in stimuli, making it a fundamental and widely-studied component of cognitive neuroscience. It has been extensively examined in a range of contexts, including language processing, auditory perception disorders, schizophrenia, autism spectrum disorder, and neurodevelopmental disorders.
Overall, MMN provides a valuable tool for assessing the brain's ability to detect changes in environmental stimuli, acting as a response indicating a mismatch between expected and actual sensory information. Its examination contributes to the understanding of various cognitive processes and has practical applications in clinical and research settings for investigating attention, perception, and brain disorders.
