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Mismatch negativity in dichotic listening: evidence for interhemispheric differences and multiple generators
L Y Deouell1, S Bentin, M H Giard
1Department of Psychology, Hebrew University of Jerusalem, Israel. msleon@mscc.huji.ac.il
Psychophysiology
|June 27, 1998
Summary
Mismatch negativity (MMN) brain responses to auditory deviants were similar whether stimuli were delivered via earphones or loudspeakers. Hemispheric differences in MMN amplitude and scalp current density were observed depending on the deviant stimulus side.
Area of Science:
- Neuroscience
- Auditory Perception
- Cognitive Neuroscience
Background:
- Mismatch negativity (MMN) is an event-related potential reflecting automatic auditory change detection.
- Dichotic stimulation allows for the investigation of hemispheric processing of auditory stimuli.
- Understanding MMN generators is crucial for elucidating auditory deviance detection mechanisms.
Purpose of the Study:
- To investigate the characteristics of mismatch negativity (MMN) elicited by dichotic stimulation.
- To compare MMN responses to frequency-deviant stimuli presented to the left, right, or both ears.
- To examine MMN generation using both earphones and free-field loudspeaker stimulation.
Main Methods:
- Participants listened to frequency-deviant auditory stimuli presented dichotically via earphones and loudspeakers.
- Mismatch negativity (MMN) was recorded using electroencephalography (EEG).
- Scalp current density analysis was performed to investigate MMN generator locations.
Main Results:
- Comparable MMNs were elicited regardless of stimulus side (left, right, both) or delivery mode (earphones, loudspeakers).
- A larger MMN amplitude was observed in the right hemisphere compared to the left hemisphere with earphone stimulation.
- Scalp current density analysis indicated distinct hemispheric patterns for left- versus right-sided deviance.
Conclusions:
- The findings support a multiple-generator model for mismatch negativity (MMN).
- Auditory deviance detection involves complex, asymmetric hemispheric processing.
- The results suggest shared attention mechanisms between auditory and visual modalities.