Mismatch negativity between discriminating and undiscriminating participants on the front-back sound localization

• Published in: Hearing research 2024-10, Vol.452, p.109094, Article 109094
• Main Authors: Hishikawa, Keito, Ogawa, Keiko
• Format: Article
• Language: English
• Subjects: Acoustic Stimulation; Adult; Brain - physiology; Deviance detection; Discrimination, Psychological; Electroencephalography; Event-related brain potentials; Evoked Potentials, Auditory; Female; Front-back sound localization; Humans; Male; Mismatch negativity (MMN); Perceptual ability; Reaction Time; Sound Localization - physiology; Time Factors; Young Adult
• ISSN: 0378-5955; 1878-5891; 1878-5891
• DOI: 10.1016/j.heares.2024.109094

•The study examined the deviance detection process in front-back sound localization in humans.•A comparison was made between a deviance-discriminating group and an undiscriminating group.•Both groups displayed similar results for the mismatch negativity (MMN) and P2 components.•However, differences were observed in MMN latency and N1 component results.•The brains of participants in the deviance-undiscriminating group may react differently to deviance detection in front and back directions. Sound localization in the front-back dimension is reported to be challenging, with individual differences. We investigated whether auditory discrimination processing in the brain differs based on front-back sound localization ability. This study conducted an auditory oddball task using speakers in front of and behind the participants. We used event-related brain potentials to examine the deviance detection process between groups that could and could not discriminate front-back sound localization. The results indicated that mismatch negativity (MMN) occurred during the deviance detection process, and P2 amplitude differed between standard and deviant locations in both groups. However, the latency of MMN was shorter in the group that could discriminate front-back sounds than in the group that could not. Additionally, N1 amplitude increased for deviant locations compared to standard ones only in the discriminating group. In conclusion, the sensory memories matching process based on traces of previously presented stimuli (MMN, P2) occurred regardless of discrimination ability. However, the response to changes in the physical properties of sounds (MMN latency, N1 amplitude) differed depending on the ability to discriminate front-back sounds. Our findings suggest that the brain may have different processing strategies for the two directions even without subjective recognition of the front-back direction of incoming sounds.