The lateralization and reliability of spatial mismatch negativity elicited by auditory deviants with virtual spatial location.

Mismatch negativity (MMN) is an intensively studied event-related potential component that reflects pre-attentive auditory processing. Existing spatial MMN (sMMN) studies usually use loud-speakers in different locations or deliver sound with binaural localization cues through earphones to elicit MMN, which either was practically complicated or sounded unnatural to the subjects. In the present study, we generated head related transfer function (HRTF)-based spatial sounds and verified that the HRTF-based sounds retained the left and the right spatial localization cues. We further used them as deviants to elicit sMMN with conventional oddball paradigm. Results showed that sMMN was successfully elicited by the HRTF-based deviants in 18 of 21 healthy subjects in two separate sessions. Furthermore, the left deviants elicited higher sMMN amplitudes in the right hemisphere compared to the left hemisphere, while the right deviants elicited sMMN with similar amplitudes in both hemispheres, which supports a combination of contralateral and right-hemispheric dominance in spatial auditory information processing. In addition, the sMMN in response to the right deviants showed good test-retest reliability, while the sMMN in response to the left deviants had weak test-retest reliability. These findings implicate that HRTF-based sMMN could be a robust paradigm to investigate spatial localization and discrimination abilities.