Mismatch negativity evoked by the McGurk-MacDonald effect: a phonetic representation within short-term memory.
OBJECTIVE
The McGurk-MacDonald illusory percept is obtained by dubbing an incongruent articulatory movement on an auditory phoneme. This type of audiovisual speech perception contributes to the assessment of theories of speech perception. The mismatch negativity (MMN) reflects the detection of a deviant stimulus within the auditory short-term memory and besides an acoustic component, possesses, under certain conditions, a phonetic one. The present study assessed the existence of an MMN evoked by McGurk-MacDonald percepts elicited by audiovisual stimuli with constant auditory components.


METHODS
Cortical evoked potentials were recorded using the oddball paradigm on 8 adults in 3 experimental conditions: auditory alone, visual alone and audiovisual stimulation. Obtaining illusory percepts was confirmed in an additional psychophysical condition.


RESULTS
The auditory deviant syllables and the audiovisual incongruent syllables elicited a significant MMN at Fz. In the visual condition, no negativity was observed either at Fz, or at O(z).


CONCLUSIONS
An MMN can be evoked by visual articulatory deviants, provided they are presented in a suitable auditory context leading to a phonetically significant interaction. The recording of an MMN elicited by illusory McGurk percepts suggests that audiovisual integration mechanisms in speech take place rather early during the perceptual processes.
Colin
C
C
Research Unit in Cognitive Neurosciences, Université Libre de Bruxelles, CP 191, Av. F.D. Roosevelt, 50, B-1050, Brussels, Belgium. ccolin@ulb.ac.be
Radeau
M
M
Soquet
A
A
Demolin
D
D
Colin
F
F
Deltenre
P
P
D000161:Acoustic Stimulation / Q000379:methods / Q000706:statistics & numerical data*; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D010700:Phonetics; D010775:Photic Stimulation / Q000379:methods; D013067:Speech Perception / Q000502:physiology