Decreased BOLD responses in audiovisual processing.
Audiovisual processing was studied in a functional magnetic resonance imaging study using the McGurk effect. Perceptual responses and the brain activity patterns were measured as a function of audiovisual delay. In several cortical and subcortical brain areas, BOLD responses correlated negatively with the perception of the McGurk effect. No brain areas with positively correlated BOLD responses were found. This was unexpected as most studies of audiovisual integration use additivity and super additivity - that is, increased BOLD responses after audiovisual stimulation compared with auditory-only and visual-only stimulation - as criteria for audiovisual integration. We argue that brain areas that show decreased BOLD responses that correlate with an integrated audiovisual percept should not be neglected from consideration as possibly involved in audiovisual integration.
Graduate School for Behavioural and Cognitive Neurosciences, University of Groningen, The Netherlands. j.e.c.wiersinga-post@med.umcg.nl
Esther
E
Wiersinga-Post
Sonja
S
Tomaskovic
Lavinia
L
Slabu
Remco
R
Renken
Femke
F
de Smit
Hendrikus
H
Duifhuis
D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D001288:Attention / Q000502:physiology; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D015536:Down-Regulation / Q000502:physiology; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000592:standards; D010775:Photic Stimulation / Q000379:methods; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult