Enhanced visuo-haptic integration for the non-dominant hand.
Visuo-haptic integration contributes essentially to object shape recognition. Although there has been a considerable advance in elucidating the neural underpinnings of multisensory perception, it is still unclear whether seeing an object and exploring it with the dominant hand elicits the same brain response as compared to the non-dominant hand. Using fMRI to measure brain activation in right-handed participants, we found that for both left- and right-hand stimulation the left lateral occipital complex (LOC) and anterior cerebellum (aCER) were involved in visuo-haptic integration of familiar objects. These two brain regions were then further investigated in another study, where unfamiliar, novel objects were presented to a different group of right-handers. Here the left LOC and aCER were more strongly activated by bimodal than unimodal stimuli only when the left but not the right hand was used. A direct comparison indicated that the multisensory gain of the fMRI activation was significantly higher for the left than the right hand. These findings are in line with the principle of "inverse effectiveness", implying that processing of bimodally presented stimuli is particularly enhanced when the unimodal stimuli are weak. This applies also when right-handed subjects see and simultaneously touch unfamiliar objects with their non-dominant left hand. Thus, the fMRI signal in the left LOC and aCER induced by visuo-haptic stimulation is dependent on which hand was employed for haptic exploration.
Institute of Medical Psychology, Goethe-University, Heinrich-Hoffmann-Strasse 10, D-60528 Frankfurt am Main, Germany. Electronic address: Yalachkov@med.uni-frankfurt.de.
Yavor
Y
Yalachkov
Institute of Medical Psychology, Goethe-University, Heinrich-Hoffmann-Strasse 10, D-60528 Frankfurt am Main, Germany.
Jochen
J
Kaiser
Institute of Medical Psychology, Goethe-University, Heinrich-Hoffmann-Strasse 10, D-60528 Frankfurt am Main, Germany.
Oliver
O
Doehrmann
Institute of Medical Psychology, Goethe-University, Heinrich-Hoffmann-Strasse 10, D-60528 Frankfurt am Main, Germany.
Marcus J
MJ
Naumer
D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D002531:Cerebellum / Q000098:blood supply / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006225:Hand / Q000294:innervation*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009778:Occipital Lobe / Q000098:blood supply / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010812:Physical Stimulation; D014110:Touch / Q000502:physiology; D055698:Touch Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
D010100:Oxygen
Anterior cerebellum; Functional magnetic resonance imaging; Inverse effectiveness; Lateral occipital complex; Multisensory integration; Non-dominant hand; Object familiarity; Visuo-haptic; Visuo-tactile; fMRI