Spatial remapping in the audio-tactile ventriloquism effect: a TMS investigation on the role of the ventral intraparietal area.
Previous studies have suggested that the putative human homologue of the ventral intraparietal area (hVIP) is crucially involved in the remapping of tactile information into external spatial coordinates and in the realignment of tactile and visual maps. It is unclear, however, whether hVIP is critical for the remapping process during audio-tactile cross-modal spatial interactions. The audio-tactile ventriloquism effect, where the perceived location of a sound is shifted toward the location of a synchronous but spatially disparate tactile stimulus, was used to probe spatial interactions in audio-tactile processing. Eighteen healthy volunteers were asked to report the perceived location of brief auditory stimuli presented from three different locations (left, center, and right). Auditory stimuli were presented either alone (unimodal stimuli) or concurrently to a spatially discrepant tactile stimulus applied to the left or right index finger (bimodal stimuli), with the hands adopting either an uncrossed or a crossed posture. Single pulses of TMS were delivered over the hVIP or a control site (primary somatosensory cortex, SI) 80 msec after trial onset. TMS to the hVIP, compared with the control SI-TMS, interfered with the remapping of touch into external space, suggesting that hVIP is crucially involved in transforming spatial reference frames across audition and touch.
Brain and Behavioral Sciences Department, University of Pavia, Piazza Botta 6, 27100 Pavia, Italy. chiara.renzi@unipv.it
Chiara
C
Renzi
Patrick
P
Bruns
Kirstin-Friederike
KF
Heise
Maximo
M
Zimerman
Jan-Frederik
JF
Feldheim
Friedhelm C
FC
Hummel
Brigitte
B
Röder
D000161:Acoustic Stimulation; D000328:Adult; D000704:Analysis of Variance; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology*; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D013017:Sound Localization / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D055698:Touch Perception / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult