|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||
1 McGill University
2 University of Montreal
* To whom correspondence should be addressed. E-mail: gary.duncan{at}umontreal.ca.
This event-related fMRI study examines the neural correlates of vibrotactile sensation within the context of different psychophysical demands. Nine subjects received vibrotactile stimuli on the right volar forearm during detection, localization and passive tasks. In the detection task, subjects indicated the offset (end) of each stimulus by pressing a response key with their left hand. In the localization task, subjects identified the location of the stimulus ('distal?' or 'proximal?') by pressing the appropriate response key 4s after the end of the stimulus. In the passive task, subjects received the same vibrotactile stimuli, but no response was required. Analysis of stimulus-evoked activity compared to the resting baseline period revealed significant bilateral secondary somatosensory cortex (SII) activation for all three tasks. However, only in the offset-detection and localization tasks was stimulus-evoked activation observed in other expected areas of tactile processing, such as contralateral primary somatosensory cortex neighboring the posterior parietal cortex (SI/PPC) and in bilateral anterior insular cortex (aIC). During the localization task, we identified vibrotactile-evoked activation in right aIC, which was maintained after the termination of the stimulus. Results suggest that vibrotactile-related activation within SI/PPC and aIC is enhanced by the increased levels of attention and cognitive demands required by the detection and localization tasks. Activation of aIC during vibrotactile stimulation, as well as during the post-stimulus delay in the localization trials, is consistent with the growing literature linking this area with the perception and short-term memory of tactile information.
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |