Neuroscience 2005 Abstract
| Presentation Number: | 985.19 |
|---|---|
| Abstract Title: | Activity in human area MT+ driven by spatially stable vibrotactile stimuli. |
| Authors: |
Moore, C. I.*1
; Nelson, A. J.1
; Cheney, C. A.1
; Crosier, E.1
; Dale, A.2
; Merzenich, M.1
; Savoy, R.2
; Greve, D.2
1McGovern Inst. Brain Res., MIT, Cambridge, MA 2MA, 77 Massachusetts Avenue, 02139, |
| Primary Theme and Topics |
Sensory and Motor Systems - Tactile/Somatosensory -- Thalamus and Cortex |
| Secondary Theme and Topics | Sensory and Motor Systems<br />- Multisensory |
| Session: |
985. Tactile/Somatosensory: Thalamus and Cortex V Poster |
| Presentation Time: | Wednesday, November 16, 2005 3:00 PM-4:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # EE20 |
| Keywords: | somatosensory, cortex, vision, motion |
Moving tactile stimuli have been reported to activate MT+ in humans (Hagen et al., 2002; Blake et al., 2004). While provocative, these studies did not examine the role of stimulus type, attention, task demand or generality to other primates. In studies in humans and squirrel monkeys (Nelson et al., SFN 2005; Aparicio & Moore, SFN 2005), we have begun to delineate the factors necessary for tactile activation of MT+.
In the present study, we examined the hypothesis that non-moving vibrotactile stimuli activate MT+. In an event-related design, human Ss (N = 7) received tactile stimulation (20 or 100 Hz) on the 3rd digit fingertip during 3T fMRI. Stimulus amplitude varied from 0-200um. Subjects performed tactile detection overtly (button press) or covertly, or performed no task during stimulation (‘passive’). Visually, subjects fixated a ‘+’ symbol, and appearance of a colored rectangle indicated covert or overt trials. No visual cue was present on passive trials. In 2 Ss, MT+ was functionally defined (oscillating vs. static rings).
In the vibrotactile study, we observed activation of MT+ in 6/7 Ss (p < .000001). In addition to activation evoked during task performance, stimulus-locked activation was observed when only vibrotactile input was presented. The magnitude of ‘passive’ tactile evoked signal changes (~.5%) matched analogous stimulation on covert and overt trials. In 2 Ss, tactile activity localized to an anterior and dorsal region of visually defined MT+.
These results show MT+ activity driven by non-moving tactile stimuli in a task where visual motion imagery was unlikely and no attentional demands existed. Vibrotactile stimuli in some ways parallel visual ‘flicker’, which also drives MT neurons. Taken with our results in anesthetized squirrel monkeys, these findings suggest a robust input to MT+, and imply a broader role for this region in information processing of temporally varying, spatially stable stimuli.
In the present study, we examined the hypothesis that non-moving vibrotactile stimuli activate MT+. In an event-related design, human Ss (N = 7) received tactile stimulation (20 or 100 Hz) on the 3rd digit fingertip during 3T fMRI. Stimulus amplitude varied from 0-200um. Subjects performed tactile detection overtly (button press) or covertly, or performed no task during stimulation (‘passive’). Visually, subjects fixated a ‘+’ symbol, and appearance of a colored rectangle indicated covert or overt trials. No visual cue was present on passive trials. In 2 Ss, MT+ was functionally defined (oscillating vs. static rings).
In the vibrotactile study, we observed activation of MT+ in 6/7 Ss (p < .000001). In addition to activation evoked during task performance, stimulus-locked activation was observed when only vibrotactile input was presented. The magnitude of ‘passive’ tactile evoked signal changes (~.5%) matched analogous stimulation on covert and overt trials. In 2 Ss, tactile activity localized to an anterior and dorsal region of visually defined MT+.
These results show MT+ activity driven by non-moving tactile stimuli in a task where visual motion imagery was unlikely and no attentional demands existed. Vibrotactile stimuli in some ways parallel visual ‘flicker’, which also drives MT neurons. Taken with our results in anesthetized squirrel monkeys, these findings suggest a robust input to MT+, and imply a broader role for this region in information processing of temporally varying, spatially stable stimuli.
Supported by McGovern Institute for Brain Research, MIT
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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