The name is absent

19

1988) (Lewis and Van Essen 2000a). Therefore, we used anatomical and functional
criteria to fractionate MT+ into MT and MST to separately measure tactile responses in
each area. Because tactile responses have also been reported in the lateral occipital
complex (LOC) (Amedi, et al. 2002; Amedi, et al. 2001), a region that overlaps MT+
(Kourtzi, et al. 2002), we also mapped the LOC in each subject to allow independent
measurements of activity in MT, MST, and LOC.

Weadoptedtwostrategiestotestwhethersomatosensoryresponses
independent of visual imagery exist in MT+. First, we used Vibrotactile stimuli delivered
by piezoelectric bending elements to widely separated sites on the body surface.
Because these stimuli do not contain any motion (real or apparent) relative to the body
surface, although they do move perpendicular to the skin surface (a necessary
precondition for activating mechanoreceptors), they are unlikely to induce the visual
imagery of motion known to activate MT+. Second, we delivered Vibrotactile stimulation
to the ipsilateral and contralateral hands and feet of the subjects. If tactile activation in
MT+ is produced by visual imagery of the tactile stimulus, the site of somatosensory
stimulation should have relatively little effect. For instance, touching a rotating globe
with the left hand or the right hand should induce similar amounts of visual motion
imagery and concomitant activation in MT+. In contrast, one of the organizing principles
of the somatosensory system is somatotppy, a map of the body surface. If MT+ tactile
responses are not produced by imagery of visual motion, MT+ should show modulation
by the body site of stimulation.

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