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Visualstimuluspresentcition
The visual stimuli were back-projected from a liquid crystal display projector
(Sony Electronics, San Diego, CA) onto a Lucite screen (Da-Lite, Warsaw, IN) and viewed
through a mirror attached to the MR head coil. The visual stimuli for the MT∕MST
Iocalizer consisted of low-contrast random dots presented in the left or right hemifields
(Huk, et al. 2002). The dots moved radially in or out on sequential trials with slightly
varying speeds (randomly chosen from 3-5o∕s) to minimize adaptation. The visual
stimuli for the LOC Iocalizer consisted of photographs and scrambled photographs from
a variety of object categories.
fMRI experimental design
The visual area Iocalizer experiments were conducted using a block design. There
were eight 30 s blocks in each 4 min scan series, with each block containing 20 s of
stimulation (10 trials) of a single stimulation type followed by 10 s of baseline.
Regressors were created by convolving the timing of each type of stimulation block with
a gamma-variate function to account for the BOLD hemodynamic response function.
The Vibrotactile experiments were conducted using a rapid event-related design.
There were 110 2 s stimulation trials in each 5 min scan series: 25 for each of left and
right hand and foot and 10 catch (hip) trials (see below, Behavioral Task). Interspersed
between stimulation trials were intervals of fixation (80 s total). An optimal stimulus
sequence generator (optseq2) (Dale 1999) generated a pseudorandom ordering for the
different trial types and fixation, resulting in a range of interstimulus intervals from 0 to