2 s, followed by a cross-hair for 3 s. Ten such trials were presented in each block and a single run consisted of two blocks each of the Motion and Static stimuli. Pediatric participants underwent a training session in a mock scanner prior to the experiment to familiarize them with the MRI environment and all subjects practiced the tasks prior to the scan. Data were acquired using a 3T Siemens Trio scanner located in the Center for Functional and Molecular Imaging at the Georgetown University Medical Center,

Washington, DC. For each run, 89 functional images consisting find more of 50 contiguous whole-brain axial slices were acquired using an echo-planar imaging (EPI) sequence and the following parameters: TR = 3 s, TE = 30 ms, flip angle = 90°, FOV = 192 mm, slice thickness = 2.8 mm (0.2 mm interslice gap), in-plane resolution = 64 × 64, and voxel size = 3 mm isotropic. SPM8 was

used in analysis of functional MRI data sets. The first five scans of each run were discarded to account for T1 saturation effects. Resulting data sets were realigned to the mean of the remaining images, normalized to the Montreal Neurological Institute EPI template, resampled to an isotropic voxel size of 2 mm3, and smoothed with a Gaussian kernel of 8 mm full-width at half-maximum. Statistical analysis was performed based on the general linear model. Functional data sets were high-pass filtered with a cut-off of 128 s to account for signal drift and corrected AZD8055 for autocorrelations using an AR(1)

model. Stimulus onsets were modeled using the SPM canonical hemodynamic response function, and within-subject parametric maps were created for the motion-specific contrast (Motion > Static). Area V5/MT was functionally identified via its responsivity to the visual motion stimulus. In Experiment 1, V5/MT was identified individually in each subject via the contrast of Motion versus Static. For this single-subject analysis, Casein kinase 1 we searched for clusters within Talairach coordinates bounded by previously defined anatomical volumes: x = lateral to ±35; y = posterior to −60; z = −9 to +13 (Dumoulin et al., 2000; Tootell et al., 1995; Watson et al., 1993). To avoid circularity, we performed this identification of V5/MT using half the data acquired, while the other half was utilized in percent signal change calculation. Allocation of task blocks for this split between the two halves of the run was randomized across subjects. Data from Experiment 1 were also used to determine the ROI used in Experiments 2 and 3, however, this time using a different analysis, since Experiment 1 involved a different group of subjects than those participating in Experiments 2 and 3. An independent ROI was identified via a second level random-effects whole-brain analysis (no anatomical boundaries or masks were used here) performed using a one-sample t test to combine activation for the motion specific contrast over all the subjects in Experiment 1.