fMRI Evidence for Generalised Arousal as a Substitute for Early Selection in Autism during Conditions of Shifting Visual Spatial Attention

The purpose of our first analysis, task versus fixation, was to map within each individual subject the regions that were activated during the task. This analysis was performed using a permutation test that we've implemented and released as part of the AFNI software package.

Here in a typical subject you can see task activations in inferior- lateral occipitotemporal cortex, intraparietal sulcus, and superior parietal lobe, and the regions of interest drawn to match those activations. Note that although these regions are being constructed on the basis of Analysis #1, they are being drawn a priori to Analysis #2.

Although drawing regions within individuals is more labour-intensive than computing everything on a Talairach-transformed average brain, given the very small attentional effect sizes that we're looking at, and also the individual variability of the anatomy (especially in the case of intraparietal sulcus), this technique is essential.

`fMRI Evidence for Generalised Arousal as a Substitute for Early Selection in Autism during Conditions of Shifting Visual Spatial Attention', Matthew Belmonte, 10 November 2001