Poster C128, Sunday, March 26, 5:00 – 7:00 pm, Pacific Concourse
fMRI investigation of part-whole contingencies using 2-D shapes: A partial least squares analysis
Padmapriya Muralidharan1, Anthony Cate1; 1Virginia Polytechnic Institute and State University
Proposed frameworks of inferior temporal activity modulation by the basal ganglia in the occurrence of complex visual hallucinations (Middleton & Strick, 1996) as well as evidence for lateralized effects of the parietal-basal ganglia circuit in shape-related object recognition tasks (Schenden et al., 2009) indicate the presence of intricate neural networks crucial for higher-order visual perception. An fMRI investigation of connectivity of part-whole contingencies necessary for shape discrimination was conducted with healthy participants (N=17). The task involved presentation of 2D shapes composed of varying local contour features. Each of the three stimulus blocks consisted of unique parts forming distinct shapes. Presentations were made further distinctive with varying rates and order of repetitions. Hence, distinct block design conditions with different subsets of these shapes permitted a partial least squares analysis in the whole brain with a view to examine effects of part/object variation, repetition and distinctiveness. Patterns of connectivity in occiptotemporal networks consistent with previous literature about increased salience of local and global features emerged. Furthermore, connectivity with basal ganglia structures (caudate tail and substantia nigra) further corroborate the involvement of more anterior cortical and sub-cortical regions in part-whole interactions related to visual shape perception.
Topic Area: PERCEPTION & ACTION: Vision