Chromatic and Motion Processing

Early positron emitted tomographic (PET) studies of the functional organization of visual cortex in humans have concentrated on determining the location and specialization of the human homologs of macaque monkey areas V4 and MT. In a color-processing study aimed at identifying human homologs, regional cerebral blood flow (rCBF) measures were made while subjects viewed either chromatic or gray Mondrian patterns. Two statistically significant foci of activation were observed in the visual cortex: one in the occipital pole corresponding to V1-V2 and a second area in the lingual and fusiform gyrus corresponding to V4. In a motion-processing study aimed at identifying human MT, rCBF measures were made while subjects viewed either stationary or moving small black squares. Again two statistically significant foci were observed: one corresponding to V1-V2 and the second at the junction of the parietal and occipital cortices corresponding to area MT. Given the spatial resolution of the PET technique and the similarity of response properties in V1 and V2, these authors were unable to distinguish activation in V2 from that in V1. Nevertheless, this focus was active in each of the four stimulus conditions tested. Thus, V1-V2 were found to participate in both chromatic and gray scale analyses as well as in stationary and moving square analyses.

Breaking Bulimia

Breaking Bulimia

We have all been there: turning to the refrigerator if feeling lonely or bored or indulging in seconds or thirds if strained. But if you suffer from bulimia, the from time to time urge to overeat is more like an obsession.

Get My Free Ebook


Post a comment