PET reveals occipitotemporal pathway activation during elementary form perception in humans

• Published in: Visual neuroscience 1998-05, Vol.15 (3), p.503-510
• Main Authors: BEASON-HELD, LORI L., PURPURA, KEITH P., VAN METER, JOHN W., AZARI, NINA P., MANGOT, DAVID J., OPTICAN, LANCE M., MENTIS, MARC J., ALEXANDER, GENE E., GRADY, CHERYL L., HORWITZ, BARRY, RAPOPORT, STANLEY I., SCHAPIRO, MARK B.
• Format: Article
• Language: English
• Subjects: Adult; Anatomical correlates of behavior; Behavioral psychophysiology; Biological and medical sciences; Blood Flow Velocity; Brain - blood supply; Cerebrovascular Circulation; Extrastriate; Female; Form Perception - physiology; Frontal lobe; Fundamental and applied biological sciences. Psychology; Hippocampus; Humans; Male; Occipital Lobe - diagnostic imaging; Occipital Lobe - physiology; Positron emission tomography; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Striate; Temporal Lobe - diagnostic imaging; Temporal Lobe - physiology; Tomography, Emission-Computed; Visual; Visual Pathways - diagnostic imaging; Visual Pathways - physiology
• ISSN: 0952-5238; 1469-8714
• DOI: 10.1017/S0952523898153117

To define brain regions involved in feature extraction or elementary form perception, regional cerebral blood flow (rCBF) was measured using positron emission tomography (PET) in subjects viewing two classes of achromatic textures. Textures composed of local features (e.g. extended contours and rectangular blocks) produced activation or increased rCBF along the occipitotemporal pathway relative to textures with the same mean luminance, contrast, and spatial-frequency content but lacking organized form elements or local features. Significant activation was observed in striate, extrastriate, lingual, and fusiform cortices as well as the hippocampus and brain stem. On a scan-by-scan basis, increases in rCBF shifted from the occipitotemporal visual cortices to medial temporal (hippocampus) and frontal lobes with increased exposure to only those textures containing local features. These results suggest that local feature extraction occurs throughout the occipitotemporal (ventral) pathway during extended exposure to visually salient stimuli, and may indicate the presence of similar receptive-field mechanisms in both occipital and temporal visual areas of the human brain.