The fronto-parietal network and top-down modulation of perceptual grouping.
We examined the role of the fronto-parietal cortex in top-down modulation of perceptual grouping by proximity, collinearity, and similarity, by recording event related brain potentials from two patients with fronto-parietal lesions and eight controls. We found that grouping by proximity and collinearity in the controls was indexed by short-latency activities over the medial occipital cortex and long-latency activities over the occipito-parietal areas. For the patients, however, both the short- and long-latency activities were eliminated or weakened. The results suggest that the fronto-parietal network is involved in facilitation of both the early and late grouping processes in the human brain.
Han
Shihui
S
Department of Psychology, Peking University, Beijing, P. R. China. shan@pku.edu.cn
Humphreys
Glyn W
GW
D000368:Aged; D001930:Brain Injuries / Q000473:pathology* / Q000503:physiopathology*; D001931:Brain Mapping; D004569:Electroencephalography / Q000379:methods; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology*; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology; D010296:Parietal Lobe / Q000473:pathology / Q000503:physiopathology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D013997:Time Factors