title: Feedback from visual cortical area 7 to areas 17 and 18 in cats: How neural web is woven during feedback.
abstract: To investigate the feedback effect from area 7 to areas 17 and 18, intrinsic signal optical imaging combined with pharmacological, morphological methods and functional magnetic resonance imaging (fMRI) was employed. A spatial frequency-dependent decrease in response amplitude of orientation maps was observed in areas 17 and 18 when area 7 was inactivated by a local injection of GABA, or by a lesion induced by liquid nitrogen freezing. The pattern of orientation maps of areas 17 and 18 after the inactivation of area 7, if they were not totally blurred, paralleled the normal one. In morphological experiments, after one point at the shallow layers within the center of the cat's orientation column of area 17 was injected electrophoretically with HRP (horseradish peroxidase), three sequential patches in layers 1, 2 and 3 of area 7 were observed. Employing fMRI it was found that area 7 feedbacks mainly to areas 17 and 18 on ipsilateral hemisphere. Therefore, our conclusions are: (1) feedback from area 7 to areas 17 and 18 is spatial frequency modulated; (2) feedback from area 7 to areas 17 and 18 occurs mainly ipsilaterally; (3) histological feedback pattern from area 7 to area 17 is weblike.
authors.affiliation: Life Science School, Fudan University, Shanghai 200433, China; Center of Magnetic Resonance Research, University of Minnesota, Minneapolis, MN 55455, USA. Electronic address: 021023050@fudan.edu.cn.
authors.forename: X
authors.initials: X
authors.lastname: Yang
authors.affiliation: Huaiyin Normal University, Huaian 223300, China.
authors.forename: H
authors.initials: H
authors.lastname: Ding
authors.affiliation: The Advanced Institute of Translational Medicine and School of Software Engineering, Tongji University, Shanghai 200073, China. Electronic address: jwlu33@tongji.edu.cn.
authors.forename: J
authors.initials: J
authors.lastname: Lu
mesh_terms: D000818:Animals; D002415:Cats; D003452:Cryosurgery; D056228:Feedback, Sensory / Q000187:drug effects / Q000502:physiology*; D006735:Horseradish Peroxidase / Q000008:administration & dosage / Q000494:pharmacology; D008279:Magnetic Resonance Imaging; D009415:Nerve Net / Q000187:drug effects / Q000293:injuries / Q000502:physiology*; D061848:Optical Imaging; D014793:Visual Cortex / Q000187:drug effects / Q000293:injuries / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D005680:gamma-Aminobutyric Acid; D006735:Horseradish Peroxidase
keywords: area 7; cat; feedback; horseradish peroxidase; patch; γ-amino-butyric acid