The goal of the proposed experiments is to investigate the structural and functional organization of interhemispheric connections of visual areas 17, 18 and 19 in cat cerebral cortex. To achieve this goal, the morphology and synaptology of cells which project axons through the corpus callosum will be determined to ascertain if any of the neurons are non-pyramidal cells which are inhibitory in function. In addition, we will examine the types of synapses which local and long-distance axon collaterals of callosally projecting pyramidal cells form and the nature of their postsynaptic targets. This part of the study will reveal the morphological bases by which callosally projecting neurons in one hemisphere can influence the functions of nearby neurons in the same hemisphere and distant neurons in the contralateral hemisphere. The region of visual space represented in the callosal cell zone and callosal terminal zone of each area will be determined by compiling topographic maps and comparing these maps to the location of the callosal zones defined in the same animal. This part of the study will provide us with insights into the relative contributions played by different cortical areas in one hemisphere in the processing of visual information in the opposite hemisphere. Such insights are important if we are to understand the mechanisms which allow the two hemispheres to operate as an integrated whole.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY006404-02
Application #
3262430
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1986-04-01
Project End
1990-03-31
Budget Start
1987-04-01
Budget End
1988-03-31
Support Year
2
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Boston University
Department
Type
Schools of Medicine
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02118
Hughes, C M; Peters, A (1992) Symmetric synapses formed by callosal afferents in rat visual cortex. Brain Res 583:271-8
Hughes, C M; Peters, A (1992) Types of callosally projecting nonpyramidal neurons in rat visual cortex identified by lysosomal HRP retrograde labeling. Anat Embryol (Berl) 186:183-93
Payne, B R; Siwek, D F (1991) The visual map in the corpus callosum of the cat. Cereb Cortex 1:173-88
Payne, B R; Siwek, D F (1991) Visual-field map in the callosal recipient zone at the border between areas 17 and 18 in the cat. Vis Neurosci 7:221-36
Payne, B R; Siwek, D F; Lomber, S G (1991) Complex transcallosal interactions in visual cortex. Vis Neurosci 6:283-9
Payne, B R (1991) Visual-field map in the transcallosal sending zone of area 17 in the cat. Vis Neurosci 7:201-19
Peters, A; Payne, B R; Josephson, K (1990) Transcallosal non-pyramidal cell projections from visual cortex in the cat. J Comp Neurol 302:124-42
Payne, B R (1990) Representation of the ipsilateral visual field in the transition zone between areas 17 and 18 of the cat's cerebral cortex. Vis Neurosci 4:445-74
Hughes, C M; Peters, A (1990) Morphological evidence for callosally projecting nonpyramidal neurons in rat visual cortex. Anat Embryol (Berl) 182:591-603
Payne, B R (1990) Function of the corpus callosum in the representation of the visual field in cat visual cortex. Vis Neurosci 5:205-11

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