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|Title:||Organization of the Clare-Bishop Area of Cat Visual Cortex (Extrastriate)|
|Department / Program:||Psychology|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||The primary visual pathway consists of projections from the retina to the lateral geniculate nucleus (LGN) and from the LGN to the visual cortex. The cat LGN has 3 major subdivisions containing independent representations of visual space: A layers, C layers, and the medial interlaminar nucleus (MIN). The visual cortex has more than 10 areas thought to process different aspects of vision. This thesis is about the functional organization of one of these cortical areas, the Clare-Bishop area, its geniculate afferent pathways, and its participation in associational cortical circuits. My basic findings are: (i) The MIN represents an area of the retina coincident with the reflective tapetum (Lee et al., 1984). Cells of the MIN have greater sensitivity in the dark than do the cells of other geniculate subdivisions. These findings suggest that the MIN is related to dim light vision. (ii) Associational input from area 18 is organized into a stripe-like pattern of inputs to the Clare-Bishop area that is under control of layer A. The influence of the MIN appears to be maximal in an interdigitating series of stripes, and there is some evidence of inhibitory interaction between the MIN- and layer A-dependent regions of the Clare-Bishop area. (iii) High acuity information is relayed through layer A to the Clare-Bishop area via simple cells of area 18. Some of these simple cells have receptive field properties suitable for 3-dimensional motion detection. (iv) Simple cells are largely under control of layer A, as in area 17 (Malpeli, 1983). Complex cells in both areas are in general independent of layer A.
Based on these results, I propose a theory of the Clare-Bishop area that involves parcellation and functional switching of cortical tissue for most efficient processing under both bright-light (high acuity) and dim-light (high sensitivity) conditions.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1986.
|Date Available in IDEALS:||2014-12-15|