Intrinsic Connectivity in Area 18 of the Cat
Part of the
NATO Advanced Study Institutes Series
book series (NSSA, volume 27)
In order to determine the organization of afferent and intrinsic connectivity in area 18 of the cat, latencies and scatter of single-unit responses to electrical stimulation of the primary afferents were analyzed. The units’ laminar positions were assessed by evaluating current source densities along the same recording track on the way back to the cortical surface.
Mono-, di-, and trisynaptic responses are discernible in the latency histogram after stimulation of the lateral geniculate nucleus. The monosynaptic responses can be subdivided into two classes according to their latency scatter. The low scatter of the disynaptic responses suggests that they arise almost exclusively from the low scatter monosynaptic activity.
The most prominent feature of layers I–III is the preponderance of disynaptic responses which are followed by trisynaptic activity in about 30% of the cells. The most striking properties of the infragranular layers are the high percentage of multispike responses and the large scatter of latencies between cells.
The wiring diagram that accounts for the temporal and spatial properties of the analyzed responses shows strong and local connections from the input stage cells in layer IV to cells in the supragranular layers and in layer V. In addition, the supragranular and, probably also, the infragranular layers project onto themselves forming positive feedback loops.
KeywordsLateral Geniculate Nucleus Current Source Density Cell Somata Intrinsic Connectivity Supragranular Layer
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
Cleland, B. G., M. W. Dubin, and W. R. Levick (1971). Sustained and transient neurones in the cat’s retina and lateral geniculate nucleus. J. Physiol., Lond. 217:473–496.PubMedGoogle Scholar
Hoffmann, K.-P., J. Stone, and S. M. Sherman (1972). Relay of receptive-field properties in dorsal lateral geniculate nucleus of the cat. J. Neurophysiol. 35:518–531.PubMedGoogle Scholar
LeVay, S., and C. D. Gilbert (1976). Laminar patterns of geniculo-cortical projection in the cat. Brain Res. 113: 1–19.PubMedCrossRefGoogle Scholar
Lund, J. S., and R. G. Boothe (1975). Interlaminar connections and pyramidal neuron organisation in the visual cortex, area 17, of the macaque monkey. J. Comp. Neurol. 159:305–334.CrossRefGoogle Scholar
Mitzdorf, U., and W. Singer (1978). Prominent excitatory pathways in the cat visual cortex (A17 and A18): a current source density analysis of electrically evoked potentials. Exp. Brain Res. 33:371–394.PubMedCrossRefGoogle Scholar
Nauta, H. J. W., A. B. Butler, and J. A. Jane (1973). Some observations on axonal degeneration resulting from superficial lesions of the cerebral cortex. J. Comp. Neurol. 150:349–360.PubMedCrossRefGoogle Scholar
Singer, W., and N. Bedworth (1973). Inhibitory interaction between X and Y units in the cat lateral geniculate nucleus. Brain Res. 49:291–307.PubMedCrossRefGoogle Scholar
Singer, W., F. Tretter, and M. Cynader (1975). Organization of cat striate cortex: a correlation of receptive-field properties with afferent and efferent connections. J. Neurophysiol. 38:1080–1098.PubMedGoogle Scholar
Stone, J., and B. Dreher (1973). Projection of X-and Y-cells of the cat’s lateral geniculate nucleus to areas 17 and 18 of visual cortex. J. Neurophysiol. 36:551–567.PubMedGoogle Scholar
Tretter, F., M. Cynader, and W. Singer (1975). Cat parastriate cortex: a primary or secondary visual area? J. Neurophysiol. 38:1099–1113.Google Scholar
Van Essen, D., and J. Kelly (1973). Correlation of cell shape and function in the visual cortex of the cat. Nature 241:403–405.PubMedCrossRefGoogle Scholar
© Plenum Press, New York 1979