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Orientation column
About: Orientation column is a research topic. Over the lifetime, 1142 publications have been published within this topic receiving 130169 citations.
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TL;DR: Retinal projections and the degree of ocular segregation in the striate cortex were examined by transneuronal autoradiography following unilateral intraocular injections of 3H‐proline in a New World primate, the spider monkey.
Abstract: Retinal projections and the degree of ocular segregation in the striate cortex were examined by transneuronal autoradiography following unilateral intraocular injections of 3H-proline in a New World primate, the spider monkey (Ateles ater). The results show that, within the lateral geniculate nucleus (LGN), retinal fibers terminate in six principal layers and within the interlaminar spaces adjacent to the magnocellular layers, as well as the S layers ventral to the magnocellular layers. Projections to the superior colliculus, both ipsilateral and contralateral to the injected eye, were patchy and restricted to the superficial gray layer.
Our main result shows that, in the striate cortex, LGN projections terminate in well-defined ocular dominance columns in layer IV. Labelled columns were most clearly delimited in layer IVb, where they averaged 373 + 42μm in width in both the ipsilateral and contralateral hemipheres, slightly smaller than those reported originally from electrophysiological studies of striate cortex in spider monkeys (Hubel and Wiesel, '68). Unlabelled intercolumns were significantly narrower than labelled columns, which suggests that there may be overlap between input from the two eyes between columns. Quantitative measures showed above-background label also in cortical layers IIIb, V, and VI.
Our results support the idea that among primates, ocular dominance columns are not limited to Old World species. At the same time, it is apparent that spider monkeys are exceptional among New World primates in having sharply delimited columns. The functional significance of the variation in the degree of ocular segregation in the cortex and its relation to primate evolution are discussed.
41 citations
41 citations
TL;DR: A neural network model for explaining experimentally observed neuronal responses in cat primary visual cortex that satisfactorily account for experimental observations is proposed.
Abstract: A neural network model for explaining experimentally observed neuronal responses in cat primary visual cortex is proposed. In our model, the basic functional unit is an orientation column which is represented by a large homogeneous population of neurons modeled as integrate-and-fire type excitable elements. The orientation column exhibits spontaneous collective oscillations in activity in response to suitable visual stimuli. Such oscillations are caused by mutual synchronization among the neurons within the column. Numerical simulation for various stimulus patterns shows that as a result of activity correlations between different columns, the amplitude and the phase of the oscillation in each column depend strongly on the global feature of the stimulus pattern. These results satisfactorily account for experimental observations.
40 citations
TL;DR: This study supports the hypothesis that there exists a common pattern of visual cortical organization in rodents by showing that the arrangement of these labeled extrastriate areas resembles closely the physiologic and anatomic subdivision of the extrastiate cortex.
40 citations
TL;DR: The existing framework may be extended to a three-dimensional cortex and to more complex models of intracortical connectivity, and may be applied to other developmental phenomena including the development of lamination in the LGN, the formation of visual maps in experimentally altered auditory cortex, and the mapping of visual and auditory maps in the optic tectum.
40 citations