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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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Journal ArticleDOI
TL;DR: Both striate cortex and the superior colliculus contribute to the visual responses of STP neurons, which is crucial for the movement and stimulus specificity of neurons in STP.
Abstract: Although the tectofugal system projects to the primate cerebral cortex by way of the pulvinar, previous studies have failed to find any physiological evidence that the superior colliculus influences visual activity in the cortex. We studied the relative contributions of the tectofugal and geniculostriate systems to the visual properties of neurons in the superior temporal polysensory area (STP) by comparing the effects of unilateral removal of striate cortex, the superior colliculus, or of both structures. In the intact monkey, STP neurons have large, bilateral receptive fields. Complete unilateral removal of striate cortex did not eliminate visual responses of STP neurons in the contralateral visual hemifield; rather, nearly half the cells still responded to visual stimuli in the hemifield contralateral to the lesion. Thus the visual properties of STP neurons are not completely dependent on the geniculostriate system. Unilateral striate lesions did affect the response properties of STP neurons in three ways. Whereas most STP neurons in the intact monkey respond similarly to stimuli in the two visual hemifields, responses to stimuli in the hemifield contralateral to the striate lesion were usually weaker than responses in the ipsilateral hemifield. Whereas the responses of many STP neurons in the intact monkey were selective for the direction of stimulus motion or for stimulus form, responses in the hemifield contralateral to the striate lesion were not selective for either motion or form. Whereas the median receptive field in the intact monkey extended 80 degrees into the contralateral visual field, the receptive fields of cells with responses in the contralateral field that survived the striate lesions had a median border that extended only 50 degrees into the contralateral visual field. Removal of both striate cortex and the superior colliculus in the same hemisphere abolished the responses of STP neurons to visual stimuli in the hemifield contralateral to the combined lesion. Nearly 80% of the cells still responded to visual stimuli in the hemifield ipsilateral to the lesion. Unilateral removal of the superior colliculus alone had only small effects on visual responses in STP. Receptive-field size and visual response strength were slightly reduced in the hemifield contralateral to the collicular lesion. As in the intact monkey, selectivity for stimulus motion or form were similar in the two visual hemifields. We conclude that both striate cortex and the superior colliculus contribute to the visual responses of STP neurons. Striate cortex is crucial for the movement and stimulus specificity of neurons in STP.(ABSTRACT TRUNCATED AT 400 WORDS)

119 citations

Reference BookDOI
28 Jul 2003
TL;DR: This chapter discusses the development of Neuron Response Properties in Primary Visual Cortex, the Functional Organization of Monkey Inferotemporal Cortex, and Comparative Studies of Pyramidal Neurons in Visual Cortex of Monkeys.
Abstract: Introduction: A Brief Overview of the Primate Visual System. The K, P, and M Pathways from Retina to Cortex. The Pulvinar Complex. The Development of Neuron Response Properties in Primary Visual Cortex. The Second Visual Area, V2. The Superior Colliculus. Early Visual Areas: V2, V3, DM, DL, and MT. Plasticity of Visual Cortex in Adults. Processing Hierarchies in Visual Cortex. Visuomotor Areas in Frontal and Parietal Cortex. Specializations of Human Visual Cortex. Maps of the Visual Field in the Cerebral Cortex of Primates: Functional Organization and Significance. Face Expertise and Category Specialization in the Human Occipitotemporal Cortex. Motion Processing in Human Visual Cortex. The Functional Organization of Monkey Inferotemporal Cortex. Comparative Studies of Pyramidal Neurons in Visual Cortex of Monkeys. Feedback Connections: Splitting the Arrow.

117 citations

Journal ArticleDOI
TL;DR: The precision of the projection of the visual field to the dorsal lateral geniculate nucleus (LGNd) of the cat was studied by plotting the receptive fields of single neurons recorded extra-cellularly in the nucleus in terms of the random scatter of receptive field positions for cells recorded in a given electrode penetration.
Abstract: The precision of the projection of the visual field to the dorsal lateral geniculate nucleus (LGNd) of the cat was studied by plotting the receptive fields of single neurons recorded extra-cellularly in the nucleus. The concepts of a ‘projection column’ and of ‘random scatter in the location of receptive fields’ have been defined in relation to cells in the LGNd. A projection column contains 90% of all the cells in the LGNd that have receptive fields with a common visual direction, the central axis of the column being the projection line for the given visual direction. In the region of the LGNd devoted to central vision the columns have a circular cross section and are about 1 mm in diameter.

117 citations

Journal ArticleDOI
TL;DR: An analytical study of a neuronal network model of the local cortical circuit in primary visual cortex that obtains a trade-off between the spatial range of inhibition and its time constant and concludes that local connections are isotropic.
Abstract: Many models of cortical function assume that local lateral connections are specific with respect to the preferred features of the interacting cells and that they are organized in a Mexican-hat pattern with strong “center” excitation flanked by strong “surround” inhibition. However, anatomical data on primary visual cortex indicate that the local connections are isotropic and that inhibition has a shorter range than excitation. We address this issue in an analytical study of a neuronal network model of the local cortical circuit in primary visual cortex. In the model, the orientation columns specified by the convergent lateral geniculate nucleus inputs are arranged in a pinwheel architecture, whereas cortical connections are isotropic. We obtain a trade-off between the spatial range of inhibition and its time constant. If inhibition is fast, the network can operate in a Mexican-hat pattern with isotropic connections even with a spatially narrow inhibition. If inhibition is not fast, Mexican-hat operation requires a spatially broad inhibition. The Mexican-hat operation can generate a sharp orientation tuning, which is largely independent of the distance of the cell from the pinwheel center.

117 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231
20223
20212
20208
20192
20189