Topic
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: The findings support the conclusion that radial bias is not necessary for orientation decoding, and highlight potential limitations of using temporal phase-encoded fMRI designs for characterizing voxel tuning properties.
39 citations
TL;DR: Recordings have been made from 213 striate cortex units in esotropic and orthophoric adult Siamese cats, and no units were found to have receptive fields in both eyes, and none were found which had receptive field in the ipsilateral eye.
39 citations
TL;DR: Data indicates that fast movements of single whiskers in varying directions correlate with different patterns of activation in the somatosensory cortex, which supports prior research that vibrissae deflections cause responses in different cortical neurons within the barrel field according to the direction of the deflection.
39 citations
TL;DR: It is demonstrated that the specific modulation pattern of layer-4 activity, which emerges from inter-laminar synaptic connections, is crucial for a rapid shift of attention to a currently unattended stimulus, and the results suggest that top-down signals act differently on different layers of the cortical microcircuit.
Abstract: A vast amount of information about the external world continuously flows into the brain, whereas its capacity to process such information is limited. Attention enables the brain to allocate its resources of information processing to selected sensory inputs for reducing its computational load, and effects of attention have been extensively studied in visual information processing. However, how the microcircuit of the visual cortex processes attentional information from higher areas remains largely unknown. Here, we explore the complex interactions between visual inputs and an attentional signal in a computational model of the visual cortical microcircuit. Our model not only successfully accounts for previous experimental observations of attentional effects on visual neuronal responses, but also predicts contrasting differences in the attentional effects of top-down signals between cortical layers: attention to a preferred stimulus of a column enhances neuronal responses of layers 2/3 and 5, the output stations of cortical microcircuits, whereas attention suppresses neuronal responses of layer 4, the input station of cortical microcircuits. We demonstrate that the specific modulation pattern of layer-4 activity, which emerges from inter-laminar synaptic connections, is crucial for a rapid shift of attention to a currently unattended stimulus. Our results suggest that top-down signals act differently on different layers of the cortical microcircuit.
38 citations
TL;DR: This study examines the arrangement of orientation pinwheel centers in the cat visual cortex by optical imaging of intrinsic signals and suggests that the areal border imposes a strong restriction on the pattern formation of orientation preference maps in the visual cortex.
Abstract: In the primary visual cortex of higher mammals, orientation preferences are represented continuously except for singular points, so-called pinwheel centers. In spite of the uniqueness of orientation pinwheel centers, very little is known about the pattern of their arrangement. In this study we examined the arrangement of orientation pinwheel centers in the cat visual cortex by optical imaging of intrinsic signals. Our results demonstrate that orientation pinwheel centers are arranged in a unique geometric pattern around the area 17/18 transition zone: pinwheel centers of the same type are arranged in rows parallel to the transition zone, and rows of clockwise and counterclockwise pinwheel centers are arranged alternately. We suggest that the areal border imposes a strong restriction on the pattern formation of orientation preference maps in the visual cortex.
38 citations