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To gain a deeper understanding of the transmission of visual signals from retina through the lateral geniculate nucleus (LGN), we have used a simple leaky integrate and-fire model to simulate a relay cell in the LGN. The simplicity of the model was motivated by two questions: (1) Can an LGN model that is driven by a retinal spike train recorded as synaptic(More)
Neurons responding selectively to different colours have been found in various cortical areas in macaque monkeys; however, little is known about whether and how the representation of colour is spatially organized in any cortical area. Cortical area V2 contains modules that respond preferentially to chromatic modulation, which are located in thin cytochrome(More)
The macaque striate cortex (V1) contains neurons that respond preferentially to various hues. The properties of these hue-selective neurons have been studied extensively at the single-unit level, but it is unclear how stimulus hue is represented by the distribution of activity across neuronal populations in V1. Here we use the intrinsic optical signal to(More)
The organization of projections from V2 thin stripes and interstripes to V4 was investigated using a combination of physiological and anatomical techniques. The compartments of V2 were first characterized, in vivo, using optical recording of intrinsic signals. Multiple anterograde tracers were then injected into different V2 compartments. The distribution(More)
The early visual cortices represent information of several stimulus attributes, such as orientation and color. To understand the coding mechanisms of these attributes in the brain, and the functional organization of the early visual cortices, it is necessary to determine whether different attributes are represented by different compartments within each(More)
It has been controversial whether the cytochrome oxidase (CO)-dense blobs in primate primary visual cortex (V1) and CO-dense thin stripes in visual area 2 (V2) are parts of a cortical color-processing stream that is segregated from other functional streams. One of the key pieces of evidence for the segregated color stream is the previous report of specific(More)
Relay neurons in the lateral geniculate nucleus (LGN) receive direct visual input predominantly from a single retinal ganglion cell (RGC), in addition to indirect input from other sources including interneurons, thalamic reticular nucleus (TRN), and the visual cortex. To address the extent of influence of these indirect sources on the response properties of(More)
We investigate the spatial correlations of orientation and color information in natural images. We find that the correlation of orientation information falls off rapidly with increasing distance, while color information is more highly correlated over longer distances. We show that orientation and color information are statistically independent in natural(More)
Information about various visual attributes orientation and color is represented in the primate striate cortex (V1) before reaching extrastriate cortices. An important question regarding the functional architecture of V1 is whether these dierent attributes are represented by separate populations of neurons. However, previous studies using single-or(More)
Many studies have provided evidence for the existence of universal constraints on color categorization or naming in various languages, but the biological basis of these constraints is unknown. A recent study of the pattern of color categorization across numerous languages has suggested that these patterns tend to avoid straddling a region in color space at(More)