The specific aims of this proposal are designed to test the ideas of recurrent models of primary visual cortex V1, to understand the mechanisms of V1's role in vision.
Aim 1 is about the importance of inhibition for orientation tuning in V1, based on the dynamics of responses compare to model predictions.
Aim 2 examines the response of V1 neurons to contrast reversal as a function of orientation.
Aim 3 is about the contrast dependence of Untuned Suppression and how it relates to the invariance or non- invariance of orientation tuning with contrast.
Aim 4 is about spatial phase specificity and the specificity of local connections in the cortical network. The rationale is that a crucial differentiating feature between different models is how phase-specific are the interactions between neurons in the network. We will measure the spatial phase specificity of neurons in the local network, in different V1 layers, using a combination of single-unit, multi-unit, and local field potential recording.
The relevance of this research to public health is in its advance in understanding how the visual area in the cerebral cortex works. Understanding the function of the visual cortex will aid in all aspects of treatment and diagnosis of visual disorders and mental disorders. The visual cortex is the region of the cerebral cortex that is closest to being understood, and our work is aimed at advancing this understanding. ? ? ?
|Xing, Dajun; Ouni, Ahmed; Chen, Stephanie et al. (2015) Brightness-color interactions in human early visual cortex. J Neurosci 35:2226-32|
|Xing, Dajun; Yeh, Chun-I; Gordon, James et al. (2014) Cortical brightness adaptation when darkness and brightness produce different dynamical states in the visual cortex. Proc Natl Acad Sci U S A 111:1210-5|
|Henry, Christopher A; Joshi, Siddhartha; Xing, Dajun et al. (2013) Functional characterization of the extraclassical receptive field in macaque V1: contrast, orientation, and temporal dynamics. J Neurosci 33:6230-42|
|Shapley, Robert M; Xing, Dajun (2013) Local circuit inhibition in the cerebral cortex as the source of gain control and untuned suppression. Neural Netw 37:172-81|
|Maertens, Marianne; Shapley, Robert (2013) Linking appearance to neural activity through the study of the perception of lightness in naturalistic contexts. Vis Neurosci 30:289-98|
|Lin, I-Chun; Xing, Dajun; Shapley, Robert (2012) Integrate-and-fire vs Poisson models of LGN input to V1 cortex: noisier inputs reduce orientation selectivity. J Comput Neurosci 33:559-72|
|Lee, Barry B; Shapley, Robert M; Hawken, Michael J et al. (2012) Spatial distributions of cone inputs to cells of the parvocellular pathway investigated with cone-isolating gratings. J Opt Soc Am A Opt Image Sci Vis 29:A223-32|
|Xing, Dajun; Shen, Yutai; Burns, Samuel et al. (2012) Stochastic generation of gamma-band activity in primary visual cortex of awake and anesthetized monkeys. J Neurosci 32:13873-80a|
|Xing, Dajun; Yeh, Chun-I; Burns, Samuel et al. (2012) Laminar analysis of visually evoked activity in the primary visual cortex. Proc Natl Acad Sci U S A 109:13871-6|
|Burns, Samuel P; Xing, Dajun; Shapley, Robert M (2011) Is gamma-band activity in the local field potential of V1 cortex a ""clock"" or filtered noise? J Neurosci 31:9658-64|
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