In our working model of visual information processing, we hypothesize that there are three segregated parallel pathways [magnocellular (M), parvocellular (P), and koniocelIular (K)] from the lateral genicuIate nucleus (LGN) to primary visual cortex (V1), forming both dedicated and multi-functional systems and networks. Within this scheme, separate output layers and compartments of V1 have distinct modes for utilizing signals from all three input pathways and generating output signals that contribute to the dynamics and functional maps of extrastriate areas. In light of this model, the major effort of our project is to understand how parallel LGN pathways in primates contributes to the properties of V1 and its extrastriate targets. This proposal focuses on all three LGN relays and how their inputs affect V1 and higher visual centers, but places added emphasis on the K pathway considering the fact that it has been, until recently, largely ignored.
Our specific aims are designed to test hypotheses generated by our working model.
In Aim I, we will determine the number of physiologically distinct K channels and the classes of retinal ganglion ceils that project to K LGN layers.
In Aim II, we will determine the relationship between LGN relay cells and the dynamics and functional maps found within V1.
In Aim III, we will apply the same techniques utilized in Aim II to determine how LGN relays contribute to the dynamics and functional maps found within extrastriate areas V2, V3, and DM/V3a. The results of our proposed studies will contribute important new information to our understanding of the fundamentals of how the brain processes visual information and of brain architecture in general.
| Jiang, Yaoguang; Purushothaman, Gopathy; Casagrande, Vivien A (2015) A computational relationship between thalamic sensory neural responses and contrast perception. Front Neural Circuits 9:54 |
| Jiang, Yaoguang; Yampolsky, Dmitry; Purushothaman, Gopathy et al. (2015) Perceptual decision related activity in the lateral geniculate nucleus. J Neurophysiol 114:717-35 |
| Jiang, Yaoguang; Purushothaman, Gopathy; Casagrande, Vivien A (2015) The functional asymmetry of ON and OFF channels in the perception of contrast. J Neurophysiol 114:2816-29 |
| Purushothaman, Gopathy; Chen, Xin; Yampolsky, Dmitry et al. (2014) Neural mechanisms of coarse-to-fine discrimination in the visual cortex. J Neurophysiol 112:2822-33 |
| Shostak, Yuri; Wenger, Ashley; Mavity-Hudson, Julia et al. (2014) Metabotropic glutamate receptor 5 shows different patterns of localization within the parallel visual pathways in macaque and squirrel monkeys. Eye Brain 6:29-43 |
| Ichida, Jennifer M; Mavity-Hudson, Julia A; Casagrande, Vivien A (2014) Distinct patterns of corticogeniculate feedback to different layers of the lateral geniculate nucleus. Eye Brain 2014:57-73 |
| Marion, Roan; Li, Keji; Purushothaman, Gopathy et al. (2013) Morphological and neurochemical comparisons between pulvinar and V1 projections to V2. J Comp Neurol 521:813-32 |
| Li, K; Patel, J; Purushothaman, G et al. (2013) Retinotopic maps in the pulvinar of bush baby (Otolemur garnettii). J Comp Neurol 521:3432-50 |
| Purushothaman, Gopathy; Casagrande, Vivien A (2013) A Generalized ideal observer model for decoding sensory neural responses. Front Psychol 4:617 |
| Purushothaman, Gopathy; Marion, Roan; Li, Keji et al. (2012) Gating and control of primary visual cortex by pulvinar. Nat Neurosci 15:905-12 |
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