The idea that the primate visual system contains parallel streams of processing that arise in the retina remain relatively independent throughout visual cortex has recently commanded considerable attention, and has led to far-reaching speculation about its functional consequences, Parallel organization is obvious at all levels of the geniculocortical system, including the sub-cortical pathway leading to cortex, the early stages of cortex, and the highest levels of cortical processing. However, the mapping of parallel components in one level onto those at the next has not been established conclusively. It is not known whether components in each stage map directly onto those at the next level, creating truly parallel pathways, or if instead a gradual intermixing eliminates any exclusive relationship between components in the different stages. While many lines of evidence suggest that the geniculocortical system in fact does contains largely independent pathways. there is also clear evidence of intermixing. The proposed experiments will continue on-going work that is aimed at evaluating the degree of parallel organization in monkey visual cortex. Conclusive answers cannot be provided either by anatomical studies or by those that examine similarities in response properties at different levels. Instead, the proposed experiments will record from cortical cells while reversibly inactivating individual magnocellular or parvocellular layers in the lateral geniculate nucleus (LGN). This is a method that the investigators have applied successfully to demonstrate that neurons in the middle temporal visual area (MT) depend primarily on the magnocellular layers on the LGN for their excitatory drive. The proposed experiments will address several specific questions about segregation of magnocellular (M channel) and parvocellular (P channel) contributions to visual cortex. 1) Does the degree of P and M channel segregation seen at the level of MT persist throughout visual cortex, or does it gradually erode in later stages? 2) Given that the P and M channels have been shown to mix to some extent, what are the special properties conferred by mixing? 3) How are the (two) P and M channels distributed across the three pathways that have been identified in the early stages of visual cortex using cytochrome oxidase stain?

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY005911-05
Application #
3261594
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1986-09-01
Project End
1994-08-31
Budget Start
1990-09-01
Budget End
1991-08-31
Support Year
5
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Rochester
Department
Type
Schools of Dentistry
DUNS #
208469486
City
Rochester
State
NY
Country
United States
Zip Code
14627
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Mayo, J Patrick; Maunsell, John H R (2016) Graded Neuronal Modulations Related to Visual Spatial Attention. J Neurosci 36:5353-61
Verhoef, Bram-Ernst; Maunsell, John Hr (2016) Attention operates uniformly throughout the classical receptive field and the surround. Elife 5:
Luo, Thomas Zhihao; Maunsell, John H R (2015) Neuronal Modulations in Visual Cortex Are Associated with Only One of Multiple Components of Attention. Neuron 86:1182-8
Ray, Supratim; Maunsell, John H R (2015) Do gamma oscillations play a role in cerebral cortex? Trends Cogn Sci 19:78-85
Mayo, J Patrick; Cohen, Marlene R; Maunsell, John H R (2015) A Refined Neuronal Population Measure of Visual Attention. PLoS One 10:e0136570
Histed, Mark H; Ni, Amy M; Maunsell, John H R (2013) Insights into cortical mechanisms of behavior from microstimulation experiments. Prog Neurobiol 103:115-30
Glickfeld, Lindsey L; Histed, Mark H; Maunsell, John H R (2013) Mouse primary visual cortex is used to detect both orientation and contrast changes. J Neurosci 33:19416-22

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