The long-term objective of this research is to determine how central visual pathways in the brain encode and transmit spatial and temporal information. The proposed project utilizes neurophysiological methods to record from single neurons or from small groups of cells in striate and parastriate visual cortex. (1) Intercellular connections: (a) A hypothesis will be tested that simple-to-simple cell communication underlies direction selectivity. (b) Predictions of a disparity energy model will be explored by recording simultaneously from binocular simple and complex cells. (c) Different processing levels will be investigated for members of complex-to-complex cell pairs. (d) A conjecture will be addressed that phase disparity tuning of neighboring complex cells involves quadrature encoding. (2) Functional properties of area 18: (a) Contrast sensitivities and dynamic ranges will be compared in areas 17 and 18. (b) A hypothesis will be examined that near and far cell function in area 18 may be accounted for by a disparity energy model. (c) the joint processing of motion and depth will be investigated. (d) Temporal tuning, timing, and filtering characteristics will be determined. (e) An analysis of nonlinear function will be made by using white noise stimuli. (3) Center-surround receptive field organization: (a) Surround characteristics will be examined to determine spatial distributions and properties. (b) Timing characteristics between center and surround will be explored to examine the hypothesis that surround inhibition arises from local intracortical connections. (c) A hypothesis will be tested that surround suppression participates in contrast normalization. (d) A possibility will be explored that surround suppression is part of the near and far disparity encoding process. These investigations will provide fundamental insights into receptive field organization and neural circuitry in the visual system. This basic information about normal visual function will help form a framework for the diagnosis and treatment of visual disorders.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY001175-31
Application #
6654941
Study Section
Visual Sciences B Study Section (VISB)
Program Officer
Oberdorfer, Michael
Project Start
1976-08-01
Project End
2004-07-31
Budget Start
2003-08-01
Budget End
2004-07-31
Support Year
31
Fiscal Year
2003
Total Cost
$356,185
Indirect Cost
Name
University of California Berkeley
Department
Type
Schools of Optometry/Ophthalmol
DUNS #
124726725
City
Berkeley
State
CA
Country
United States
Zip Code
94704
Kim, Taekjun; Freeman, Ralph D (2017) Binocular function during unequal monocular input. Eur J Neurosci 45:601-609
Freeman, Ralph D (2017) 2015 Charles F. Prentice Medal Award Lecture: Neural Organization of Binocular Vision. Optom Vis Sci 94:931-938
Kim, Taekjun; Freeman, Ralph D (2016) Direction selectivity of neurons in the visual cortex is non-linear and lamina-dependent. Eur J Neurosci 43:1389-99
Li, Baowang; Freeman, Ralph D (2015) Neurometabolic coupling between neural activity, glucose, and lactate in activated visual cortex. J Neurochem 135:742-54
Kim, Taekjun; Allen, Elena A; Pasley, Brian N et al. (2015) Transcranial Magnetic Stimulation Changes Response Selectivity of Neurons in the Visual Cortex. Brain Stimul 8:613-23
Moore 4th, Bartlett D; Rathbun, Daniel L; Usrey, W Martin et al. (2014) Spatiotemporal flow of information in the early visual pathway. Eur J Neurosci 39:593-601
Kim, T; Freeman, R D (2014) Selective stimulation of neurons in visual cortex enables segregation of slow and fast connections. Neuroscience 274:170-86
Li, B; Freeman, R D (2013) Binocular activation elicits differences in neurometabolic coupling in visual cortex. Neuroscience 248:529-40
Moore 4th, Bartlett D; Freeman, Ralph D (2012) Development of orientation tuning in simple cells of primary visual cortex. J Neurophysiol 107:2506-16
Li, B; Freeman, R D (2012) Spatial summation of neurometabolic coupling in the central visual pathway. Neuroscience 213:112-21

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