For sensory systems, feedforward projections from thalamic relay cells provide the cortex with information about the external environment. The cortex, in turn, sends extensive feedback to the thalamus. The cortex thus functions both to process information supplied by the thalamus as well as to influence dynamically the transmission of thalamic input. The primary goal of the experiments presented in this proposal is to determine how the primary visual cortex (V1) and the lateral geniculate nucleus (LGN) of the thalamus interact to dynamically influence visual processing. The study involves three sets of experiments. The first major series of experiments (Specific Aim 1) will test the hypothesis that corticogeniculate feedback serves to increase the strength and temporal precision of LGN responses to visual stimuli. The remaining experiments go on to test the exciting possibility that corticogeniculate feedback dynamically adjusts feedforward activity and functional connectivity to meet the behavioral and perceptual demands that occur during visual processing. The second major series of experiments (Specific Aim 2) will test the hypothesis that directed attention influences the dynamic properties of feedforward and feedback pathways interconnecting the LGN and V1. The third major series of experiments (Specific Aim 3) will test the hypothesis that perceptual modulation during binocular rivalry influences neuronal activity in the LGN and the dynamic properties of feedforward and feedback connectivity. Given the central importance of corticothalamic pathways for governing the excitability of thalamocortical networks, it is important that we understand the functional properties of the corticothalamic pathway, as disorders of the pathway likely underlie several illnesses affecting vision and visual processing.

Public Health Relevance

A reciprocal arrangement of neuronal connections governs the excitability of neurons in the thalamus and cerebral cortex. Given the severe financial and quality-of-life consequences that follow from disruption in the ability of these brain regions to communicate with each other, such as occurs with many forms of epilepsy and several illnesses affecting vision and visual processing, it is important that we gain a better understanding of thei functional relationship. The goal of this proposal is to determine how the cortex and thalamus interact to dynamically influence visual processing.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY013588-13
Application #
8731239
Study Section
(SPC)
Program Officer
Araj, Houmam H
Project Start
2001-07-05
Project End
2017-07-31
Budget Start
2014-08-01
Budget End
2015-07-31
Support Year
13
Fiscal Year
2014
Total Cost
Indirect Cost
Name
University of California Davis
Department
Neurology
Type
Schools of Medicine
DUNS #
City
Davis
State
CA
Country
United States
Zip Code
95618
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Hembrook-Short, Jacqueline R; Mock, Vanessa L; Briggs, Farran (2017) Attentional Modulation of Neuronal Activity Depends on Neuronal Feature Selectivity. Curr Biol 27:1878-1887.e5
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Bragg, Elise M; Briggs, Farran (2017) Large-scale Reconstructions and Independent, Unbiased Clustering Based on Morphological Metrics to Classify Neurons in Selective Populations. J Vis Exp :
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Briggs, Farran; Kiley, Caitlin W; Callaway, Edward M et al. (2016) Morphological Substrates for Parallel Streams of Corticogeniculate Feedback Originating in Both V1 and V2 of the Macaque Monkey. Neuron 90:388-99
Usrey, W Martin; Alitto, Henry J (2015) Visual Functions of the Thalamus. Annu Rev Vis Sci 1:351-371
Alitto, Henry J; Usrey, W Martin (2015) Surround suppression and temporal processing of visual signals. J Neurophysiol 113:2605-17
Bastos, Andre M; Briggs, Farran; Alitto, Henry J et al. (2014) Simultaneous recordings from the primary visual cortex and lateral geniculate nucleus reveal rhythmic interactions and a cortical source for ?-band oscillations. J Neurosci 34:7639-44

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