# The functional role of corticogeniculate feedback in vision

> **NIH NIH R01** · UNIVERSITY OF ROCHESTER · 2022 · $473,503

## Abstract

Corticothalamic circuits linking the primary sensory cortex with the primary sensory thalamus in the feedback
direction are ubiquitous across sensory modalities and mammalian species and are ideally positioned to regulate
the flow of sensory signals from periphery to cortex. However, the functional role of these circuits in sensory
perception remains a fundamental mystery in neuroscience. In the visual system, corticogeniculate neurons
provide the majority of inputs onto neurons in the dorsal lateral geniculate nucleus (LGN), however receptive
fields of LGN neurons closely resemble their retinal inputs and not their corticogeniculate inputs. Partly because
corticogeniculate influence over LGN activity is modulatory rather than driving, the functional role of
corticogeniculate feedback in vision has been difficult to characterize. The overarching goal of this proposal is to
elucidate the structural organization of corticogeniculate feedback and its functional role in visual perceptual
behavior. To accomplish this goal, intersecting and emerging technologies are employed including functional
ultrasound imaging, neurophysiological recording, optogenetics, and chemogenetics in two highly visual
mammalian species: ferrets and macaque monkeys. Building upon our previous findings that corticogeniculate
feedback regulates the timing and precision of LGN responses to visual inputs, the three Specific Aims of this
proposal address important new questions regarding the function and connectivity of corticogeniculate feedback.
Specific Aim 1 will examine whether corticogeniculate feedback regulates the temporal dynamics of LGN
neurons uniquely, depending on the type of visual feature information they convey. Specific Aim 2 will examine
the spatial extent of corticogeniculate influence over LGN population activity using a combination of functional
ultrasound and optogenetics. Aim 2 will also examine the precise functional connectivity between individual
corticogeniculate and LGN neurons to determine whether corticogeniculate circuits exert stream-specific
influence on individual LGN neurons. A major motivation behind Specific Aims 1 and 2 is to determine whether
corticogeniculate feedback regulates visual information transmission through the LGN in a stream-specific
manner or whether corticogeniculate influence is more global and diffuse. Specific Aim 3 represents a significant
step forward in understanding corticogeniculate function by testing how corticogeniculate circuits contribute to
visual discrimination behavior. We have developed a novel virus-mediated gene delivery strategy that enables
selective manipulation of corticogeniculate circuits via optogenetics or chemogenetics, applicable to long-term
behavioral experiments in ferrets. Together, results of the experiments proposed under each Aim will provide a
fuller picture of the functional role of corticogeniculate feedback in visual perception by revealing the underlying
connectivity and mechanisms giv...

## Key facts

- **NIH application ID:** 10363892
- **Project number:** 2R01EY025219-07
- **Recipient organization:** UNIVERSITY OF ROCHESTER
- **Principal Investigator:** Farran Briggs
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $473,503
- **Award type:** 2
- **Project period:** 2016-05-01 → 2027-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10363892

## Citation

> US National Institutes of Health, RePORTER application 10363892, The functional role of corticogeniculate feedback in vision (2R01EY025219-07). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10363892. Licensed CC0.

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