# Optical thalamic prosthesis analog for investigating V1 plasticity in blind adult mice

> **NIH NIH R21** · JOHNS HOPKINS UNIVERSITY · 2024 · $204,688

## Abstract

Project Summary
 Much research is being done to develop effective neuroprosthetic devices to recover a lost sense.
However, even in the case of a prominent success, such as the artificial cochlear implant devices used for
recovering hearing, the outcome can be limited when the implantation is done later in life. This is often
attributed to the reduced plasticity capacity of the adult brain. This is exacerbated by the fact that even with the
best engineering efforts, neuroprosthetic devices are far from providing the rich array of sensory information
that is generated by the sensory organs. This is largely due to the limited number of electrode contact points,
but also confounded by the difficulties of decoding sensory signals amidst a noisy background. Thus, the
neural activity generated by the sensory prosthetic devices are generally distorted and degraded compared to
those from intact sensory organs. For the brain to effectively utilize information arising from sensory prosthetic
devices, it then becomes essential to rewire the circuitry for optimal processing of the distorted signals.
Blindness can result from various causes but usually spares the thalamocortical circuitry, which can be used as
a substrate to convey artificial signals from visual prostheses to the cortex. Here we propose to utilize a novel
optical thalamic prosthesis analog to examine whether the primary visual cortex (V1) of blind adult mice can be
reconfigured to process artificially generated signals. By combining cutting-edge neurophotonic tools, we
developed a thalamic visual prosthesis analog by coupling an optical fiber bundle to a GRIN (gradient index)
lens implanted in the visual thalamus (dLGN, dorsal lateral geniculate nucleus) of blind adult mice. To activate
dLGN neurons using photo-stimulation, we expressed a channelrhodopsin variant in the dLGN neurons. We
have preliminary data that neurons in V1 responds to photo-stimulation of discrete dLGN locations. In this
proposal, we aim to test whether V1 in blind adult mice express sufficient plasticity to form new representations
based on artificial correlations generated from the optical thalamic prosthesis analog. And whether blind adult
mice can learn to detect and discriminate such artificial patterns of thalamic activation to guide behavior. Our
work can be extended to examine the parameters of the artificial signals generated from the optical thalamic
prosthesis analog needed for adult V1 to respond optimally and produce plasticity, as well as determine its
usefulness in guiding naturalistic behavior in blind adults. If successful, the results from our work will
demonstrate the extent of V1 plasticity and learned behavior that can result from artificial signals, which can
benefit future development of effective visual prosthetic devices for recovering vision in blind adults.

## Key facts

- **NIH application ID:** 10770457
- **Project number:** 5R21EY034297-02
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Hey-Kyoung Lee
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $204,688
- **Award type:** 5
- **Project period:** 2023-02-01 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10770457

## Citation

> US National Institutes of Health, RePORTER application 10770457, Optical thalamic prosthesis analog for investigating V1 plasticity in blind adult mice (5R21EY034297-02). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10770457. Licensed CC0.

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