# Global Synaptic Plasticity Mechanisms in Visual Cortex

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2020 · $362,010

## Abstract

Project Summary
It is well established that experience-dependent cortical plasticity is most prominent early in life, especially in
the primary sensory cortices. However, distinct circuit components in the adult cortex retain their ability to
undergo plasticity. For example, synapses in the superficial layers of primary sensory cortices remain plastic in
adults, which contrasts thalamocortical inputs with limited plasticity. Determining the mechanisms of innate
plasticity present in the adult sensory cortices will allow us to understand how the adult brain adapts to
changes in sensory experience. We recently found evidence that in adult primary visual cortex (V1) select
excitatory synapses undergo plastic changes with rather brief alterations in sensory experience. First, we found
that brief alterations in visual experience preferentially changes the strength of lateral intracortical synapses to
layer 2/3 (L2/3) neurons without changes in the strength of feedforward inputs from layer 4 (L4). Second, we
found that deafening adults produces potentiation of thalamocortical synapses onto L4 neurons in V1 within a
week. These findings suggest that adult V1 has rather rapid innate plasticity in response to changes in sensory
experience. In this proposal, we aim to understand how specific inputs to L2/3 of adult V1 adapt to losing vision
(Aim 1), and the mechanisms underlying their subsequent recovery (Aim 2). In addition, we will determine the
mechanisms of thalamocortical synaptic plasticity elicited in adult V1 following a brief duration of deafening,
and whether it can enhance ocular dominance plasticity (ODP) (Aim 3). The results from our work will shed
light on how V1 adapts to changes in sensory experience later in life. Furthermore, our results will provide
mechanistic understanding of adult V1 plasticity, and generate molecular tools to enhance or prevent such
changes in a circuit specific manner. These developments will ultimately allow us to manipulate innate
plasticity mechanisms present in adult V1 to promote functional recovery of vision.

## Key facts

- **NIH application ID:** 9994290
- **Project number:** 5R01EY014882-17
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Hey-Kyoung Lee
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $362,010
- **Award type:** 5
- **Project period:** 2004-04-01 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9994290

## Citation

> US National Institutes of Health, RePORTER application 9994290, Global Synaptic Plasticity Mechanisms in Visual Cortex (5R01EY014882-17). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9994290. Licensed CC0.

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