# Organization and Development of Functional Maps in Visual Cortex

> **NIH NIH R01** · MAX PLANCK FLORIDA CORPORATION · 2023 · $482,500

## Abstract

Project Summary/Abstract
Establishing how features of the visual world are represented in the activity of cortical circuits, and how these
representations are constructed during development remain fundamental challenges for visual neuroscience and
are central to understanding the neural basis of visual perception. A critical function of circuits in primary visual
cortex is the integration of the inputs from the two eyes to create a single binocularly aligned columnar
representation of stimulus features such as the orientation of edges and their direction of motion. This alignment
is evident at the scale of columns, and at the scale of individual neurons: visual stimuli presented to either eye
yield highly similar responses at both scales, giving rise to our coherent binocular perception of the world. Our
studies during the previous period of support have revealed a surprising new and critical role for visual
experience in the development of binocularly aligned columnar representations in ferret visual cortex. Prior to
natural eye opening, visual stimulation thru either eye evokes highly structured columnar maps of orientation
preference, but there are conspicuous mismatches in the spatial organization of these maps that reflect
misalignment in the orientation preference of the inputs that individual neurons receive from the two eyes. Shared
binocular experience immediately following eye opening is necessary to drive changes in the orientation
preference of individual neurons that achieve a single binocularly unified representation. The goal of this proposal
is to employ new technologies that we have developed that make it possible to visualize the functional
organization of excitatory synaptic inputs to individual neurons in order to probe the mechanisms responsible for
this alignment process. We start in Aim 1 by examining the synaptic basis for binocular integration in the mature
visual cortex, combining 2-photon in vivo imaging of calcium signals with post-hoc electron microscopy to
elucidate how the numbers, strength, and the spatial arrangement of functionally characterized synapses
contribute to the binocular response properties of individual layer 2/3 neurons. In Aim 2, we examine the
functional synaptic architecture of binocular integration early in development and use chronic imaging techniques
to probe changes induced by the onset of visual experience. In Aim 3 we combine in vivo imaging with expansion
microscopy to explore how 2 major sources of inputs to layer 2/3—feedforward inputs from layer 4, and horizontal
connections from other layer 2/3 neurons--contribute to the mature pattern of binocular integration and to the
development of binocularly aligned representations. Taken together, we believe these experiments will yield a
wealth of new insights into the synaptic basis for binocular integration and the experience-dependent
mechanisms that achieve aligned representations in visual cortex.

## Key facts

- **NIH application ID:** 10541121
- **Project number:** 5R01EY011488-24
- **Recipient organization:** MAX PLANCK FLORIDA CORPORATION
- **Principal Investigator:** DAVID FITZPATRICK
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $482,500
- **Award type:** 5
- **Project period:** 1996-08-01 → 2024-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10541121

## Citation

> US National Institutes of Health, RePORTER application 10541121, Organization and Development of Functional Maps in Visual Cortex (5R01EY011488-24). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10541121. Licensed CC0.

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