# REPRESENTATION OF FAMILIAR IMAGES IN VENTRAL STREAM VISUAL CORTEX

> **NIH NIH R01** · CARNEGIE-MELLON UNIVERSITY · 2021 · $443,852

## Abstract

We rely for object recognition on hierarchical processing of visual input by the ventral stream of cortical
visual areas. The chain begins in low-order cortex (including area V2) where neuronal activity represents local
features and terminates in inferotemporal cortex (including area TE) where neuronal activity represents global
images. Neuronal function in the ventral stream is subject to alteration by visual experience. One particularly
robust form of visual plasticity is familiarity suppression. Familiarity suppression can be induced in TE by
allowing subjects to view the same set of images repeatedly over the course of days and weeks. At the end of
the familiarization period, the mean strength of neuronal responses in TE is less for the familiar images than for
novel controls. On the assumption that familiarity suppression is specific to TE, it has been thought to serve
some function related to late-stage processing of the global image. Recently, however, familiarity suppression
has been shown to occur even in V2, where neurons represent local features and not entire objects. On the
basis of this observation, we propose that familiarity suppression, far from being specific to late-stage
processing of the global image, arises from principles of unsupervised statistical learning operative at each
stage of the ventral stream and expressed at each stage relative to the nature and scale of represented visual
information. We will test this general idea by using semi-chronic multielectrode arrays to monitor neuronal
population activity simultaneously in V2 and TE during image familiarization. Experiments under Aim 1 will test
the hypothesis that familiarity suppression develops independently in V2 and is not just fed back from TE.
Experiments under Aim 2 will test the hypothesis that familiarization enhances the cooperative representation
of an image by neuronal populations in V2 and TE. Experiments under Aim 3 will test the idea that the synaptic
alterations underlying the impact of familiarization obey a Hebbian learning rule.

## Key facts

- **NIH application ID:** 10077561
- **Project number:** 5R01EY030226-02
- **Recipient organization:** CARNEGIE-MELLON UNIVERSITY
- **Principal Investigator:** TAI-SING LEE
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $443,852
- **Award type:** 5
- **Project period:** 2020-01-01 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10077561

## Citation

> US National Institutes of Health, RePORTER application 10077561, REPRESENTATION OF FAMILIAR IMAGES IN VENTRAL STREAM VISUAL CORTEX (5R01EY030226-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10077561. Licensed CC0.

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