# In Vivo Synaptic Imaging in Neocortex

> **NIH NIH R21** · CARNEGIE-MELLON UNIVERSITY · 2021 · $182,316

## Abstract

ABSTRACT
Synapse addition and loss have been linked to learning throughout the brain. This has been
well-documented in the neocortex using anatomical analysis of axonal boutons or dendritic
spines in both fixed tissue and in vivo, using longitudinal imaging. However, it has been difficult
to extrapolate the consequences of these synaptic changes without understanding how they lie
within a defined network of cell-type specific contacts, requiring identification of the pre- and
postsynaptic partners of the synapse. Here we will use in vivo imaging and multicolor
fluorescence labeling of molecularly-defined pre- and postsynaptic neurons to monitor input-
specific synapse addition and loss during sensory learning in a whisker-dependent task in mice.
Synaptic contacts will be validated using post-hoc expansion microscopy and
immunohistochemistry for nanoscale resolution. Analysis will be focused on learning-dependent
reorganization of thalamic inputs from a higher-order thalamic nucleus, the posterior medial
nucleus (POm) onto the dendrites of layer 5 (L5) pyramidal neurons that have been specifically
implicated in experience-dependent plasticity. Quantitative, multicolor, in vivo imaging across
different stages of learning will provide insight into how cortical circuits encode and are changed
by salient sensory information.

## Key facts

- **NIH application ID:** 10156745
- **Project number:** 1R21MH123906-01A1
- **Recipient organization:** CARNEGIE-MELLON UNIVERSITY
- **Principal Investigator:** ALISON L BARTH
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $182,316
- **Award type:** 1
- **Project period:** 2021-09-01 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10156745

## Citation

> US National Institutes of Health, RePORTER application 10156745, In Vivo Synaptic Imaging in Neocortex (1R21MH123906-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10156745. Licensed CC0.

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