# Mapping GC topographic organization using 2-photon calcium imaging in alert mice

> **NIH NIH R21** · STATE UNIVERSITY NEW YORK STONY BROOK · 2020 · $199,375

## Abstract

PROJECT SUMMARY
 The gustatory cortex (GC) has been the subject of great attention over the past years. While its role in
processing taste is well established, several issues regarding the strategy used by GC for coding gustatory
information remain unsolved. The recent adoption of 2-photon calcium imaging to map the surface of GC in
anesthetized mice has highlighted the possibility that gustatory information may be encoded by spatial patterns
of single neuron activity. An influential proposal suggested a “gustotopic” organization of taste coding, featuring
spatially localized “hot spots” formed by single clusters of neurons responding exclusively to a single taste quality.
More recent imaging data complemented, and partially challenged this hypothesis, by showing spatially
distributed representations in portions of GC between hotspots. Alas, both the studies published so far were
performed in anesthetized animals. The impervious anatomical location of GC has hindered the application of 2-
photon calcium imaging to study the topographical organization GC in alert mice. As a result, the nature of spatial
coding in alert animals remains unknown.
 The research proposed in this grant will establish the experimental protocols for imaging large ensembles of
neurons from the surface of GC in alert mice. The proposed research focuses on the following aims: Aim #1 will
establish the methods for 2-photon calcium imaging using microprisms implanted on the surface of GC in mice
licking for different tastants; Aim #2 will perfect the ability to monitor activity in the same ensemble for multiple
days; Aim #3 will combine calcium imaging with behavioral training to monitor neural activity in mice engaged in
taste discriminations. In addition to achieving technical milestones, the experiments in each aim will also address
important scientific questions. Specifically, Aim #1 will investigate spatial patterns of activity on the surface of
GC, addressing how wakefulness affects gustotopy and introduces temporal dynamics. Aim #2 will investigate
the balance between plasticity and stability in GC representations, addressing how familiarization and repeated
exposure affect taste evoked activity. Finally, Aim #3 will unveil the relationship between spatio-temporal
patterns of activity and perception, by imaging GC in mice learning and performing simple and difficult
discriminations in a taste-based, two alternative forced choice task.
 Altogether, the proposed experiments will answer fundamental questions in the field of gustation and open an
entirely new research pipeline for future studies. Future studies made possible by this approach will investigate
GC responses to multiple stimuli (multiple tastants, odors, flavors and cross-modal cues), unveil whether
anticipatory cues can recruit taste representations and investigate coding in different cell types.

## Key facts

- **NIH application ID:** 9828765
- **Project number:** 5R21DC017681-02
- **Recipient organization:** STATE UNIVERSITY NEW YORK STONY BROOK
- **Principal Investigator:** Alfredo Fontanini
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $199,375
- **Award type:** 5
- **Project period:** 2018-12-01 → 2021-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9828765

## Citation

> US National Institutes of Health, RePORTER application 9828765, Mapping GC topographic organization using 2-photon calcium imaging in alert mice (5R21DC017681-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9828765. Licensed CC0.

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