# Taste and Oral Sensory Processing in the Brain

> **NIH NIH R01** · UNIVERSITY OF OKLAHOMA · 2020 · $327,727

## Abstract

Flavor is implicated to guide ingestive decisions that impact nutritional status and can lead to health problems
in humans, such as obesity and diabetes. Flavor involves the actions of multiple sensory pathways, including
neural circuits that invoke taste sensations, such as sweet and bitter, and those that give rise to oral
somatosensation. Somatosensory cues elicited by foods can include temperature and pain (e.g., chili pepper
burn). Neural messages about oral somatosensation are partly signaled by electrical activity in the fifth cranial
nerve and brain nuclei known as the trigeminal system. The involvement of brain trigeminal pathways in flavor
is poorly understood and many questions remain, including how central trigeminal neurons signal information
about noxious and innocuous oral temperature. The proposed research will address this and other questions
with the long-term goal of elucidating how orosensory trigeminal neurons contribute to and perform unimodal
and multisensory processing relevant to flavor. Specific Aim #1 will use neurophysiological recordings from
single trigeminal neurons in the mouse medulla to test the hypothesis that heterogeneous subpopulations of
cells distinguish noxious from innocuous oral temperatures, focusing on the neural representation of oral
cooling. Cellular function will be gauged by using antidromic electrical activation to verify projections of
recorded neurons to the parabrachial nucleus, which is involved with integrative and affective processing. To
define afferent inputs that reach different types of cooling-responsive orosensory cells, units will be tested with
chemical agonists of transient receptor potential (TRP) ion channels that mediate thermosensation and
nociception, and also recorded from mice genetically deficient for a select TRP channel implicated for cooling
sensation. Specific Aim #2 will test the hypothesis that the parabrachial nucleus is a brain site of logical
trigeminal and taste integration. Interaction between taste and trigeminal pathways has been discussed to
contribute to flavor perception, albeit brain neurons that support merger of gustatory and trigeminal sensory
signals remain undefined. There are scant anatomical and physiological data to suggest convergence of taste
and trigeminal pathways arises in the parabrachial nucleus, which has been studied for separate roles in taste
or pain processing. Here, we will use neurophysiological recording, stimulation, and optogenetic techniques
that afford rapid and reversible inhibition of neural activity to dissect whether and how neuronal projections
from medullary trigeminal nuclei reach gustatory-responsive neurons in the parabrachial nucleus. Genetically
TRP-deficient mice will also be tested in recording studies to index receptors mediating somatosensory activity
in parabrachial gustatory cells. Finally, we will apply optogenetics to assess how primary trigeminal afferents
that reach the parabrachial nucleus interact with gusta...

## Key facts

- **NIH application ID:** 9872148
- **Project number:** 5R01DC011579-10
- **Recipient organization:** UNIVERSITY OF OKLAHOMA
- **Principal Investigator:** CHRISTIAN H LEMON
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $327,727
- **Award type:** 5
- **Project period:** 2011-03-01 → 2022-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9872148

## Citation

> US National Institutes of Health, RePORTER application 9872148, Taste and Oral Sensory Processing in the Brain (5R01DC011579-10). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9872148. Licensed CC0.

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