# An innovative approach to cracking odor coding in the piriform cortex

> **NIH NIH R21** · FLORIDA STATE UNIVERSITY · 2024 · $423,500

## Abstract

Project Summary
As the largest cortical recipient of direct olfactory bulb (OB) projections and a prominent part of the rodent brain, the
piriform cortex (PCx) is considered to be a central hub for the processing and coding of olfactory information. While
landmark studies have made significant progress towards deciphering PCx odor coding, there remains (in many cases) a
significant disconnect between our understanding of olfactory perception and the coding principles that underlie it. For
example, the PCx exhibits a massive over-representation of identity information that appears disproportional to the number
of glomerular inputs necessary to encode odor features or drive odor-guided behavior. The efficient coding hypothesis
predicts that in a low-noise situation (i.e., one with sparse receptor activation), the neuronal population should remove
redundancies in order to most efficiently encode the stimulus. In a high noise situation (i.e., one with significant non-target
receptor activation), the system should attempt to encode the stimulus in the most robust manner possible, by becoming
highly redundant. Thus far, the stimulus concentrations utilized to examine PCx neural activity are typically many orders of
magnitude above natural odorant concentrations - potentially signifying that these coding principles have been examined
primarily in high neural noise situations. The ability to examine PCx neural activity within sparse receptor activation
regimes will ultimately require knowledge about the limits of perceptual sensitivity and necessitate analyzing odor-evoked
responses at both single neuron and ensemble levels. Here, we propose a technically innovative approach that will refine
the current model of PCx odor coding. Specific Aim 1 will examine how the neural dynamics of individual and ensemble
PCx neurons encode odor identity across different concentration regimes by utilizing high density recording across eight
PCx locations, spanning a total A-P distance of 2.7mm. Specific Aim 2 will utilize the same electrophysiological approach
in conjunction with our robust behavioral measures of sensitivity to investigate how the coding principles identified in Aim
1 predict perceptual ability. Achieving these aims will offer a unique and unparalleled window into odor processing by
analyzing PCx neural activity at both local and mesoscale levels, across different concentration regimes, in a manner that
can be correlated to perception.

## Key facts

- **NIH application ID:** 11057296
- **Project number:** 1R21DC021776-01A1
- **Recipient organization:** FLORIDA STATE UNIVERSITY
- **Principal Investigator:** Adam Kabir Dewan
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $423,500
- **Award type:** 1
- **Project period:** 2024-09-24 → 2026-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11057296

## Citation

> US National Institutes of Health, RePORTER application 11057296, An innovative approach to cracking odor coding in the piriform cortex (1R21DC021776-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/11057296. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*