# Individual differences in cortical-striatal pathway utilization regulating flexibility

> **NIH NIH F32** · UNIVERSITY OF MARYLAND BALTIMORE · 2022 · $74,234

## Abstract

Project Summary
Addiction is a multifaceted, chronic neurobiological disorder occurring in only 15-30% of individuals who
experiment with drugs of abuse. This individual variability suggests neurobiological differences present prior to
any drug exposure, resulting in phenotypic behavioral differences across species. In rats, addiction-resistant
“goal-trackers” (GT) flexibly adjust behavior when an outcome is devalued, independent of extent of training.
Addiction-vulnerable “sign-trackers” (ST) fail to adjust their behavior and persistently show increased responding
to learned cues despite outcome devaluation. I recently found this inflexibility in ST rats is only evident after
limited training, as they become behaviorally flexible, similar to GT rats, after extended training. These transient
behavioral differences suggest dissociable neurobiological mechanisms between phenotypes and across
training. The long-term goal of this project is to understand the neurobiological differences underlying behavioral
differences in addiction vulnerability phenotypes, and how these behavioral and neural differences change with
training. I recently found communication between the anterior insular cortex (aIC) to nucleus accumbens core
(NAcC) is necessary for outcome devaluation, specifically in GT rats, but not in ST rats. The aim of the current
proposal is to examine how activation, excitability, and synaptic plasticity of the aICNAcC pathway mediates
tracking- and experience-dependent behavioral flexibility. I hypothesize increased utilization of the aICNAcC
pathway in GT rats compared to ST rats that regulates behavioral flexibility across training. In Aim 1, I will use
pathway-specific chemogenetics to test the necessity and sufficiency of the aICNAcC pathway in outcome
devaluation across training in GT and ST rats. In Aim 2, I will use ex vivo electrophysiological recordings in
combination with pathway tracing and optogenetics to determine excitability and synaptic differences within the
aICNAcC pathway between GT and ST rats after outcome devaluation. In Aim 3, I will use in vivo
electrophysiological recordings in combination with optogenetics to measure real-time activity of the aICNAcC
pathway in GT and ST during outcome devaluation. Investigating how the aICNAcC pathway mediates
tracking- and experience-dependent differences in behavioral flexibility is necessary to further our understanding
of neurobiological mechanisms that predispose individuals to addiction vulnerability prior to drug experience.
The proposed experiments will advance my use of electrophysiological techniques and analysis of complex
datasets. This application draws on the strong addiction expertise of faculty at University of Maryland School of
Medicine to foster successful completion of the proposed training plan. Together, my proposed aims along with
the strong mentorship and collaborative nature of my department ensures successful development as an
independent scientist.

## Key facts

- **NIH application ID:** 10379945
- **Project number:** 5F32DA053772-02
- **Recipient organization:** UNIVERSITY OF MARYLAND BALTIMORE
- **Principal Investigator:** Sara Keefer
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $74,234
- **Award type:** 5
- **Project period:** 2021-04-01 → 2024-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10379945

## Citation

> US National Institutes of Health, RePORTER application 10379945, Individual differences in cortical-striatal pathway utilization regulating flexibility (5F32DA053772-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10379945. Licensed CC0.

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