# Neural circuitry underlying individual differences in cue-driven reward-seeking behavior

> **NIH NIH R03** · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · 2020 · $78,250

## Abstract

Project Summary
Cues that are repeatedly associated with rewards, such as food or drugs of abuse, can exert a powerful influence
over behavior. They can elicit approach or interaction even when such behavior is maladaptive – e.g., the sight
of drug paraphernalia might prompt approach by an addict in recovery. Notably, the ability of reward-associated
cues to produce approach and/or interaction varies widely among individuals; for example, if a cue (e.g.,
extension of a lever) predicts a reward in a different location (e.g. a sugar pellet delivered to a food cup), some
rats will preferentially approach and interact with the lever – a behavior known as sign tracking (ST) – and others
will approach the site of reward delivery, a behavior known as goal tracking (GT). A propensity towards ST has
been linked to susceptibility to drug-taking, relapse, and related behaviors. In addition, the neurobiological basis
of sign tracking has much in common with brain processes underlying drug use, addiction, and relapse. Both ST
and addiction are highly dependent on dopaminergic transmission in the mesocorticolimbic circuit, and especially
on dopamine release in the nucleus accumbens (NAc). Moreover, sign trackers and goal trackers show distinct
patterns of NAc dopamine release during the acquisition of reward-seeking behavior, implying that ST and GT
behavior may engage different circuits – one dopamine-dependent, and one not – for associative learning.
Despite the links among ST, drug abuse, and NAc dopamine release, we know little about the responses of
individual NAc neurons during a typical ST/GT protocol, including whether they differ among individual animals
that express ST or GT behavior. Moreover, it remains unclear how the differences in NAc dopamine release in
sign trackers and goal trackers impact neural signaling in the accumbens in a way that supports one form of
learning over another. Therefore, we propose a set of experiments to compare neural activity in the NAc during
acquisition, maintenance, and extinction of reward-seeking behavior among individuals with a propensity towards
sign tracking or goal tracking. To do so, we will combine electrophysiological and optogenetic approaches: first,
we will record the activity of individual neurons in the NAc during key phases of an ST/GT protocol. Then, using
projection-specific optogenetic techniques, we will selectively stimulate dopamine release in the NAc during
acquisition or maintenance of ST/GT behavior. By stimulating during the cue or the reward on a subset of trials,
we can assess the timing-specific impact of dopamine release on acquisition and expression of ST and GT, and
– using concurrent stimulation and recording – ST/GT-related neural signaling in the NAc. The results may have
important implications for our understanding of the convergence and divergence of the parallel neural learning
systems thought to underlie ST and GT behavior. Furthermore, by uncovering differences in neural proces...

## Key facts

- **NIH application ID:** 9861234
- **Project number:** 5R03DA045913-02
- **Recipient organization:** UNIVERSITY OF PITTSBURGH AT PITTSBURGH
- **Principal Investigator:** Sara Morrison
- **Activity code:** R03 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $78,250
- **Award type:** 5
- **Project period:** 2019-02-15 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9861234

## Citation

> US National Institutes of Health, RePORTER application 9861234, Neural circuitry underlying individual differences in cue-driven reward-seeking behavior (5R03DA045913-02). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/9861234. Licensed CC0.

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