Summary: Researchers investigating risky decision-making in rats discovered that a reward-related neural circuit influences impulsivity and risk-taking in distinct ways depending on when it is engaged and the biological sex of the animal. Modulating this circuit during the learning phase of a gambling task changed choice preferences differently in males and females, while manipulating the same circuit after the task was learned primarily affected motor impulsivity in both sexes.
These findings show that a single brain system can produce different behavioral outcomes depending on timing and sex. The study implies that treatments for disorders involving impulsivity—such as addiction or attention-deficit/hyperactivity disorder—may be more effective if they account for sex differences and the stage of learning or illness when an intervention is applied.
Key Facts
- Timing matters: Altering the same neural circuit during task acquisition versus after stable performance produced different effects on risk-taking and impulsivity.
- Sex differences: The circuit’s influence on risky decision-making showed distinct patterns in male and female rats.
- Clinical relevance: The results support the idea that sex-specific and stage-dependent approaches may improve treatments for impulsivity-related disorders.
Source: SfN
Background: Some people with psychiatric conditions, including addiction and attention-deficit/hyperactivity disorder (ADHD), have difficulty controlling impulses or making decisions under uncertainty. To better understand how brain circuits shape these behaviors, researchers examined a population of reward-related neurons in rats engaged in a gambling-style decision task.
In a collaboration between the University of Cambridge and the University of British Columbia, Tristan Hynes and colleagues used a rodent gambling task to study how a specific group of neurons in the ventral striatum contributes to both impulsivity and risky choice. The rats chose among four holes that differed in the probability of delivering a reward or a time-out penalty, enabling simultaneous measurement of decision-making under risk and motor impulsivity.
The team used chemogenetic tools to either activate or inhibit ventral striatal cholinergic interneurons (vsCINs) at two different stages: during task acquisition and after the animals had established a stable choice strategy. Manipulating vsCINs during learning shifted risk preferences in a sex-dependent way, whereas manipulating them after learning primarily affected the tendency to make premature responses (motor impulsivity) in both males and females.
Put simply, the same neural circuit guided different behavioral processes depending on the learning stage and the animal’s sex. When engaged during acquisition, vsCINs appeared to shape how rats learned reward contingencies and adopted risky or conservative strategies; when engaged after learning, the circuit exerted greater control over the suppression of premature actions.
Tristan Hynes explains that these results emphasize the context-dependent and sex-specific nature of neural circuit function. They argue against uniform, one-size-fits-all pharmacological strategies and encourage consideration of both sex and the behavioral stage when designing or timing interventions for impulsivity-related disorders.
Key Questions Answered:
A: The study focused on a reward-related circuit in the ventral striatum—specifically ventral striatal cholinergic interneurons—that influences decision-making under risk and motor impulsivity.
A: Manipulating the circuit during task acquisition altered risky choice behavior (with sex-specific patterns), while manipulating it after behavior was stable mainly affected motor impulsivity in both sexes.
A: Because the same circuit produces different effects depending on learning stage and sex, personalized, sex-aware, and stage-specific treatment strategies may be required to more effectively address impulsivity-related conditions.
About this neuroscience research news
Author: SfN Media
Source: SfN
Contact: SfN Media – SfN
Image: The image is credited to Neuroscience News
Original Research: Closed access.
Title: “Ventral Striatal Cholinergic Interneurons Regulate Decision-Making or Motor Impulsivity Differentially Across Learning and Biological Sex” by Tristan Hynes et al., published in the Journal of Neuroscience.
Abstract
Ventral Striatal Cholinergic Interneurons Regulate Decision-Making or Motor Impulsivity Differentially Across Learning and Biological Sex
Dopaminergic signaling in the ventral striatum has long been linked to both risk/reward decision-making and impulse control. The rat gambling task (rGT) provides concurrent measures of risky choice and motor impulsivity, allowing researchers to examine how these behaviors interact and how neuromodulatory systems influence them across learning.
Although risky choice and impulsivity can correlate at the population level, manipulations of dopamine-related systems do not always affect both behaviors in the same way. Prior work suggests that dopaminergic effects on choice are more pronounced when transmission is altered during task acquisition, whereas changes in motor impulsivity can be more evident after a decision strategy is established.
Striatal cholinergic interneurons (CINs) shape reinforcement learning by modulating dopamine release and gating windows of dopamine-facilitated plasticity. The authors hypothesized that ventral striatal CINs (vsCINs) might therefore bias reward learning during acquisition or promote impulse control during stable performance.
Using chemogenetic activation and inhibition of vsCINs in Sprague Dawley rats, the study found that manipulating these neurons once behavior was stable altered motor impulsivity—activation increased premature responses and inhibition decreased them—in both sexes, without changing choice patterns. In contrast, when vsCINs were manipulated during task acquisition, they did not affect motor impulsivity but instead shifted risky choice: activation reduced risky choices in males, whereas inhibition increased risky choices in females.
These results support the idea that acetylcholine–dopamine interactions in the ventral striatum contribute differently to learning versus performance, and they provide a framework for future experiments to test mechanisms that could underlie the observed sex differences.