Related Experiment Video
Updated: Jun 10, 2026
12:09
Studying Food Reward and Motivation in Humans
Published on: March 19, 2014
External incentives and internal states guide goal-directed behavior via the differential recruitment of the nucleus
J M Moscarello1, O Ben-Shahar, A Ettenberg
1Behavioral Pharmacology Laboratory, Department of Psychology, University of California, Santa Barbara, CA 93106-9660, USA.
Neuroscience
|July 20, 2010
Summary
Internal hunger states influence goal-directed behavior. The nucleus accumbens (NAcc) and medial prefrontal cortex (mPFC) play distinct roles in food-seeking, with NAcc crucial for motivation and mPFC important when food is scarce.
Area of Science:
- Neuroscience
- Behavioral Science
- Dopamine System Research
Background:
- Goal-directed behaviors are influenced by both internal physiological states (e.g., hunger) and external environmental cues (e.g., food).
- The mesocorticolimbic dopamine (DA) system is well-studied for its role in incentive-driven behavior, but its modulation by physiological states remains less understood.
- Understanding these interactions is crucial for comprehending motivated behaviors and potential dysregulations in conditions like addiction or eating disorders.
Purpose of the Study:
- To investigate the differential roles of the medial prefrontal cortex (mPFC) and nucleus accumbens (NAcc) in food-reinforced operant behavior.
- To examine how varying degrees of food deprivation (0, 12, and 36 hours) affect the function of the mPFC and NAcc in motivated behavior.
- To determine the impact of dopamine receptor blockade and temporary inactivation within the mPFC and NAcc on behavior under different deprivation states.
Main Methods:
- Rats were subjected to different durations of food deprivation (0, 12, 36 hours).
- Operant lever-press behavior was reinforced using fixed ratio 1 (FR1) and progressive ratio (PR) schedules.
- Temporary inactivation or dopamine receptor blockade was applied to the prelimbic mPFC or NAcc core to assess behavioral changes.
Main Results:
- Food deprivation increased PR breakpoints and lever-pressing on the FR1 schedule, indicating heightened motivation.
- NAcc inactivation or DA blockade reduced PR breakpoints irrespective of food deprivation, highlighting its general role in motivation.
- mPFC inactivation or DA blockade selectively reduced PR breakpoints in food-deprived rats, suggesting its specific role in state-dependent motivation.
Conclusions:
- The NAcc is critical for maintaining motivation when the cost of obtaining a reward increases, regardless of the animal's internal state.
- The mPFC becomes particularly important for regulating food-seeking behavior when animals are food-deprived and face sparser reinforcement.
- These findings reveal distinct contributions of the NAcc and mPFC within the dopamine system, differentially recruited based on reward value and physiological need.
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