Stress-impaired reward pathway promotes distinct feeding behavior patterns

Area of Science:

• Neuroscience
• Behavioral Science
• Psychiatry

Background:

• Neuropsychiatric disorders and environmental factors significantly influence dietary behaviors.
• The mesolimbic dopamine system plays a crucial role in reward and motivation, impacting feeding patterns.
• Stress-induced alterations in feeding behavior are a growing area of research.

Purpose of the Study:

• To investigate the impact of multiple stressors on feeding behavior patterns in mice.
• To explore the role of the mesolimbic dopamine system in stress-induced feeding abnormalities.
• To identify potential biomarkers for psychosocial and physical stress.

Main Methods:

• Mice were subjected to a combination of stressors: social isolation, intermittent high-fat diet, and physical restraint.
• Feeding behavior, specifically bait approach, was analyzed.
• Dopamine release in the nucleus accumbens (NAcc) shell was measured.
• Pharmacological interventions were used to normalize dopamine levels and inhibit dopaminergic activity.

Main Results:

• Stressed mice exhibited a 'fixated feeding' pattern, characterized by a deviated bait approach.
• All tested stressors altered dopamine release in the NAcc shell.
• Normalization of dopamine levels reversed the observed feeding defects.
• Inhibition of dopaminergic activity in the ventral tegmental area mimicked these feeding aberrations.

Conclusions:

• Alterations in feeding behavior patterns, specifically fixated feeding, are linked to perturbations in the stress-associated mesolimbic dopamine pathway.
• These feeding deviations are sensitive biomarkers of psychosocial and physical stress, independent of changes in consumption or metabolic factors.
• The findings highlight the connection between stress, reward system function, and observable feeding behaviors.