Chronic Stress Prevents Cortico-Accumbens Cue Encoding and Alters Conditioned Approach.

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Stress and Motivation

Background:

• Chronic stress negatively impacts brain function, leading to hedonic and motivational deficits.
• The prefrontal cortex (PFC), particularly the prelimbic cortex-nucleus accumbens core (PL-NAcC) pathway, is crucial for motivated approach behavior.
• How stress alters the PL-NAcC pathway's role in associative learning and cue encoding remains unclear.

Purpose of the Study:

• To investigate the involvement of the PL-NAcC pathway in acquiring learned approach behaviors using Pavlovian autoshaping.
• To determine if chronic stress disrupts the encoding of approach-associated cues within the PL-NAcC pathway.
• To test the hypothesis that stress impairs both conditioned approach and cue encoding in this pathway.

Main Methods:

• Utilized an intersectional fiber photometry approach in male Sprague Dawley rats.
• Employed a Pavlovian autoshaping paradigm to assess learned approach behavior.
• Measured neural activity in the PL-NAcC pathway during cue-approach associations.

Main Results:

• Rapid acquisition of conditioned approach behavior correlated with cue-induced PL-NAcC pathway activity.
• Prior exposure to chronic stress significantly reduced cue-directed behavior.
• Stress impaired the neural activity in the PL-NAcC pathway associated with the conditioned cue.

Conclusions:

• Stress diminishes task-related activity in the PL-NAcC brain pathway, which regulates approach behavior.
• Stress disrupts reward processing by altering the incentive value of associated cues.
• Findings highlight the PL-NAcC pathway as a key mediator of stress-induced motivational deficits.