Sign Tracking in an Enriched Environment: A Potential Ecologically Relevant Animal Model of Adaptive Behavior Change

Area of Science:

• Neuroscience
• Behavioral Science
• Addiction Research

Background:

• Sign tracking, a behavior directed at a conditioned stimulus (CS), is linked to compulsive drug use.
• Environmental enrichment is known to protect against addiction-prone phenotypes.
• Previous research assumed sign tracking is inflexible and habit-like.

Purpose of the Study:

• Investigate if compulsive-like sign tracking develops in environmentally enriched rats.
• Examine the influence of enrichment and stress on sign and goal tracking in adolescent vs. adult rats.
• Assess the ecological relevance of object conditioned stimuli in enriched environments.

Main Methods:

• Adolescent Sprague-Dawley rats were housed in enriched or standard conditions.
• Rats were trained to sign track a 5% ethanol bottle conditioned stimulus (CS) in their home environment.
• Acute isolation stress was applied to assess its impact on sign and goal tracking.

Main Results:

• Enriched adolescent rats exhibited higher sign tracking rates than standard-housed controls.
• Enriched adolescent rats showed less sign tracking than enriched adult rats.
• Stress differentially affected sign and goal tracking in adolescents and adults, with adults showing increased sign tracking and adolescents showing decreased goal tracking.

Conclusions:

• Compulsive-like sign tracking develops in enriched adolescent rats within their home environment.
• Sign tracking may be less inflexible than previously assumed.
• Enriched home environments with object CSs offer greater ecological validity for addiction research.