Inactivation of the Prelimbic Cortex Attenuates Context-Dependent Operant Responding

Area of Science:

• Neuroscience
• Behavioral Science
• Cognitive Psychology

Background:

• Operant responding in rats models human voluntary behavior, crucial for studying maladaptive behaviors like overeating and drug relapse.
• Behavioral renewal, where extinguished behavior recovers in a different context, highlights the impact of environmental cues on behavior.
• The prelimbic (PL) region of the medial prefrontal cortex is implicated in context-dependent memory and behavior modification.

Purpose of the Study:

• To test the hypothesis that the PL is critical for context-dependent responding acquired during conditioning.
• To investigate the specific role of PL inactivation in ABA and ABC renewal paradigms.
• To determine if PL inactivation broadly affects renewal or specifically impacts context-dependent recovery of extinguished behavior.

Main Methods:

• Rats learned a lever-pressing response for sucrose-pellet rewards.
• Inactivation of the PL was achieved using baclofen/muscimol (B/M) infusions during behavioral testing.
• ABA and ABC renewal paradigms were employed, involving extinction and testing in various contexts (A, B, C, D) with and without PL inactivation.

Main Results:

• PL inactivation attenuated ABA renewal by reducing responding specifically in the original acquisition context (A).
• PL inactivation did not affect responding when animals were switched to a novel context (B) after acquisition.
• PL inactivation did not affect ACD renewal, indicating its effect is specific to the ABA renewal paradigm and not a general impairment of renewal.

Conclusions:

• The prelimbic cortex (PL) plays a specific role in ABA renewal, particularly in maintaining context-dependent associations with the original conditioning environment.
• PL inactivation does not broadly attenuate renewal but rather selectively impairs responding in the context where the behavior was initially learned.
• These findings refine our understanding of the PL's function in context-dependent memory and suggest targeted therapeutic approaches for behavioral relapse.