Dual-engram architecture within a single striatal cell type distinctly controls alcohol relapse and extinction

Area of Science:

• Neuroscience
• Addiction Research
• Cellular Biology

Background:

• Relapse is a significant challenge in addiction treatment, often driven by persistent drug-associated memories.
• Extinction training can reduce relapse by forming competing memories, but the neural storage mechanisms remain unclear.

Purpose of the Study:

• To investigate the neural substrates of opposing alcohol-associated memories and extinction memories within the striatum.
• To identify the specific neuronal ensembles and synaptic mechanisms underlying addiction relapse and suppression.

Main Methods:

• Utilized mouse models to study operant alcohol learning and extinction.
• Employed techniques to identify and characterize distinct neuronal ensembles (engrams) in direct-pathway medium spiny neurons (dMSNs).
• Examined synaptic plasticity in corticostriatal pathways associated with memory formation.

Main Results:

• Identified two distinct engram ensembles within dMSNs: one broadly distributed encoding relapse-promoting memories, and another striosome-enriched encoding extinction memories.
• Demonstrated that relapse-promoting memories involve persistently strengthened corticostriatal synapses.
• Showed that mimicking this synaptic strengthening can induce relapse-like behaviors.

Conclusions:

• Established a dual-engram architecture within dorsostriatal dMSNs that governs the balance between addiction relapse and extinction.
• Highlighted the critical role of specific synaptic changes in corticostriatal pathways in maintaining relapse-promoting memories.