Excessive alcohol consumption compromises essential brain functions, such as cognitive flexibility, disrupting our abilities to learn and adapt, researchers say.
- Researchers have discovered that alcohol abuse disrupts the “burst-pause” firing patterns of cholinergic interneurons (CINs) in the striatum, which regulate the release of acetylcholine, a neurotransmitter crucial for adaptation.
- Altering these patterns compromises key processes like reversal learning, essential for adapting to new situations.
- This research opens avenues for restoring these dynamics and developing therapies targeting cognitive disorders linked to alcohol abuse.
Alcohol use disorders affect approximately 400 million people worldwide, leading to serious illnesses such as cancer, cardiovascular disease, liver disease and stroke. In addition to these physical consequences, alcohol dependence profoundly disrupts essential cognitive functions, including cognitive flexibility, which is essential for learning, memorizing and adapting.
In a study published in the journal Science Advancesresearchers from Texas A&M College of Medicine, in the United States, recently shed light on the impact of alcohol on neuronal signaling pathways, focusing on cholinergic interneurons (CINs) in the striatum, the heart of the reward system.
CINs, guardians of the reward system
Cholinergic interneurons regulate the release of acetylcholine, a key neurotransmitter. They play a crucial role in filtering stimuli that activate dopamine neurons, the engine of the reward system. According to the study, CINs act as gatekeepers, modulating dopaminergic responses to stimuli.
In animal models exposed to alcohol, scientists observed a significant alteration of the “burst-pause” pattern (burst-pause) CINs. Normally, this pattern involves a rapid discharge followed by a pause, an essential element for learning and adaptation. However, chronic exposure to alcohol reduces and weakens these breaks, compromising key processes such as reversal learning (reversal learning).
Flipped learning, a pillar of cognitive flexibility
Reversal learning involves unlearning behaviors when rules or circumstances change. This process relies heavily on acetylcholine signaling, which is disrupted by alcohol. By combining tools like optogenetics and fiber photometry, researchers explored the distinct roles of the “explosion” and “pause” phases. The “explosion” phase, increasing the release of acetylcholine, promotes the extinction of old behaviors. The “pause” phase, by reducing this release, is crucial for replacing these behaviors with new ones, a decisive element for adaptation.
This study offers promising prospects for targeting disorders linked to alcohol dependence. By restoring the “burst-pause” dynamics of CINs, it may be possible to improve cognitive flexibility and alleviate alcohol-induced disorders. “These mechanisms play a key role in behavioral adaptability”underline the researchers in a press release. They plan to continue their work to understand how these dynamics also influence other conditions, such as aging and neurodegenerative diseases.
