Regional Striatal Cholinergic Involvement in Human Behavioral Flexibility.

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neuroimaging

Background:

• The striatal cholinergic system is implicated in behavioral flexibility in animal models.
• Noninvasive human studies of this system were previously limited by technique availability.
• Previous research demonstrated changes in dorsal striatal choline during human reversal learning.

Purpose of the Study:

• To investigate the association between regional average striatal choline concentration and reversal learning performance in humans.
• To explore the role of the dorsal striatal cholinergic system in human behavioral flexibility.

Main Methods:

• Proton magnetic resonance spectroscopy (MRS) was used to measure choline levels at rest in the dorsal and ventral striatum.
• Twenty-two participants completed a probabilistic learning task with a reversal component.
• A reinforcement learning model was employed to analyze task performance, differentiating positive and negative prediction errors.

Main Results:

• Average choline levels in the dorsal striatum, but not the ventral striatum, were significantly associated with reversal learning performance.
• Lower dorsal striatal choline concentrations correlated with a higher number of perseverative trials during reversal.
• Dorsal striatal choline levels explained interindividual differences in perseveration beyond learning from negative prediction errors.

Conclusions:

• Findings support the role of the dorsal striatal cholinergic system in human behavioral flexibility, consistent with animal studies.
• Measuring choline with MRS offers a noninvasive method for studying human cholinergic neurochemistry.
• This research bridges the gap between animal and human findings and has implications for understanding cholinergic disorders.