Striatal modulation supports context-specific reinforcement and not action selection

Area of Science:

• Neuroscience
• Behavioral Science
• Computational Neuroscience

Background:

• Two models, action selection and reinforcement learning, explain basal ganglia functions.
• Previous studies used prolonged stimulation, neglecting the dynamic, brief neural activity patterns.

Purpose of the Study:

• To investigate how specific striatal subpopulations influence mouse behavior.
• To differentiate between action selection and reinforcement learning models by examining transient, context-specific striatal activity.

Main Methods:

• Transiently increased striatal activity in mice upon detecting locomotor arrest or turns.
• Stimulated direct and indirect pathways of the striatum selectively.
• Observed behavioral responses, including locomotion, arrest, and turning.

Main Results:

• Direct pathway stimulation unexpectedly increased locomotor arrest and leftward turns, irrespective of stimulation side.
• Indirect pathway stimulation produced opposite behavioral effects.
• Striatal activity modulated behavior independently of action type.

Conclusions:

• The striatum shapes behavioral dynamics by modulating action tendencies rather than selecting specific actions.
• Findings challenge existing action selection models and propose a new mechanism for behavioral control by the basal ganglia.