Direct Pathway Neurons in the Mouse Ventral Striatum Are Active During Goal-Directed Action but Not Reward...

Area of Science:

• Neuroscience
• Behavioral Science
• Computational Neuroscience

Background:

• Learning involves acquisition and mastery phases, with dopamine signaling facilitating the transition.
• Dopamine neurons in the ventral striatum (VS) provide a teaching signal for learning.
• The precise role of VS neurons in encoding decision-making during learning is not fully understood.

Purpose of the Study:

• To investigate the role of VS direct pathway spiny projection neurons (dSPNs) in decision-making during operant conditioning.
• To understand how dSPNs contribute to learned action-outcome associations.

Main Methods:

• An operant conditioning paradigm was developed using open-source microcontrollers to train mice through three learning phases.
• Mice were trained using classical conditioning, operant conditioning, and a combined phase requiring lever presses during a conditioned stimulus (CS) for reward.
• Calcium imaging recorded activity from VS dSPNs throughout the training phases.

Main Results:

• VS dSPNs showed specific engagement during decision-making to perform reward-seeking actions in response to a CS.
• dSPN activity was largely absent during actions performed outside the CS.
• This suggests a specialized role for dSPNs in initiating learned, cue-driven behaviors.

Conclusions:

• Direct pathway neurons in the VS are integral to decision-making processes in learned action-outcome associations.
• These findings highlight a specialized function of VS dSPNs in initiating operant behaviors.
• The study provides insights into the neural mechanisms underlying motivated decision-making and skill automation.