Parvalbumin interneurons gate and shape striatal sequences

Area of Science:

• Neuroscience
• Behavioral Science

Background:

• Loss of parvalbumin-expressing interneurons (PV+) in the striatum is linked to impulsive behaviors.
• The precise role of these interneurons in striatal information processing and action control remains unclear.

Purpose of the Study:

• To investigate the function of PV+ interneurons in the sensorimotor striatum during action waiting and execution.
• To elucidate the role of PV+ interneurons in regulating impulsive and controlled behaviors.

Main Methods:

• Compared neural spiking activity of five identified neuron types in unrestrained rats during a cued-action task.
• Utilized optogenetic suppression of PV+ interneurons at different task phases (waiting vs. action initiation).

Main Results:

• PV+ interneurons selectively increased firing during the waiting period, and their suppression led to premature movements, indicating a role in action restraint.
• Suppression of PV+ interneurons after the cueing resulted in delayed action initiation and execution.
• Distinct, rapid striatal firing sequences involving spiny projection neurons (SPNs) and PV+ interneurons were observed during actions, with PV+ inhibiting SPNs.

Conclusions:

• PV+ interneurons are critical for both restraining premature actions and enabling timely action initiation and execution.
• These interneurons precisely sculpt striatal output through synchronized firing and inhibition of SPNs, ensuring fluid and appropriately timed motor behavior.