A Genetically Defined Compartmentalized Striatal Direct Pathway for Negative Reinforcement.

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Molecular Neuroscience

Background:

• The striosome, a subcompartment of the dorsal striatum, is linked to reinforcement learning and motivation.
• The precise contribution of striosomal neurons to these functions is not well understood.

Purpose of the Study:

• To investigate the role of a specific striosomal neuronal population expressing Teashirt family zinc finger 1 (Tshz1) in behavior.
• To elucidate the function of Tshz1-expressing striosomal neurons within the direct pathway of the basal ganglia.

Main Methods:

• Genetic identification and manipulation of Tshz1-expressing striosomal neurons in mice.
• Electrophysiological recordings to analyze neuronal responses to punishment and reward.
• Behavioral assays to assess learning, motivation, and movement in response to neuronal activation or inhibition.

Main Results:

• Tshz1-expressing striosomal neurons belong to the direct pathway and drive negative reinforcement and aversive learning.
• Activation of these neurons induces aversion and movement suppression, distinct from conventional direct pathway neurons.
• These neurons preferentially respond to punishment, signaling anticipation of punishment or avoidance motivation.
• Inhibition of Tshz1 neurons impairs punishment-based learning but not reward learning or general movement.

Conclusions:

• Striosomal Tshz1 neurons play a critical role in behaviors reinforced by punishment.
• These findings uncover novel functions of direct pathway neurons that extend beyond classical models of reinforcement learning.