A role for the subthalamic nucleus in aversive learning

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Optogenetics

Background:

• The subthalamic nucleus (STN) is crucial for behavioral control, with its dysfunction linked to neurological disorders like Parkinson's disease.
• Deep brain stimulation (DBS) of the STN improves motor symptoms but can cause affective side effects like depression.
• The STN's proximity to the para-STN, involved in appetitive and aversive behaviors, raises questions about DBS-induced aversion.

Purpose of the Study:

• To investigate the causal role of the subthalamic nucleus (STN) in mediating aversion.
• To differentiate the aversive functions of the STN from the adjacent para-STN.
• To explore the neurobiological mechanisms underlying STN-mediated emotional affect.

Main Methods:

• Utilized optogenetics in mice to selectively stimulate STN and para-STN using specific promoters (Pitx2 for STN, Tac1 for para-STN).
• Assessed affective behaviors, including conditioned avoidance and disruption of reward-seeking (sugar self-administration).
• Performed electrophysiological recordings in pallidal neurons and stimulated STN terminals in the ventral pallidum.

Main Results:

• Both STN and para-STN stimulation induced acute aversion.
• Only STN stimulation-paired cues led to conditioned avoidance.
• STN stimulation selectively interrupted ongoing sugar self-administration, and STN terminal stimulation in the ventral pallidum replicated aversion.

Conclusions:

• The subthalamic nucleus (STN) is identified as a direct source of aversive learning and behavior.
• Findings contribute to understanding the neurobiological underpinnings of emotional affect and STN's role in mood disorders.
• Differentiates the specific contribution of STN versus para-STN in aversion, informing DBS strategies.