Ventral striatal astrocytes contribute to reinforcement learning.

Area of Science:

• Neuroscience
• Computational Neuroscience
• Cellular Neuroscience

Background:

• Astrocytes modulate neuronal function and synaptic plasticity via astrocytic calcium dynamics (ACD).
• The specific role of astrocytes in complex cognitive processes like reinforcement learning (RL) is not well understood.

Purpose of the Study:

• To investigate the contribution of astrocytes to reinforcement learning (RL) and decision-making.
• To examine how astrocytic calcium dynamics (ACD) in the striatum influence probabilistic decision-making tasks.

Main Methods:

• Mice were trained on a reinforcement learning (RL)-dependent probabilistic decision-making task.
• Astrocytic calcium dynamics (ACD) were attenuated in specific striatal regions.
• In vivo calcium imaging, ex vivo slice electrophysiology, and computational modeling were employed.

Main Results:

• Attenuation of ACD specifically in the ventral striatum (VS) increased decision noisiness and impaired reward-guided choice, primarily by reducing 'win-stay' behavior.
• VS ACD correlated with reward prediction errors (RPEs) and predicted trial-by-trial choice variability.
• Astrocytes regulate behavioral variability by influencing the excitatory-inhibitory balance and sharing RPE signals among striatal neurons.

Conclusions:

• Ventral striatum (VS) astrocytes play a crucial role in mediating decision noisiness within cortico-striatal circuits.
• Astrocytic calcium dynamics (ACD) are integral to reinforcement learning (RL) and reward-guided behavior.
• Astrocytes contribute to cognitive functions by regulating neuronal network states and information processing.