Secondary motor cortex tracks decision value during the learning of a non-instructed task

Area of Science:

• Neuroscience
• Cognitive Science
• Behavioral Science

Background:

• Optimal decision-making relies on frontal brain regions for adapting choices based on internal states, experience, and context.
• The secondary motor cortex (M2) is crucial for adaptive behaviors in expert rodents, encoding decision values for complex tasks.
• The M2's role in deterministic tasks during initial learning is not well understood.

Purpose of the Study:

• To investigate the role of the secondary motor cortex (M2) in adaptive choice during initial learning in a self-initiated deterministic task.
• To determine if M2 neurons encode decision values that predict action selection in a cue-free environment.
• To examine the impact of M2 inhibition on task performance and decision value updates.

Main Methods:

• Developed a self-initiated deterministic forepaw choice task for mice.
• Utilized in vivo microscopy and computational modeling to analyze neuronal activity in the M2.
• Employed optogenetic inhibition of the M2 to assess its causal role in behavior.

Main Results:

• Spontaneous decisions in the task follow a race model, revealing underlying decision values.
• M2 neurons in male mice exhibit persistent activity encoding decision values that predict action selection probabilities.
• Optogenetic inhibition of the M2 impaired reversal learning performance and altered decision value representations.

Conclusions:

• The secondary motor cortex (M2) utilizes decision values to adapt choices during initial learning in a deterministic, cue-free task.
• M2 activity encodes decision values that predict action selection and guide adaptive behavior.
• Decision value updates in the M2 are critical for rapid reversal learning.