Conjoint specification of action by neocortex and striatum

Area of Science:

• Neuroscience
• Motor Control
• Computational Neuroscience

Background:

• The cortex and striatum are key forebrain structures for flexible, goal-directed actions.
• Traditional views assigned distinct roles: striatum for action initiation and motor cortex for movement parameter specification.
• Emerging evidence suggests the striatum may also contribute to movement specification, creating a need to reconcile these roles.

Purpose of the Study:

• To investigate the distinct and overlapping roles of the cortex and striatum in movement control.
• To reconcile conflicting models of cortical and striatal function in action selection and parameter specification.
• To develop quantitative models and experimental paradigms that can differentiate between competing hypotheses.

Main Methods:

• Development of quantitative computational models to predict neural activity patterns.
• Design of a novel reach-to-pull behavioral task in mice involving selection between similar actions (targets and forces).
• Simultaneous electrophysiological recordings from cortical and subcortical (striatal) areas during task performance.

Main Results:

• Comparing neural activity across similar actions, rather than distinct ones, yielded strongly distinguishing predictions.
• The novel reach-to-pull task allowed mice to reliably select between similar but distinct movement parameters.
• Simultaneous recordings provided data uniquely consistent with a model of joint cortical and striatal specification of movement parameters.

Conclusions:

• The cortex and striatum do not operate in strict segregation but jointly specify continuous parameters for movement execution.
• Neural activity analysis across similar actions is crucial for uncovering the nuanced roles of brain regions in motor control.
• This study advances our understanding of the neural basis of flexible, goal-directed behavior.