Common and distinct neural substrates for approach- and avoidance-motivated actions

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Decision Neuroscience

Background:

• Human behavior is guided by motivations to approach rewards and avoid negative outcomes.
• The neural underpinnings of these opposing motivations and their integration into motor actions remain incompletely understood.

Purpose of the Study:

• To investigate the distinct and shared neural pathways for approach (reward) and avoidance (loss) motivations.
• To elucidate how these motivations are represented and integrated within the brain to influence motor output.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed in 29 healthy participants.
• A ready-set-go task was used, incorporating monetary gains (approach) and losses (avoidance).
• Analysis focused on prefrontal cortex, ventral midbrain (VM), and primary motor cortex activity, correlating with behavioral measures like grip force and reaction time (RT).

Main Results:

• Distinct prefrontal activations were observed for gain (ventromedial prefrontal cortex) and loss (dorsomedial prefrontal cortex) anticipation.
• The dorsolateral ventral midbrain (VM) showed activation for both motivations, while the ventromedial VM was selective for gains.
• Dorsolateral VM activity correlated with grip force, indicating its role in motivational signal transmission to motor circuits.

Conclusions:

• A hierarchical neural circuit for motivated action is proposed, with distinct cortical representations, subcortical convergence in the VM, and modulation of motor cortex activity.
• Opposing motivations utilize both distinct and shared neural pathways, integrated via subcortical-cortical interactions to shape motor output.
• These findings advance the understanding of motivation-motor interactions and have implications for disorders affecting motivated behavior.