Neural correlates of visuomotor associations. Spatial rules compared with arbitrary rules

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Motor Control

Background:

• Visuomotor transformations are crucial for interacting with the environment.
• Different tasks may engage distinct neural pathways for processing visual information and guiding motor responses.

Purpose of the Study:

• To investigate whether visual information influences the motor system through separate, task-dependent neural pathways.
• To contrast the neural mechanisms underlying spatially guided movements versus action selection based on arbitrary associations.

Main Methods:

• Positron emission tomography (PET) was employed to measure human brain activity.
• Participants performed two tasks: one involving spatially congruent grasping, the other involving arbitrary hand movements linked to visual stimuli.
• The study focused on preparatory brain activity preceding motor execution.

Main Results:

• Action selection based on associative rules specifically activated ventral prefrontal, striatal, and dorsal precentral areas.
• Spatially congruent grasping movements showed differential activation in ventral precentral and parietal regions.
• Distinct neural circuits were implicated in 'how' an action is performed versus 'which' action is selected.

Conclusions:

• Visual information processing for action execution appears to involve the dorsal visual system.
• Fronto-striatal loops are critical for selecting specific actions within a given context.
• The findings support a dual-pathway model for visuomotor transformations in the human brain.