Willed action and the prefrontal cortex in man: a study with PET

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Brain Imaging

Background:

• Understanding the neural basis of voluntary action is key to cognitive neuroscience.
• Distinguishing between automatic and deliberate actions helps elucidate executive functions.

Purpose of the Study:

• To investigate the neural correlates of willed actions versus routine actions using brain imaging.
• To identify brain regions associated with decision-making and voluntary control.

Main Methods:

• Positron emission tomography (PET) was employed to measure changes in cerebral blood flow.
• Participants performed tasks involving routine and willed actions in different response modalities (speaking, finger lifting).

Main Results:

• Willed actions, requiring deliberate choice, showed increased cerebral blood flow in the dorsolateral prefrontal cortex (Brodmann area 46).
• Routine actions, where responses were stimulus-determined, did not show the same prefrontal activation pattern.
• Decreased blood flow was observed during willed actions, with locations varying based on the response modality.

Conclusions:

• The dorsolateral prefrontal cortex is critically involved in the initiation and execution of willed actions.
• Cerebral blood flow patterns differ significantly between voluntary decision-making and stimulus-response behaviors.
• Modality-specific effects highlight the complex neural networks underlying different types of voluntary actions.