Volition to action--an event-related fMRI study.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Brain Imaging

Background:

• The anterior cingulate cortex (ACC) is increasingly recognized as a crucial interface between limbic and neocortical functions.
• ACC activation is hypothesized to reflect the intentional effort or volition exerted by an individual during a task.
• Previous electrophysiological studies indicated early ACC activation during choice reaction tasks, correlating negatively with reaction time.

Purpose of the Study:

• To precisely localize the early midline ACC activation observed in previous electrophysiological studies.
• To further investigate the relationship between ACC activation and task engagement during a choice reaction task using fMRI.

Main Methods:

• An event-related functional Magnetic Resonance Imaging (fMRI) study was conducted.
• Six healthy volunteers performed a visual choice reaction task involving stimuli presented in either the left or right visual hemifield.
• Blood-oxygen-level-dependent (BOLD) signals were measured during stimulus presentation and motor response.

Main Results:

• A bilateral BOLD signal maximum was identified in the supplementary motor area, adjacent to the dorsal ACC.
• The extent of ACC activation showed a significant negative correlation with reaction time.
• These findings align with previous electrophysiological data suggesting a role for ACC in effort-related processing.

Conclusions:

• Early activation in the dorsal ACC during a choice reaction task is accurately localized using fMRI.
• The degree of ACC activation is a reliable indicator of a subject's intentional effort and engagement in a task.
• This study provides robust evidence supporting the ACC's role in mediating volition and task performance.