Anticipation causes increased blood flow to the anterior cingulate cortex

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Medical Imaging

Background:

• Positron Emission Tomography (PET) studies often show increased cerebral blood flow (CBF) in the anterior cingulate cortex (ACC) during cognitively demanding tasks.
• The precise role of task-related processing versus preparatory states in this ACC activation remains unclear.

Purpose of the Study:

• To investigate whether anticipation and preparation for a cognitive task, or the task processing itself, primarily drives increased CBF in the ACC.
• To differentiate the neural correlates of task engagement versus task anticipation.

Main Methods:

• A PET study utilizing the bolus H2(15)O intravenous injection technique was conducted on 10 healthy male subjects.
• Subjects underwent scanning during passive viewing, abstract pattern recognition, picture naming, semantic judgment, and crucially, during anticipatory states preceding these tasks.

Main Results:

• All three cognitive tasks demonstrated significantly increased CBF in the ACC compared to baseline.
• A comparable significant increase in ACC blood flow was observed during anticipatory states before each task.
• When anticipatory scans served as the baseline, the subsequent cognitive task did not yield a significant CBF increase in the ACC.

Conclusions:

• The findings suggest that the increased ACC blood flow observed in many PET studies of cognitive tasks may be primarily driven by the processes of receiving instructions, preparation, and anticipation.
• Task-related processing itself might contribute less significantly to ACC activation than previously assumed.
• This highlights the importance of considering preparatory neural activity in the interpretation of neuroimaging studies of cognition.