Posterior cingulate cortex/precuneus blood oxygen-level dependent signal changes during the repetition of an attention task in meditators and nonmeditators

Abstract

Background and purpose: Among several cognitive advantages, meditation is thought to enhance practitioners' capacity for sustained attention. In the present study, we explored this question by testing meditation practitioners (meditators) and nonpractitioners (nonmeditators) on a task that requires sustained attention, the Stroop Word-Color Task (SWCT), while using functional MRI.

Participants and methods: Participants were all right-handed and included 23 regular meditators as well as 17 nonmeditators. Participants viewed color words (i.e. 'red,' 'blue,' or 'green') presented one at a time on the screen that were written in either the same color (congruent condition) or a different color (incongruent condition) and were asked to indicate the color of the print. Participants also viewed noncolor words written in unrelated colors (neutral condition). Both groups completed the same two acquisition runs.

Results: Although both meditators and nonmeditators gave faster responses on run 2 than run 1 for both the neutral and incongruent trials, nonmeditators showed decreased activation and meditators showed increased activation in precuneus/posterior cingulate cortex. These regions were previously shown to be activated in the SWCT and belong to default mode network as well as to cognitive control network.

Conclusion: Attention to repetitive stimuli during two equal runs of SWCT is mediated by the precuneus/posterior cingulate cortex, and mental training through meditation may influence the activity of these regions during such tasks.