The Effects of 8-Week Mindfulness-Based Stress Reduction Program on Cognitive Control: an EEG Study

Objectives: Mindfulness practice can enhance different aspects of attentional functions, such as the ability to sustain the attentional focus over time. However, it is still unclear whether this practice might indeed impact higher cognitive functions, such as control mechanisms that allow the appropriate and flexible allocation of attentional resources. In this longitudinal study, changes associated with a mindfulness-based stress reduction (MBSR) program were investigated, with a focus on proactive and reactive cognitive control mechanisms, namely, the ability to maintain task-relevant information and to prepare in advance the response, and the ability to promptly adjust overlearned behaviors in response to conflicting stimuli. Methods: Two groups of participants took part in the study: 26 participants who completed a formal MBSR training (mean age = 43 years, females = 21) and 23 participants who performed a control training (mean age = 47.2 years, females = 20). They were tested on a modified AX-continuous performance task (AX-CPT), before and after eight weeks of training. The electroencephalographic (EEG) signal was recorded during task execution, and amplitude modulations of event-related potentials (ERPs) associated with cues and probes were examined. Results: After the training, the MBSR group exhibited a significant reduction of errors on high conflicting trials. Concurrently, the Contingent Negative Variation (CNV), an ERP index of anticipatory processes elicited by task cues, became more pronounced in the post-training session in the MBSR group only. In addition, an attenuated probe-locked N2 and an increased P3a component emerged. Conclusions: Taken together, the behavioral and electrophysiological results suggest that the mindfulness practice enhanced the ability to implement both proactive and reactive cognitive control processes.