Modulation of Event-related Potentials of Visual Discrimination by Meditation Training and Sustained Attention.

Improvements in perceptual discrimination from intensive meditation training can alter brain signals related to attention and perception, but only when the task difficulty is fixed rather than adjusted to match the person's improving ability. In two three-month meditation retreats, participants performed a continuous visual task while brain activity was recorded. When the target difficulty was held constant, training reduced declines in early sensory processing and shifted the timing of those brain signals. Changes in later processing stages correlated with better perceptual thresholds. No such brain changes occurred when task difficulty was increased to keep pace with participants' improving skill. The findings show that directed mental training can modify electrophysiological markers of attention and perception, depending on how task demands relate to the individual's capacity.

Study at a glance

Abstract

The ability to discriminate among goal-relevant stimuli tends to diminish when detections must be made continuously over time. Previously, we reported that intensive training in shamatha (focused-attention) meditation can improve perceptual discrimination of difficult-to-detect visual stimuli [MacLean, K. A., Ferrer, E., Aichele, S. R., Bridwell, D. A., Zanesco, A. P., Jacobs, T. L., et al. Intensive meditation training improves perceptual discrimination and sustained attention. Psychological Science, 21, 829-839, 2010]. Here we extend these findings to examine how discrimination difficulty and meditation training interact to modulate event-related potentials of attention and perceptual processing during vigilance. Training and wait-list participants completed a continuous performance task at the beginning, middle, and end of two 3-month meditation interventions. In the first intervention (Retreat 1), the continuous performance task target was adjusted across assessments to match training-related changes in participants' perceptual capacity. In the second intervention (Retreat 2), the target was held constant across training, irrespective of changes in discrimination capacity. No training effects were observed in Retreat 1, whereas Retreat 2 was associated with changes in the onset of early sensory signals and an attenuation of within-task decrements at early latencies. In addition, changes at later stimulus processing stages were directly correlated with improvements in perceptual threshold across the second intervention. Overall, these findings demonstrate that improvements in perceptual discrimination can modulate electrophysiological markers of perceptual processing and attentional control during sustained attention, but likely only under conditions where an individual's discrimination capacity is allowed to exceed the demand imposed by the difficulty of a visual target. These results contribute to basic understanding of the dependence of perceptual processing and attentional control to contextual demands and their susceptibility to directed mental training.