Neural Oscillatory and Sympathetic Arousal Dynamics During Mindfulness Meditation: Characterizing Relaxed Alertness.

Mindfulness meditation is often characterized as a state of relaxed alertness, yet the neural and autonomic processes that define this state remain unclear. This study examined concurrent electroencephalographic (EEG) oscillations and skin conductance level (SCL) during brief breath-focused mindfulness meditation, with a focus on temporal dynamics. EEG and SCL were recorded during 2 min of eyes-closed rest and a 15 min mindfulness meditation, with analyses focused on 8 min of the silent self-guided period following instruction, divided into four consecutive 2 min segments. Planned contrasts compared eyes-closed rest with mindfulness meditation and examined changes across the meditation period, while sex-related variability was explored. Meditation was associated with greater theta (4-7.5 Hz) amplitude than rest. Exploratory analyses also indicated greater delta (1-3.5 Hz) amplitude during meditation and a progressive increase in delta across the meditation period. Alpha amplitude (8-13 Hz) showed no reliable state-related or temporal effects. SCL did not differ between rest and meditation overall, although an exploratory trend analysis indicated an initial decrease followed by a later increase during meditation. Global alpha amplitude was positively associated with SCL during meditation, after accounting for participant differences and changes across the meditation period. Exploratory sex analyses suggested a larger rest-to-meditation theta increase in males and greater beta and gamma amplitudes in females across states, although these findings should be considered preliminary. Together, these results suggest that mindfulness meditation is not simply characterized by reduced arousal, but instead involves dynamic patterns of neural activity and sympathetic arousal that are broadly consistent with relaxed alertness.