An eight-week mindfulness intervention did not reduce impulsivity on the go/no-go task or Barratt Impulsiveness Scale (BIS-11), nor produce changes in neural correlates such as frontostriatal gray matter, functional connectivity, or dopamine levels compared to active or wait-list control groups. Long-term meditators (LTMs) did not differ from meditation-naïve participants (MNPs) on the go/no-go task, but LTMs self-reported lower attentional impulsivity and higher motor and non-planning impulsivity on the BIS-11. LTMs had less striatal gray matter, greater cortico-striatal-thalamic functional connectivity, and lower spontaneous eye-blink rate than MNPs. Total lifetime practice hours did not significantly relate to impulsivity or neurobiological metrics, suggesting pre-existing differences may account for group differences.
Long-term meditators blink less frequently and show a different eyeblink pattern than meditation-naive participants, with high consistency over three time points. This pattern may reflect differences in striatal dopamine activity, as spontaneous eyeblink rate is a peripheral correlate of such activity. An 8-week mindfulness-based stress reduction course did not alter eyeblink rates compared to active or waitlist controls, and a full day of two different meditation types also had no effect. These results suggest either that individual differences in dopaminergic neurotransmission predispose people to meditation, or that long-term, but not short-term, practice induces stable changes in baseline striatal dopaminergic functioning.