Effects of meditation practice on spontaneous eyeblink rate

Summary

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.

Study at a glance

Abstract

A rapidly growing body of research suggests that meditation can change brain and cognitive functioning. Yet little is known about the neurochemical mechanisms underlying meditation-related changes in cognition. Here, we investigated the effects of meditation on spontaneous eyeblink rates (sEBR), a noninvasive peripheral correlate of striatal dopamine activity. Previous studies have shown a relationship between sEBR and cognitive functions such as mind wandering, cognitive flexibility, and attention-functions that are also affected by meditation. We therefore expected that long-term meditation practice would alter eyeblink activity. To test this, we recorded baseline sEBR and intereyeblink intervals (IEBI) in long-term meditators (LTM) and meditation-naive participants (MNP). We found that LTM not only blinked less frequently, but also showed a different eyeblink pattern than MNP. This pattern had good to high degree of consistency over three time points. Moreover, we examined the effects of an 8-week course of mindfulness-based stress reduction on sEBR and IEBI, compared to an active control group and a waitlist control group. No effect of short-term meditation practice was found. Finally, we investigated whether different types of meditation differentially alter eyeblink activity by measuring sEBR and IEBI after a full day of two kinds of meditation practices in the LTM. No effect of meditation type was found. Taken together, these findings may suggest either that individual difference in dopaminergic neurotransmission is a self-selection factor for meditation practice, or that long-term, but not short-term meditation practice induces stable changes in baseline striatal dopaminergic functioning.