Mindfulness meditation has been linked to reduced stress hormone levels, remodeling of white matter tracts around the brain’s anterior cingulate cortex (ACC), and reduced anxiety in previous studies.

Using optogenetic tools, researchers tested whether rhythmic stimulation or suppression of ACC activity at frequencies reminiscent of meditation training influences anxiety in mice.

Compared with mice that received no intervention and mice in which rhythmic ACC activity was suppressed, mice in which rhythmic ACC activity was induced in a month-long intervention over 20 sessions lasting 30 minutes each exhibited less anxiety, as indicated by their willingness to explore an illuminated environment in a well-established laboratory test of anxiety.

Further, reduced anxiety was associated largely with 1 Hz and 8 Hz stimulation, but not with 40 Hz stimulation. Rhythmic stimulation of the ACC appeared not to affect the animals’ spontaneous motor activity, cognitive ability, or memory in an experimental setup, suggesting that the observed effects of rhythmic stimulation might reflect its effect on anxiety.

Additional tests may help cement a link between rhythmic ACC stimulation and anxiety, but the study furnishes a potential animal model for the fine-grained analysis of the effects of some forms of meditation on the human brain, according to the authors.