Slow Breathing Reduces Anxiety Behaviors in Mice Without Conscious Awareness

A study presented at the Embodied Minds Summit in Los Angeles on 3 May found that slow breathing reduces anxiety-like behaviors in mice even when the animals have no awareness of the intended effect. Jack Feldman, a neuroscientist at UCLA, presented results showing that mice trained to breathe more slowly froze less often in stressful situations and spent more time exploring open spaces compared with control mice.

The work builds on Feldman’s 1991 discovery that the pre-Bötzinger Complex in the brainstem acts as the master pacemaker for breathing rate in mammals.

Researchers used optogenetics to insert light-sensitive proteins into neurons in the pre-Bötzinger Complex that inhibit inhalation and lengthen exhalation. Pulses of light slowed the mice’s breathing rate by up to 70 percent during daily sessions over four weeks.

After training, the mice maintained slower breathing rates even between sessions. Three days after the final session, the animals underwent standard tests of anxiety-like behavior.

Andrea Zaccaro, a neuroscientist at the “G. d’Annunzio” University of Chieti-Pescara in Italy, said the results isolate a bottom-up physiological component of the breathing-emotion relationship. Zaccaro added that mindful attention to the breath could still amplify or stabilize the physiological effects of slower breathing.

627565, indicates that the calming effect of slow breathing does not require conscious belief in its benefits.