Changes in cerebral connectivity and brain tissue pulsations with the antidepressant response to an equimolar mixture of oxygen and nitrous oxide: an MRI and ultrasound study.
Molecular psychiatry September 1, 2023 Thomas Desmidt, Paul-Armand Dujardin, Frédéric Andersson et al.
A single one-hour session of a 50:50 nitrous oxide/oxygen mixture (EMONO) rapidly alters functional connectivity in the default mode network and increases brain tissue pulsations in depressed women who respond to the treatment. Among 20 women with treatment-resistant depression, 45% showed at least a 50% reduction in depression scores one week after exposure. Responders exhibited decreased connectivity between the subgenual anterior cingulate cortex and the precuneus, and a larger early increase in brain tissue pulsations, which may enhance drug delivery. Non-responders and healthy controls showed different connectivity changes. The findings suggest potential cerebral mechanisms and markers for antidepressant response to nitrous oxide.