A single 96-hour infusion of ketamine, co-administered with clonidine, is well tolerated and produces a rapid and sustained antidepressant response in over 50% of adults with treatment-resistant depression. In an open-label study of 23 adults, depressive symptoms dropped markedly from an average MADRS score of 29 at baseline to 9 one day after infusion, and remained reduced at 2 weeks (13) and 8 weeks (15). Brain imaging showed that the infusion normalized overconnectivity in the limbic system and between the subgenual anterior cingulate cortex and the default mode network, with response-dependent and treatment-dependent connectivity changes.
A narrative review of 30 studies examined how exercise, mindful movement, and mindfulness training affect resting state functional connectivity (rsFC) in the brains of non-clinical adults. Most studies reported changes in rsFC within the default mode, executive control, and salience networks. However, the largest and most methodologically rigorous study found minimal associations between rsFC and either exercise or mindfulness. Given the inconsistent results, caution is warranted in interpreting changes in rsFC attributable to these interventions. Methodological consistency in fMRI acquisition, data preparation, and analytical approaches is crucial to improve reproducibility and allow for comparison and aggregation.