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Abstract #0124

Ketamine Decreases Resting State Functional Connectivity between Networks Via the Dorsal Nexus: Implications for Major Depression

SUMMA25Milan Scheidegger1, 2, Martin Walter3, Mick Lehmann2, Coraline Metzger3, Simone Grimm2, 4, Heinz Boeker2, Peter Boesiger1, Erich Seifritz2, Anke Henning1

1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 2Clinic of Affective Disorders and General Psychiatry, University Hospital of Psychiatry Zurich, Zurich, Switzerland; 3Department of Psychiatry, Otto-von-Guericke University, Magdeburg, Germany; 4Cluster Languages of Emotion, Freie Universitt Berlin, Berlin, Germany

Using resting state fMRI (rsfMRI), the dorsal nexus (DN) was recently identified as a dorsomedial prefrontal cortex region showing increased depression-associated fMRI connectivity with portions of the cognitive control (CCN), the default mode (DMN), and the affective (AN) network. In this double-blind, randomized, placebo-controlled, crossover study we report decreased connectivity of the sgACC (AN) and PCC (DMN) via the DN 24 hours following the administration of an antidepressant dose of ketamine. We conclude that reducing the hyperconnectivity via the DN may play a critical role in reducing depressive symptomatology and thus represent a systems level mechanism of antidepressant treatment response.