Affiliation:
1. Ahmanson‐Lovelace Brain Mapping Center, Department of Neurology University of California Los Angeles Los Angeles California USA
2. Department of Radiology Northwestern University Chicago Illinois USA
3. Division of Neuropsychiatry and Neuromodulation Massachusetts General Hospital and Harvard Medical School Boston Massachusetts USA
4. Department of Psychiatry and Biobehavioral Sciences University of California Los Angeles Los Angeles California USA
Abstract
AbstractIntroductionMajor depressive disorder (MDD) is associated with dysfunctional reward processing, which involves functional circuitry of the habenula (Hb) and nucleus accumbens (NAc). Since ketamine elicits rapid antidepressant and antianhedonic effects in MDD, this study sought to investigate how serial ketamine infusion (SKI) treatment modulates static and dynamic functional connectivity (FC) in Hb and NAc functional networks.MethodsMDD participants (n = 58, mean age = 40.7 years, female = 28) received four ketamine infusions (0.5 mg/kg) 2−3 times weekly. Resting‐state functional magnetic resonance imaging (fMRI) scans and clinical assessments were collected at baseline and 24 h post‐SKI. Static FC (sFC) and dynamic FC variability (dFCv) were calculated from left and right Hb and NAc seeds to all other brain regions. Changes in FC pre‐to‐post SKI, and correlations with changes with mood and anhedonia were examined. Comparisons of FC between patients and healthy controls (HC) at baseline (n = 55, mean age = 32.6, female = 31), and between HC assessed twice (n = 16) were conducted as follow‐up analyses.ResultsFollowing SKI, significant increases in left Hb‐bilateral visual cortex FC, decreases in left Hb‐left inferior parietal cortex FC, and decreases in left NAc‐right cerebellum FC occurred. Decreased dFCv between left Hb and right precuneus and visual cortex, and decreased dFCv between right NAc and right visual cortex both significantly correlated with improvements in mood ratings. Decreased FC between left Hb and bilateral visual/parietal cortices as well as increased FC between left NAc and right visual/parietal cortices both significantly correlated with improvements in anhedonia. No differences were observed between HC at baseline or over time.ConclusionSubanesthetic ketamine modulates functional pathways linking the Hb and NAc with visual, parietal, and cerebellar regions in MDD. Overlapping effects between Hb and NAc functional systems were associated with ketamine's therapeutic response.
Funder
National Institute of Mental Health