Title:Effective Connectivity Between the Orbitofrontal Cortex and the Precuneus
Differentiates Major Psychiatric Disorders: Results from a Transdiagnostic
Spectral DCM Study
Volume: 22
Issue: 2
Author(s): Sevdalina Kandilarova, Drozdstoy Stoyanov*, Katrin Aryutova, Rossitsa Paunova, Mladen Mantarkov, Ivo Mitrev, Anna Todeva-Radneva and Karsten Specht
Affiliation:
- Department of Psychiatry and Medical Psychology, Medical University-Plovdiv, Plovdiv, Bulgaria
- Division of Translational
Neuroscience, Research Institute at Medical University-Plovdiv, Plovdiv, Bulgaria
Keywords:
Effective connectivity, transdiagnostic, schizophrenia, bipolar disorder, major depression, resting state MRI, spectral Dynamic Causal Modeling, precuneus, orbitofrontal cortex.
Abstract:
Background & Objective: We have previously identified aberrant connectivity of the
left precuneus, ventrolateral prefrontal cortex, anterior cingulate cortex, and anterior insula in patients
with either a paranoid (schizophrenia), or a depressive syndrome (both unipolar and bipolar).
In the current study, we attempted to replicate and expand these findings by including a healthy
control sample and separating the patients in a depressive episode into two groups: unipolar and
bipolar depression. We hypothesized that the connections between those major nodes of the resting
state networks would demonstrate different patterns in the three patient groups compared to the
healthy subjects.
Methods: Resting-state functional MRI was performed on a sample of 101 participants, of which
26 patients with schizophrenia (current psychotic episodes), 24 subjects with Bipolar Disorder (BD),
33 with Major Depressive Disorder (MDD) (both BD and MDD patients were in a current depressive
episode), and 21 healthy controls. Spectral Dynamic Causal Modeling was used to calculate
the coupling values between eight regions of interest, including the anterior precuneus (PRC),
anterior hippocampus, anterior insula, angular gyrus, lateral Orbitofrontal Cortex (OFC), middle
frontal gyrus, planum temporale, and anterior thalamus.
Results & Conclusion: We identified disturbed effective connectivity from the left lateral orbitofrontal
cortex to the left anterior precuneus that differed significantly between unipolar depression,
where the influence was inhibitory, and bipolar depression, where the effect was excitatory. A
logistic regression analysis correctly classified 75% of patients with unipolar and bipolar depression
based solely on the coupling values of this connection. In addition, patients with schizophrenia
demonstrated negative effective connectivity from the anterior PRC to the lateral OFC, which
distinguished them from healthy controls and patients with major depression. Future studies with
unmedicated patients will be needed to establish the replicability of our findings.
