Anomalous single‐subject based morphological cortical networks in drug‐naive, first‐episode major depressive disorder

Abstract

Major depressive disorder (MDD) has been associated with disruptions in the topological organization of brain morphological networks in group-level data. Such disruptions have not yet been identified in single-patients, which is needed to show relations with symptom severity and to evaluate their potential as biomarkers for illness. To address this issue, we conducted a cross-sectional structural brain network study of 33 treatment-naive, first-episode MDD patients and 33 age-, gender-, and education-matched healthy controls (HCs). Weighted graph-theory based network models were used to characterize the topological organization of brain networks between the two groups. Compared with HCs, MDD patients exhibited lower normalized global efficiency and higher modularity in their whole-brain morphological networks, suggesting impaired integration and increased segregation of morphological brain networks in the patients. Locally, MDD patients exhibited lower efficiency in anatomic organization for transferring information predominantly in default-mode regions including the hippocampus, parahippocampal gyrus, precuneus and superior parietal lobule, and higher efficiency in the insula, calcarine and posterior cingulate cortex, and in the cerebellum. Morphological connectivity comparisons revealed two subnetworks that exhibited higher connectivity strength in MDD mainly involving neocortex-striatum-thalamus-cerebellum and thalamo-hippocampal circuitry. MDD-related alterations correlated with symptom severity and differentiated individuals with MDD from HCs with a sensitivity of 87.9% and specificity of 81.8%. Our findings indicate that single subject grey matter morphological networks are often disrupted in clinically relevant ways in treatment-naive, first episode MDD patients. Circuit-specific changes in brain anatomic network organization suggest alterations in the efficiency of information transfer within particular brain networks in MDD. Hum Brain Mapp 38:2482-2494, 2017. © 2017 Wiley Periodicals, Inc.

Alternations of White Matter Structural Networks in First Episode Untreated Major Depressive Disorder with Short Duration

“…The second major finding in the present study was a significantly decreased subnetwork existed in MDD patients, including bilateral OFC, left thalamus, postcentral gyrus, and hippocampus. Although our finding was consistent with most previous structural network studies showing the decreased subnetworks in MDD patients, several previous studies still reported increased connections in first-episode, medication-naive MDD patients ( 30 , 55 ). The inconsistent findings may be due to the sample heterogeneity and/or using of different network node and edge definitions, illness durations.…”

Abnormal Global Functional Connectivity Patterns in Medication-Free Major Depressive Disorder

“…Brain structural changes, including gray matter volume of insula, amygdala, hippocampus, frontal and temporal cortex ( Bora et al, 2012 ; Wang et al, 2017b ), and surface morphological properties of hippocampus and amygdala have been widely reported in MDD patients ( Chen et al, 2016 ). In addition, altered structural covariance between angular gyrus and amygdala, posterior cingulate cortex in MDD is also observed ( Chen et al, 2017 ; Wu et al, 2017 ). Using resting-state functional magnetic resonance imaging (rs-fMRI), abnormal local brain activities in precuneus, cerebellum, lingual gyrus and inter-regional functional connectivity between subgenal anterior cingulate cortex and temporal cortex, between insula and thalamus, inferior parietal cortex, and between intraparietal sulcus and superior temporal gyrus (STG) were also identified ( Wu et al, 2016a ; Wang et al, 2017a , c ; Sun et al, 2018 ; Wang J. et al, 2018 ).…”

Distributed Subnetworks of Depression Defined by Direct Intracranial Neurophysiology

“…Recent computational advancements have introduced artificial intelligence in medical diagnostics with accuracies that rival physicians 22,23 . In psychiatry, studies have leveraged such data-driven approaches as well, applied to imaging modalities [24][25][26][27][28][29][30][31][32] or electrocorticography (EEG) 33,34 .…”

“…In addition to alterations in the spectral content of network activity in depression, previous studies have observed distinct deficiencies in connectivity across depression networks 27,28,[31][32][33] . A fundamental interest in neuroscience is the relationship between the brain's neural activity and its underlying functional and structural connectivity, which remains unknown.…”