Effects of genetic variants on neural circuits in major depression

2011 ◽  
Vol 26 (S2) ◽  
pp. 2085-2085
Author(s):  
T. Frodl
Keyword(s):  
Major Depressive Disorder ◽  
High Resolution ◽  
Cognitive Control ◽  
Depressive Disorder ◽  
Early Life ◽  
Brain Regions ◽  
High Angular Resolution ◽  
Major Depressive ◽  
Early Life Adversity ◽  
Brain Changes

IntroductionThe underlying neurobiology of major depressive disorder (MDD) is likely to represent an interaction between genetic susceptibility and environmental factors like stress. There is growing evidence that epigenetic processes might mediate the effects of the social environment during childhood on gene expression.ObjectivesWe investigated in multimodal high-resolution MRI-genetic studies whether microstructural and functional brain changes are the result of gene-environment interactions.MethodsPatients with major depressive disorder (MDD), high-risk subjects for developing MDD and healthy participants were investigated using high-resolution magnetic resonance imaging (MRI), high angular resolution diffusion imaging (HARDI) and functional MRI. Furthermore, we assessed early life adversity and measured the serotonin transporter polymorphisms (5-HTTLPR).ResultsWe demonstrated that patients with MDD have smaller hippocampal and frontal cortex volumes associated with gen-environment interactions. Healthy Subjects at risk for developing depression, who manage to stay healthy, show better activation of the frontal cognitive control system. Those who had stronger fibre connections between frontal and temporal brain regions also better managed incidences of adversity in early life.ConclusionsStress x gene interactions seem to account for at least some of the structural brain changes. Resilience against environmental stressors might be associated with stronger neural fibre connections and more effective cognitive control networks.

SU56EPIGENETIC REGULATION OF THE NOVEL EARLY LIFE ADVERSITY RESPONSIVE GENE MORC1 IN MAJOR DEPRESSIVE DISORDER

2019 ◽  
Vol 29 ◽  
pp. S1297
Author(s):  
Mara Thomas ◽  
Vanessa Nieratschker ◽  
Nadine Provençal ◽  
Andressa Coope dos Santos Botezelli
Keyword(s):  
Major Depressive Disorder ◽  
Depressive Disorder ◽  
Early Life ◽  
The Novel ◽  
Major Depressive ◽  
Early Life Adversity ◽  
Responsive Gene

Axonal myelin increase in the callosal genu in depression but not schizophrenia

2015 ◽  
Vol 45 (10) ◽  
pp. 2145-2155 ◽  
Author(s):  
M. R. Williams ◽  
P. Sharma ◽  
K. L. Fung ◽  
R. K. B. Pearce ◽  
S. R. Hirsch ◽  
...  
Keyword(s):  
Major Depressive Disorder ◽  
High Resolution ◽  
Depressive Disorder ◽  
Sagittal Plane ◽  
Brain Regions ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Myelinated Axons ◽  
Major Depressive ◽  
Cross Sectional

BackgroundAbnormalities in the anterior inter-hemispheric connectivity have previously been implicated in major depressive disorder. Disruptions in fractional anisotropy in the callosum and fornix have been reported in schizophrenia and major depressive disorder. Oligodendrocyte density and overall size of the callosum and fornix show no alteration in either illness, suggesting that gross morphology is unchanged but more subtle organizational disruption may exist within these brain regions in mood and affective disorders.MethodUsing high-resolution oil-immersion microscopy we examined the cross-sectional area of the nerve fibre and the axonal myelin sheath, and using standard high-resolution light microscopy we measured the density of myelinated axons. These measurements were made in the genu of the corpus callosum and the medial body of the fornix at its most dorsal point. Measures were taken in the sagittal plane in the callosal genu and in the coronal plane at the most dorsal part of the fornix body.ResultsCases of major depressive disorder had significantly greater mean myelin cross-sectional area (p = 0.017) and myelin thickness (p = 0.004) per axon in the genu than in control or schizophrenia groups. There was no significant change in the density of myelinated axons, and no changes observed in the fornix.ConclusionThe results suggest a clear increase of myelin in the axons of the callosal genu in MDD, although this type of neuropathological study is unable to clarify whether this is caused by changes during life or has a developmental origin.

scholarly journals Cortical structural differences in major depressive disorder correlate with cell type-specific transcriptional signatures

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiao Li ◽  
Jakob Seidlitz ◽  
John Suckling ◽  
Feiyang Fan ◽  
Gong-Jun Ji ◽  
...  
Keyword(s):  
Gene Expression ◽  
Major Depressive Disorder ◽  
Depressive Disorder ◽  
Structural Changes ◽  
Brain Regions ◽  
Cell Type ◽  
Major Depressive ◽  
Structural Differences ◽  
Neuroimaging Data ◽  
Cell Type Specific

AbstractMajor depressive disorder (MDD) has been shown to be associated with structural abnormalities in a variety of spatially diverse brain regions. However, the correlation between brain structural changes in MDD and gene expression is unclear. Here, we examine the link between brain-wide gene expression and morphometric changes in individuals with MDD, using neuroimaging data from two independent cohorts and a publicly available transcriptomic dataset. Morphometric similarity network (MSN) analysis shows replicable cortical structural differences in individuals with MDD compared to control subjects. Using human brain gene expression data, we observe that the expression of MDD-associated genes spatially correlates with MSN differences. Analysis of cell type-specific signature genes suggests that microglia and neuronal specific transcriptional changes account for most of the observed correlation with MDD-specific MSN differences. Collectively, our findings link molecular and structural changes relevant for MDD.

Altered Brain Network Degree Centrality in Major Depressive Disorder via Electro-Acupuncture Stimulation at Baihui(gv20)

2021 ◽  
Author(s):  
Shasha Li ◽  
Ya Chen ◽  
Gaoxiong Duan ◽  
Yong Pang ◽  
Huimei Liu ◽  
...  
Keyword(s):  
Major Depressive Disorder ◽  
Depressive Disorder ◽  
Brain Function ◽  
Brain Regions ◽  
Brain Network ◽  
Degree Centrality ◽  
Major Depressive ◽  
Acupuncture Stimulation ◽  
Therapeutic Mechanisms ◽  
Abnormal Brain

Abstract Background: Although the acupuncture treatment of major depressive disorder(MDD) has been recognized by the latest clinical practice guidelines of the American Academy of Internal Medicine, complex therapeutic mechanisms need further to clarify. The aim of the study is investigate whether the aberrant resting state brain network in MDD patients could be regulated by acupuncture at GV20 using functional magnetic resonance imaging(fMRI) combined with degree centrality(DC) method. Results: Compared to healthy subjects, MDD patients exhibited significantly aberrant DC in widely brain regions, including cortical(PFC, precuneus, temporal, insula) and sub-cortical (thalamus, putamen and caudate) structures. Furthermore, results showed that acupuncture at GV20 induced down-regulation the DC of abnormal brain regions in MDD patients. Conclusions: Our findings provide imaging evidence to support that GV20-related acupuncture stimulation may modulate the abnormal brain function state in MDD patients by using fMRI technique combined with DC analysis. This study may partly interpret the neural mechanisms of acupuncture at GV20 which is used to treat patients with MDD in clinical. Trial registration: ChiCTR, ChiCTR-IOR-15006357. Registered 05 May 2015, http://www.chictr.org.cn/showproj.aspx?proj=10922.

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