Summary: A large meta-analysis identifies shared dysfunction in neurocognitive networks across multiple psychiatric disorders.
Source: Elsevier.
Researchers report consistent alterations in functional connectivity among three core brain networks involved in higher cognition—changes that appear across a range of psychiatric diagnoses and that map to regions linked with general cognitive performance. The findings, published in Biological Psychiatry, suggest these network disruptions help explain the overlapping cognitive deficits seen in many psychiatric conditions.
A comprehensive meta-analysis that combined data from hundreds of brain imaging studies found reproducible changes in connectivity in three large-scale networks critical for complex thought: the default mode network (DMN), the frontoparietal network (FPN), and the salience network (SN). The review integrated results from 242 resting-state functional magnetic resonance imaging (fMRI) studies covering several psychiatric disorders. Complementary analysis of 363 structural imaging studies revealed gray matter reductions localized within those same networks, strengthening the link between structural and functional brain changes.
Yong He, PhD (Beijing Normal University), the study’s senior author, emphasizes that these results provide the first meta-analytic evidence of shared functional connectivity disruptions across diagnoses. According to the authors, this convergence supports the idea that cognitive dysfunction in psychiatry may stem from overlapping network-level pathology rather than strictly disorder-specific brain changes.
John Krystal, MD, Editor of Biological Psychiatry, commented that the findings challenge the current role of neuroimaging in psychiatric diagnosis. The study suggests that many neuroimaging measures may reflect common symptom-related pathology that cuts across traditional diagnostic categories, which could explain why neuroimaging biomarkers have not yet translated into routine diagnostic tools.
The overlap in cognitive impairment across psychiatric disorders is a long-standing clinical challenge. Most psychiatric illnesses feature deficits in attention, memory, executive function, or processing speed, making it difficult to neatly categorize patients based on symptoms alone. Over the past decades, neuroimaging has clarified many neural correlates of mental health conditions, but robust brain-based diagnostic markers remain elusive. This meta-analysis indicates that one reason may be the prominence of shared network dysfunctions that are not unique to any single diagnosis.
Specifically, the meta-analysis found a patterned change in connectivity among the DMN, FPN, and SN: reduced connectivity (hypoconnectivity) was observed between the DMN and the ventral portion of the SN and between the SN and the FPN, while increased connectivity (hyperconnectivity) appeared between the DMN and the FPN and between the DMN and the dorsal SN. These altered interactions corresponded with regional gray matter reductions and were localized to brain regions that support general cognitive abilities. In other words, structural brain changes appear tightly linked to functional network disturbances in areas crucial for cognition.
The authors argue that these shared network disturbances could represent a common mechanism underlying generalized cognitive deficits across psychiatric disorders. If so, future biomarker research should account for these common elements when searching for disease-specific signals. Adjusting for overlapping network pathology may be necessary to reveal subtle, disorder-specific biology that current studies have missed.
Source: Rhiannon Bugno – Elsevier
Publisher: Organized by NeuroscienceNews.com
Image source: Public domain image used by NeuroscienceNews.com
Original research: Abstract for “Common Dysfunction of Large-Scale Neurocognitive Networks Across Psychiatric Disorders” by Zhiqiang Sha, Tor D. Wager, Andrea Mechelli, Yong He, published in Biological Psychiatry, January 3, 2019.
doi: 10.1016/j.biopsych.2018.11.011
Elsevier. Disrupted Networks Link Overlapping Cognitive Deficits in Psychiatric Disorder. NeuroscienceNews. January 3, 2019.
Abstract
Common Dysfunction of Large-Scale Neurocognitive Networks Across Psychiatric Disorders
Background
Cognitive impairment is a core feature across many psychiatric conditions, yet the neural basis of these shared deficits is not well understood. This study aimed to identify functional connectivity and structural brain changes that are common across psychiatric diagnoses, focusing on three neurocognitive networks: the default mode network (DMN), the frontoparietal network (FPN), and the salience network (SN).
Methods
Meta-analyses were performed on resting-state whole-brain seed-based functional connectivity data from 8,298 patients and 8,165 healthy controls spanning eight psychiatric disorders. A voxel-based morphometry meta-analysis of structural MRI data included 14,027 patients and 14,504 healthy controls. To contextualize the findings, cognitive performance and network associations were also examined in a separate sample of 776 healthy participants from the Human Connectome Project.
Results
Across psychiatric disorders, the DMN, FPN, and SN showed a consistent pattern of altered connectivity. Hypoconnectivity emerged between the DMN and ventral SN and between the SN and FPN. In contrast, hyperconnectivity was found between the DMN and FPN and between the DMN and dorsal SN. These functional connectivity patterns co-occurred with localized gray matter reductions and were concentrated in regions that contribute to general cognitive performance.
Conclusions
This meta-analysis provides the first large-scale evidence of shared alterations in functional connectivity within and between major neurocognitive networks across psychiatric disorders. The pattern of network interactions reported here may underlie the widespread cognitive deficits observed in psychiatric populations and highlights the need to consider cross-diagnostic network dysfunction when developing neuroimaging biomarkers.