In schizophrenia, brain connectivity is disrupted
Schizophrenia, a neurodevelopmental disorder in which psychosis is one of the symptoms, is thought to arise from disorganization in brain connectivity and functional integration. Now, a new study in Biological psychiatry: cognitive neuroscience and neuroimagingpublished by Elsevier, finds differences in functional brain connectivity in people with and without psychosis and schizophrenia that could help researchers understand the neural underpinnings of this disease.
The cerebral cortex is organized hierarchically, anchored by the sensorimotor cortex on the one hand and by multimodal association areas on the other, with the task of integrating incoming sensory information with internal and external sensory signals. The loss of executive control in schizophrenia may arise from disruption of this hierarchical signaling.
Alexander Holmes, a PhD candidate at Monash University who led the study, said: “We used brain scans and new mathematical techniques to investigate the hierarchical organization of the brains of individuals with early psychosis and established schizophrenia. This organization is important for health of the brain, because it regulates how we can effectively respond to and process stimuli from the outside world.”
The researchers used resting-state functional magnetic resonance imaging (fMRI) to measure gradients, an estimate of interregional functional coupling. Previous work had suggested that the primary sensory-visual gradient was disrupted in schizophrenia, but the current study instead showed that secondary processing of the sensorimotor-visual gradient was affected in people with the disease.
Holmes added: “We found that the organizational pattern distinguishing visual and sensorimotor pathways is significantly impaired in individuals with schizophrenia, but not in individuals with early psychosis. We subsequently found that this impairment explains the behavioral and clinical symptoms of schizophrenia. Our results highlight that changes in brain organization provide valuable insights into the mechanisms of schizophrenia, allowing us to better understand the disease and its progression.”
Cameron Carter, MD, editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, said of the work: “These new approaches to testing mathematical models of the organization of circuits in the human brain are beginning to reveal the nature of the disruption of neural integration which underlies psychotic symptoms in people with schizophrenia. Targeting these changes offers a new approach to how we think about developing treatments for this often difficult-to-treat disease. “
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