Discovery of a common brain network for psychiatric illnesses

Summary: By studying four sets of pre-existing, publicly available psychological and neurological data, researchers have identified a network of brain areas that underlie psychiatric disorders, including depression, anxiety, bipolar disorder and schizophrenia.

Source: Brigham and Women’s Hospital

Psychiatric illnesses, such as schizophrenia and depression, affect nearly one in five adults in the United States, and nearly half of patients diagnosed with a psychiatric illness also meet the criteria for one second.

With so much overlap, researchers began to suspect that there might be a neurobiological explanation for a variety of psychiatric illnesses.

A new study by researchers at Brigham and Women’s Hospital, a founding member of the Mass General Brigham Health System, investigated four pre-existing, publicly available neurological and psychiatric datasets and identified a network of underlying brain areas. to psychiatric illnesses.

Their results are published in Nature Human behavior.

“Traditionally, neurology and psychiatry have different diagnostic strategies,” said corresponding author Joseph J. Taylor, MD, Ph.D., medical director of transcranial magnetic stimulation at Brigham’s Center for Brain Circuit Therapeutics and psychiatrist associated with Brigham’s Department of Psychiatry.

“Neurology asks, ‘Where is the lesion?’ and psychiatry asks, “What are the symptoms?” We now have tools to explore the “where” question for psychiatric disorders. In this study, we investigated whether psychiatric disorders share a common brain network.

The researchers began by analyzing a structural brain dataset from more than 15,000 healthy controls as well as patients diagnosed with schizophrenia, bipolar disorder, depression, addiction, obsessive-compulsive disorder or anxiety. They found decreased gray matter in the anterior cingulate and insula, two brain regions commonly associated with psychiatric illnesses.

However, only a third of the studies showed a decrease in gray matter in these brain regions. Additionally, neurodegenerative diseases have also shown decreases in gray matter in these same regions.

To address these shortcomings, the team used the human connectome (a wiring diagram of the human brain) to test whether gray matter changes in psychiatric illnesses were more effectively mapped to a common brain network than to common brain regions. .

The researchers discovered a transdiagnostic network in which up to 85% of studies showed a decrease in gray matter. This network was specific to gray matter decreases in psychiatric versus neurodegenerative disorders.

They then performed the same analyzes omitting data for one psychiatric diagnosis at a time. The transdiagnostic network remained robust, suggesting that no psychiatric illness was disproportionately responsible for the identified network.

In subsequent analyzes of a dataset including brain imaging of 194 veterans with and without penetrating head trauma along with their psychiatric diagnoses, the researchers overlaid the lesions on the transdiagnostic network and found that the damage induced by the lesions in the network were correlated with a higher likelihood of multiple psychiatric disorders. diseases.

They also used veterans’ data to independently derive a transdiagnostic network based on brain damage associated with psychiatric illness. They found that this injury-based psychiatric network was very similar to their atrophy-based psychiatric network, although it was derived from a completely different dataset.

Finally, the team used data from neurosurgical ablations for patients with extreme and otherwise incurable psychiatric illnesses. These ablation targets aligned with the transdiagnostic network.

This shows the outline of a woman
They found decreased gray matter in the anterior cingulate and insula, two brain regions commonly associated with psychiatric illnesses. Image is in public domain

Most surprisingly, Taylor said, their findings appear to challenge the idea that decreased gray matter in the anterior cingulate and insula is causally linked to psychiatric illness.

“We found that damage to these regions was correlated with less psychiatric illness, no more, so the atrophy of that cingulate and insula may be a consequence or compensation for the psychiatric illness rather than a cause of it,” Taylor said.

Instead, their analyzes indicate that the posterior parietal cortex is the brain network node most likely to be causally associated with psychiatric illness.

By identifying an important, sensitive, and specific transdiagnostic network for psychiatric illnesses, the team has opened up a number of possible new directions for follow-up studies, including analyzing existing fMRI datasets to see if patterns of neuronal activation follow the same circuit and the same circuit of investigation. -differences based on psychiatric disorders. Taylor also plans to use transcranial magnetic stimulation (TMS) to modulate the network, specifically using the posterior parietal region as a target.

See also

This shows brain scans from the study

“Psychiatric disorders are brain disorders, and now we’re just beginning to have the tools to study and modulate their underlying circuitry,” Taylor said. “There may be more commonalities between these disorders than we initially thought.”

About this psychiatry and mental health research news

Author: Press office
Source: Brigham and Women’s Hospital
Contact: Press Office – Brigham and Women’s Hospital
Picture: Image is in public domain

Original research: Access closed.
“A transdiagnostic network for psychiatric illnesses derived from atrophy and injury” by Joseph Taylor, et al. Nature Human behavior


Summary

A transdiagnostic network of psychiatric illnesses derived from atrophy and injury

Psychiatric disorders share neurobiology and are frequently co-occurring. This neurobiological and clinical overlap highlights the opportunities for transdiagnostic treatments.

In this study, we used coordinate and lesion network mapping to test a shared brain network across psychiatric disorders. In our meta-analysis of 193 studies, atrophy coordinates across six psychiatric disorders mapped onto a common brain network defined by positive connectivity to the anterior cingulate and insula, and negative connectivity to the posterior parietal and occipital cortex lateral.

This network was robust to cross-validation without diagnosis and specific to atrophy coordinates of psychiatric versus neurodegenerative disorders (72 studies). In 194 patients who had suffered a penetrating head trauma, the damage to this network was correlated with the number of post-injury psychiatric diagnoses. Neurosurgical ablation targets for psychiatric diseases (four targets) also aligned to the array.

This convergent brain network for psychiatric illnesses may partly explain the high rates of psychiatric comorbidity and could highlight neuromodulation targets for patients with more than one psychiatric disorder.

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