called parallel independent component analysis, or pICA, reported Wenhau Jiang and his associates.
pICA is a technique that enables researchers to analyze several modalities and the interconnections between them. The approach, which is considered fairly new, has been applied most often to neuropsychiatric disorders (Front Genet. 2015;6:276). The pICA involves using structural MRI and the Positive and Negative Syndrome Scale (PANSS) scores to assess the relationship between gray matter concentration in different areas of the brain and bipolar mood characteristics.
In the current study, published in NeuroImage: Clinical, Mr. Jiang and his associates used data from 110 patients with bipolar I and bipolar II from a large study conducted at the Norwegian Center for Mental Disorders Research in Oslo.
All patients were aged 18-65 years and had an IQ of over 70, and none had a history of severe head trauma. Most of the patients were women, about half had at least one psychotic episode, and all provided PANSS scores, reported Mr. Jiang of the department of psychology at Georgia State University in Atlanta and his associates.
After the patients were scanned, pICA was used to examine the preprocessed structural images and the PANSS item scores. The pICA showed two distinct profiles. One group showed preserved gray matter concentration in the right middle/superior temporal gyrus on the rMRI. These participants had more anxiety, and guilty feelings on the PANSS. Overall, participants with higher preserved gray matter concentration in bilateral, frontal, and parietal and left temporal regions show milder severity of these characteristics.
In the second pICA profile, participants with higher preserved gray matter concentration in bilateral front, parietal, and left temporal regions showed milder severity of several characteristics including blunted affect, emotional withdrawal, and passive/apathetic social withdrawal.
The investigators noted: “The mood profile was correlated with reductions in the right temporal gyrus, while the apathy/asocial profile correlated with a more widespread network including frontal, temporal, and parietal regions. It implicated the GM [gray matter] deficits in regional temporal lobe and frontal-temporal-parietal circuits that were separately related to clinical profiles as mood and apathy.”
The study was supported by the National Institutes of Health, the Research Council of Norway, the South-East Norway Health Authority, and the European Community’s Seventh Framework Programme. No author disclosures were stated.
SOURCE: Jiang W et al. Neuroimage Clin. 2019 Aug 19. doi: 10.1016/j.nicl.2019.101989.