IFG-LINS resting-state functional connectivity a possible risk marker of bipolar disorder
Among offspring of parents with bipolar disorder (OBP), resting-state functional connectivity (rsFC) between left inferior frontal gyrus (IFG) and clusters in the left insula (LINS) may be a risk marker for the development of bipolar disorder, suggests a study.
The authors analysed a subset of the Pittsburgh Bipolar Offspring Study, a longitudinal study of OBP and community controls. Acceptable rsFC data were available in 24 OBP, 20 offspring of control parents with nonbipolar psychopathology (OCP) and 27 healthy controls.
Using multivariate regression, the authors evaluated group differences in seed-based rsFC between the IFG and target clusters (LINS, lentiform nucleus [LENT] and midcingulate cortex [MCING]) after preprocessing steps. They then tested whether rsFC was associated with person-level risk score and with other dimensional measures.
There were no group differences in rsFC between IFG and target regions. Within the OBP group, risk score was negatively associated with IFG-LINS rsFC (p=0.002). Across groups, mood lability (a predictor of bipolar disorder) had a negative association with rsFC and target regions (p=0.0002) due to negative correlation with IFG-LINS (p=0.0003) and IFG-MCING (p=0.001) rsFC.
Group-level differences were not replicated, but IFG-LINS rsFC negatively correlated with a person-level risk score in OBP and with mood lability across the sample.
“OBP are at increased risk to develop bipolar disorder. Alterations in rsFC have been identified in OBP; however, replication has been limited and correlation with person-level risk is unknown,” the authors said.
“A recent study found reduced rsFC between IFG and LINS, LENT and MCING in OBP,” they added. [Biol Psychiatry 2017;81:718-727]