Age-related neural activation differences in bipolar patients
MedWire News: Patients with bipolar disorder show age-related differences in the activation of neural circuitry that mediates motor inhibition, US researchers report.
Writing in the American Journal of Psychiatry, Judah Weathers (National Institute of Mental Health, Bethesda, Maryland, USA) and colleagues explain that previous studies "clearly implicate deficient motor inhibition in the adult form of the disorder, whereas data for pediatric bipolar disorder are less definitive."
To investigate further, the team compared the neural circuitry mediating motor inhibition in 16 children and 23 adults with bipolar disorder, and 21 children and 29 adults who were mentally healthy.
All of the participants underwent functional magnetic resonance imaging of the brain while performing a stop-signal task in which they were asked to press or refrain from pressing a button in response to "go" or "stop" signals on a screen.
Region-of-interest analysis revealed that, during failed inhibition, pediatric bipolar disorder patients showed reduced activity in the left and right anterior cingulate cortex compared with healthy children of a similar age and adult bipolar disorder patients.
By contrast, adult bipolar disorder patients showed increased activation in the left anterior cingulate cortex relative to mentally healthy adults.
During successful inhibition, both children and adults with bipolar disorder showed reduced activation in the left ventral prefrontal cortex and the right nucleus compared with mentally healthy children and adults.
Further analyses indicated that differences between pediatric and adult patients with bipolar disorder regarding activity in the anterior cingulate cortex during failed inhibition were not due to differences in mood or medication status.
"Our study provides evidence of developmental differences in frontostriatal activation between bipolar patients and healthy subjects," conclude Weathers and team.
They add that further research addressing how brain activation and behavior progress in bipolar disorder "would help in the accurate diagnosis of pediatric bipolar disorder, in understanding age-specific deficits in bipolar disorder, and in applying intervention strategies appropriate for developmental stage in the illness."
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By Mark Cowen