Neural correlates of response inhibition in pediatric bipolar disorder and attention deficit hyperactivity disorder
Alessandra M Passarotti1, John A Sweeney, Mani N Pavuluri
1Center for Cognitive Medicine, University of Illinois Medical Center at Chicago, Chicago, IL 60612, USA. apassarotti@psych.uic.edu
Insights
Pediatric bipolar disorder (PBD) and attention deficit hyperactivity disorder (ADHD) share response inhibition deficits. While both groups showed prefrontal dysfunction compared to healthy controls, ADHD additionally exhibited subcortical overactivity.
Area of Science:
- Neuroscience
- Child and Adolescent Psychiatry
- Cognitive Psychology
Background:
- Impulsivity, inattention, and poor behavioral inhibition are common in pediatric bipolar disorder (PBD) and attention deficit hyperactivity disorder (ADHD).
- Understanding the neural underpinnings of these shared deficits is crucial for accurate diagnosis and targeted treatment.
Purpose of the Study:
- To investigate the similarities and differences in the neural substrates of response inhibition deficits in pediatric bipolar disorder (PBD) and attention deficit hyperactivity disorder (ADHD).
Main Methods:
- A functional magnetic resonance imaging (fMRI) study was conducted on 15 unmedicated PBD patients, 11 unmedicated ADHD patients, and 15 healthy controls (HC).
- Participants completed a response inhibition task requiring motor response suppression upon presentation of a stop cue.
- Behavioral performance and brain activation patterns during response inhibition were analyzed.
Main Results:
- Both PBD and ADHD groups exhibited poorer behavioral performance on response inhibition compared to HC.
- The ADHD group showed reduced activation in ventrolateral (VLPFC) and dorsolateral (DLPFC) prefrontal cortex and increased bilateral caudate activation relative to HC.
- The PBD group displayed decreased activation in the left VLPFC and right anterior cingulate cortex (ACC) compared to HC.
- Prefrontal dysfunction was evident in both PBD and ADHD groups, but more pronounced in ADHD, which also involved subcortical overactivity.
Conclusions:
- Pediatric bipolar disorder and ADHD share deficits in behavioral inhibition, reflected in distinct patterns of neural activation.
- ADHD is characterized by more widespread prefrontal dysfunction and subcortical overactivity during response inhibition compared to PBD.
- These findings highlight differential neural mechanisms underlying shared behavioral deficits in these pediatric disorders.
Abstract:
Impulsivity, inattention and poor behavioral inhibition are common deficits in pediatric bipolar disorder (PBD) and attention deficit hyperactivity disorder (ADHD). This study aimed to identify similarities and differences in the neural substrate of response inhibition deficits that are associated with these disorders. A functional magnetic resonance imaging (fMRI) study was conducted on 15 unmedicated PBD patients (Type I, manic/mixed), 11 unmedicated ADHD patients, and 15 healthy controls (HC) (mean age = 13.5 years; S.D. = 3.5). A response inhibition task examined the ability to inhibit a motor response to a target when a stop cue appeared shortly after. The PBD and ADHD groups did not differ on behavioral performance, although both groups were less accurate than the HC group. fMRI findings showed that for trials requiring response inhibition, the ADHD group, relative to the PBD and HC groups, demonstrated reduced activation in both ventrolateral (VLPFC) and dorsolateral (DLPFC) prefrontal cortex, and increased bilateral caudate activation compared with HC. The PBD group, relative to HC, showed decreased activation in the left VLPFC, at the junction of the inferior and middle frontal gyri, and in the right anterior cingulate cortex (ACC). Prefrontal dysfunction was observed in both the ADHD and PBD groups relative to HC, although it was more extensive and accompanied by subcortical overactivity in ADHD.
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