Regional brain activation changes and abnormal functional connectivity of the ventrolateral prefrontal cortex during working memory processing in adults with attention-deficit/hyperactivity disorder.
Previous studies on working memory (WM) function in adults with attention-deficit/hyperactivity disorder (ADHD) suggested aberrant activation of the prefrontal cortex and the cerebellum. Although it has been hypothesized that activation differences in these regions most likely reflect aberrant frontocerebellar circuits, the functional coupling of these brain networks during cognitive performance has not been investigated so far. In this study, functional magnetic resonance imaging (fMRI) and both univariate and multivariate analytic techniques were used to investigate regional activation changes and functional connectivity differences during cognitive processing in healthy controls (n = 12) and ADHD adults (n = 12). Behavioral performance during a parametric verbal WM paradigm did not significantly differ between adults with ADHD and healthy controls. During the delay period of the activation task, however, ADHD patients showed significantly less activation in the left ventrolateral prefrontal cortex (VLPFC), as well as in cerebellar and occipital regions compared with healthy control subjects. In both groups, independent component analyses revealed a functional network comprising bilateral lateral prefrontal, striatal, and cingulate regions. ADHD adults had significantly lower connectivity in the bilateral VLPFC, the anterior cingulate cortex, the superior parietal lobule, and the cerebellum compared with healthy controls. Increased connectivity in ADHD adults was found in right prefrontal regions, the left dorsal cingulate cortex and the left cuneus. These findings suggest both regional brain activation deficits and functional connectivity changes of the VLPFC and the cerebellum as well as functional connectivity abnormalities of the anterior cingulate and the parietal cortex in ADHD adults during WM processing.
Wolf
Robert C
RC
Department of Psychiatry and Psychotherapy III, University of Ulm, Leimgrubenweg 12-14, 89075 Ulm, Germany. christian.wolf@uni-ulm.de
Plichta
Michael M
MM
Sambataro
Fabio
F
Fallgatter
Andreas J
AJ
Jacob
Christian
C
Lesch
Klaus-Peter
KP
Herrmann
Martin J
MJ
Schönfeldt-Lecuona
Carlos
C
Connemann
Bernhard J
BJ
Grön
Georg
G
Vasic
Nenad
N
D000293:Adolescent; D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D015999:Multivariate Analysis; D009434:Neural Pathways / Q000503:physiopathology; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000503:physiopathology*; D055815:Young Adult