The neural correlates of non-spatial working memory in velocardiofacial syndrome (22q11.2 deletion syndrome)

• Published in: Neuropsychologia Vol. 45; no. 12; pp. 2863 - 2873
• Main Authors: Kates, Wendy R., Krauss, Beth R., AbdulSabur, Nuria, Colgan, Deirdre, Antshel, Kevin M., Higgins, Anne Marie, Shprintzen, Robert J.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2007; Elsevier; Elsevier Science
• Subjects: 22q11.2 deletion syndrome; Adolescent; Adult and adolescent clinical studies; Biological and medical sciences; Brain; Brain Hemisphere Functions; Child; Children; Cognitive Processes; Control Groups; Correlation; Diagnostic Tests; DiGeorge Syndrome - psychology; Family; Female; Frontal lobe; Functional MRI; Genetics; Humans; Image Processing, Computer-Assisted; Learning Disabilities; Learning Disorders - etiology; Learning Disorders - psychology; Magnetic Resonance Imaging; Male; Medical sciences; Memory, Short-Term - physiology; Nerve Net - physiology; Neurological Impairments; Neuropsychological Tests; Organic mental disorders. Neuropsychology; Parietal lobe; Phonology; Program Effectiveness; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Short Term Memory; Siblings; Spatial Ability; VCFS; Velocardiofacial syndrome; Wechsler Scales; Working memory; 22q11.2 deletion syndrome; VCFS; Frontal lobe; Velocardiofacial syndrome; Functional MRI; Parietal lobe; Working memory; Human; 22ql 1.2 deletion syndrome; Immunopathology; DiGeorge syndrome; Central nervous system; Cognition; Nuclear magnetic resonance imaging; Encephalon; Deletion; Functional imaging
• ISSN: 0028-3932; 1873-3514
• DOI: 10.1016/j.neuropsychologia.2007.05.007

Velocardiofacial syndrome (VCFS), also known as 22q11.2 deletion syndrome, is a neurogenetic disorder that is associated with both learning disabilities and a consistent neuropsychological phenotype, including deficits in executive function, visuospatial perception, and working memory. Anatomic imaging studies have identified significant volumetric reductions in the parietal lobe of individuals with VCFS, but several studies have reported that the frontal lobe is relatively preserved. We used functional magnetic resonance imaging to investigate the neural correlates of non-spatial working memory in 17 youths with VCFS, 10 of their unaffected siblings, and 10 community controls (with the same proportion of learning disabilities as the VCFS youths). Task performance of siblings tended to be more accurate than children with VCFS, who did not differ from community controls. All three-study groups recruited parietal regions that were equivalent in location and magnitude. Whereas the sibling group also recruited the dorsolateral prefrontal cortex (DLPFC), Broca's area, and anterior cingulate, DLPFC activation was absent in the whole brain analyses of children with VCFS and controls. Moreover, the magnitude of frontal activation in VCFS participants was restricted relative to both siblings and controls. These findings suggest that VCFS participants exhibit frontal hypoactivation that is not attributable to performance. In addition, VCFS children and controls (many with idiopathic learning disabilities) appear to rely on phonological rehearsal to hold information on line instead of the DLPFC. Despite previous anatomic MRI reports of preserved frontal lobe volumes in VCFS therefore, these fMRI findings suggest that the frontal component of the distributed network subserving executive function and working memory may be disrupted in youth with this disorder.