title: Increased cortical recruitment in Huntington's disease using a Simon task.
abstract: Cognitive deficits in Huntington's disease (HD) have been attributed to neuronal degeneration within the striatum; however, postmortem and structural imaging studies have revealed more widespread morphological changes. To examine the impact of HD-related changes in regions outside the striatum, we used functional magnetic resonance imaging (fMRI) in HD to examine brain activation patterns using a Simon task that required a button press response to either congruent or incongruent arrow stimuli. Twenty mild to moderate stage HD patients and 17 healthy controls were scanned using a 3T GE scanner. Data analysis involved the use of statistical parametric mapping software with a random effects analysis model to investigate group differences brain activation patterns compared to baseline. HD patients recruited frontal and parietal cortical regions to perform the task, and also showed significantly greater activation, compared to controls, in the caudal anterior cingulate, insula, inferior parietal lobules, superior temporal gyrus bilaterally, right inferior frontal gyrus, right precuneus/superior parietal lobule, left precentral gyrus, and left dorsal premotor cortex. The significantly increased activation in anterior cingulate-frontal-motor-parietal cortex in HD may represent a primary dysfunction due to direct cell loss or damage in cortical regions, and/or a secondary compensatory mechanism of increased cortical recruitment due to primary striatal deficits.
authors.affiliation: School of Psychology, Psychiatry and Psychological Medicine, Monash University, Clayton, Victoria 3800, Australia. nellie.georgiou-karistianis@med.monash.edu.au
authors.forename: Nellie
authors.initials: N
authors.lastname: Georgiou-Karistianis
authors.forename: Anusha
authors.initials: A
authors.lastname: Sritharan
authors.forename: Maree
authors.initials: M
authors.lastname: Farrow
authors.forename: Ross
authors.initials: R
authors.lastname: Cunnington
authors.forename: Julie
authors.initials: J
authors.lastname: Stout
authors.forename: John
authors.initials: J
authors.lastname: Bradshaw
authors.forename: Andrew
authors.initials: A
authors.lastname: Churchyard
authors.forename: Tamara-Leigh
authors.initials: TL
authors.lastname: Brawn
authors.forename: Phyllis
authors.initials: P
authors.lastname: Chua
authors.forename: Edmond
authors.initials: E
authors.lastname: Chiu
authors.forename: Dhananjay
authors.initials: D
authors.lastname: Thiruvady
authors.forename: Gary
authors.initials: G
authors.lastname: Egan
mesh_terms: D000328:Adult; D001931:Brain Mapping; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000098:blood supply / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006816:Huntington Disease / Q000473:pathology* / Q000503:physiopathology*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D013028:Space Perception / Q000502:physiology*