title: Structural brain correlates of response inhibition in Bipolar Disorder I.
abstract: Deficits in response inhibition are a prominent feature of Bipolar Disorder, type I (BDI). The purpose of this study was to examine the relationship between inhibitory control and cerebral structure as it may inform our understanding of the pathophysiology of BDI. Inhibitory control was measured in remitted patients with BDI (n = 44) and healthy controls (n = 44), using the interference score from the Stroop Colour Word Task and the scaled total error score from the Hayling Sentence Completion Test. Structural magnetic resonance imaging brain scans were also obtained for all participants. For both measures, better performance in controls correlated positively with gray matter volume in the dorsal and ventral prefrontal cortical (PFC) regions with parietal involvement additionally seen for the interference score. In contrast, better inhibitory control in BDI patients correlated positively with gray matter volume in the right parietal cortical regions, namely the cuneus for the scaled total error score and the inferior parietal lobule for the interference score. The observed lack of correlation between PFC grey matter and measures of inhibitory control in BDI patients is suggestive of PFC dysfunction; the correlation between response inhibition and parietal grey matter volume may be indicative of a compensatory involvement of the parietal cortices in BDI.
authors.affiliation: Section of Neurobiology of Psychosis (Box P066), Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK.
authors.forename: Morgan
authors.initials: M
authors.lastname: Haldane
authors.forename: Giles
authors.initials: G
authors.lastname: Cunningham
authors.forename: Chris
authors.initials: C
authors.lastname: Androutsos
authors.forename: Sophia
authors.initials: S
authors.lastname: Frangou
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology; D001714:Bipolar Disorder / Q000503:physiopathology*; D001931:Brain Mapping; D003118:Color Perception / Q000502:physiology; D003220:Conflict, Psychological; D004193:Discrimination Learning / Q000502:physiology; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007266:Inhibition, Psychological; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000473:pathology / Q000503:physiopathology*; D017397:Prefrontal Cortex / Q000473:pathology / Q000503:physiopathology*; D012660:Semantics