title: The polygenic risk for bipolar disorder influences brain regional function relating to visual and default state processing of emotional information.
abstract: Genome-wise association studies have identified a number of common single-nucleotide polymorphisms (SNPs), each of small effect, associated with risk to bipolar disorder (BD). Several risk-conferring SNPs have been individually shown to influence regional brain activation thus linking genetic risk for BD to altered brain function. The current study examined whether the polygenic risk score method, which models the cumulative load of all known risk-conferring SNPs, may be useful in the identification of brain regions whose function may be related to the polygenic architecture of BD. We calculated the individual polygenic risk score for BD (PGR-BD) in forty-one patients with the disorder, twenty-five unaffected first-degree relatives and forty-six unrelated healthy controls using the most recent Psychiatric Genomics Consortium data. Functional magnetic resonance imaging was used to define task-related brain activation patterns in response to facial affect and working memory processing. We found significant effects of the PGR-BD score on task-related activation irrespective of diagnostic group. There was a negative association between the PGR-BD score and activation in the visual association cortex during facial affect processing. In contrast, the PGR-BD score was associated with failure to deactivate the ventromedial prefrontal region of the default mode network during working memory processing. These results are consistent with the threshold-liability model of BD, and demonstrate the usefulness of the PGR-BD score in identifying brain functional alternations associated with vulnerability to BD. Additionally, our findings suggest that the polygenic architecture of BD is not regionally confined but impacts on the task-dependent recruitment of multiple brain regions.
authors.affiliation: Department of Psychology, School of Arts and Social Sciences, City, University of London, London, UK; Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK; NIHR BRC for Mental Health, Institute of Psychiatry, Psychology and Neuroscience, King's College London and SLaM NHS Trust, London, UK.
authors.forename: Danai
authors.initials: D
authors.lastname: Dima
authors.affiliation: NIHR BRC for Mental Health, Institute of Psychiatry, Psychology and Neuroscience, King's College London and SLaM NHS Trust, London, UK; MRC Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
authors.forename: Simone
authors.initials: S
authors.lastname: de Jong
authors.affiliation: NIHR BRC for Mental Health, Institute of Psychiatry, Psychology and Neuroscience, King's College London and SLaM NHS Trust, London, UK; MRC Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
authors.forename: Gerome
authors.initials: G
authors.lastname: Breen
authors.affiliation: Department of Psychiatry, Icahn School of Medicine at Mount Sinai, USA.
authors.forename: Sophia
authors.initials: S
authors.lastname: Frangou
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000000981:diagnostic imaging / Q000235:genetics / Q000503:physiopathology; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004644:Emotions / Q000502:physiology*; D005149:Facial Expression; D000066499:Facial Recognition / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D020412:Multifactorial Inheritance; D009679:Nuclear Family; D012306:Risk
keywords: Bipolar disorder; Facial affect; Polygenic risk score; Visual; Working memory; fMRI