title: Emotion regulation deficits in euthymic bipolar I versus bipolar II disorder: a functional and diffusion-tensor imaging study.
abstract: OBJECTIVE
  Emotion regulation deficits are a core feature of bipolar disorder. However, their potential neurobiological underpinnings and existence beyond bipolar I disorder remain unexplored. Our main goal was to investigate whether both individuals with bipolar I and bipolar II disorder show deficits in emotion regulation during an attention control task, and to explore the neurophysiological underpinnings of this potential deficit.
  
  
  METHODS
  Twenty healthy controls, 16 euthymic participants with bipolar I disorder, and 19 euthymic participants with bipolar II disorder completed psychometric and clinical assessments, a neuroimaging emotion regulation paradigm, and an anatomical diffusion-weighted scan. Groups were matched for age, gender, and verbal IQ.
  
  
  RESULTS
  During the presence of emotional distracters, subjects with bipolar I disorder showed slowed reaction times to targets, and increased blood oxygenation level-dependent (BOLD) responses in the amygdala, accumbens, and dorsolateral prefrontal cortex, but not increased inverse functional connectivity between these prefrontal and subcortical areas, and altered white matter microstructure organization in the right uncinate fasciculus. Subjects with bipolar II disorder showed no altered reaction times, increased BOLD responses in the same brain areas, increased inverse functional connectivity between the prefrontal cortex and amygdala, and no abnormalities in white matter organization.
  
  
  CONCLUSIONS
  Participants with bipolar I disorder showed abnormalities in functional and anatomical connectivity between prefrontal cortices and subcortical structures in emotion regulation circuitry. However, these deficits did not extend to subjects with bipolar II disorder, suggesting fundamental differences in the pathophysiology of bipolar disorder subtypes.
authors.affiliation: MRC Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UK.|Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK.
authors.forename: Xavier
authors.initials: X
authors.lastname: Caseras
authors.affiliation: Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK.|Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Cardiff, UK.
authors.forename: Kevin
authors.initials: K
authors.lastname: Murphy
authors.affiliation: Mood Disorders Centre, School of Psychology, University of Exeter, Exeter, UK.
authors.forename: Natalia S
authors.initials: NS
authors.lastname: Lawrence
authors.affiliation: Departament de Psicologia Bàsica, Clínica i Psicobiologia, School of Psychology, Universitat Jaume I de Castelló, Castello, Spain.
authors.forename: Paola
authors.initials: P
authors.lastname: Fuentes-Claramonte
authors.affiliation: MRC Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UK.|Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK.
authors.forename: Jessica
authors.initials: J
authors.lastname: Watts
authors.affiliation: Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK.|Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Cardiff, UK.
authors.forename: Derek K
authors.initials: DK
authors.lastname: Jones
authors.affiliation: MRC Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UK.|Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK.|Mood and Brain Laboratory, Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Mary L
authors.initials: ML
authors.lastname: Phillips
mesh_terms: D000328:Adult; D000679:Amygdala / Q000473:pathology / Q000503:physiopathology; D001288:Attention; D001714:Bipolar Disorder / Q000145:classification / Q000473:pathology / Q000503:physiopathology* / Q000523:psychology; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D016022:Case-Control Studies; D056324:Diffusion Tensor Imaging; D004644:Emotions; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009714:Nucleus Accumbens / Q000473:pathology / Q000503:physiopathology; D017397:Prefrontal Cortex / Q000473:pathology / Q000503:physiopathology; D011930:Reaction Time; D000068356:Self-Control / Q000523:psychology*; D011795:Surveys and Questionnaires; D066127:White Matter / Q000473:pathology / Q000503:physiopathology
keywords: BOLD; DTI; bipolar disorder; emotion regulation; fMRI