title: Insula and amygdala resting-state functional connectivity differentiate bipolar from unipolar depression.
abstract: Distinguishing depressive episodes due to bipolar disorder (BD) or major depressive disorder (MDD) solely on clinical grounds is challenging. We aimed at comparing resting-state functional connectivity (rsFC) of regions subserving emotional regulation in similarly depressed BD and MDD.
  
  
  
  We enrolled 76 in-patients (BD, n = 36; MDD, n = 40) and 40 healthy controls (HC). A seed-based approach was used to identify regions showing different rsFC with the insula and the amygdala. Insular and amygdalar parcellations were then performed along with diagnostic accuracy of the main findings.
  
  
  
  Lower rsFC between the left insula and the left mid-dorsolateral prefrontal cortex and between bilateral insula and right frontopolar prefrontal cortex (FPPFC) was observed in BD compared to MDD and HC. These results were driven by the dorsal anterior and posterior insula (PI). Lower rsFC between the right amygdala and the left anterior hippocampus was observed in MDD compared to BD and HC. These results were driven by the centromedial and laterobasal amygdala. Left PI/right FPPC rsFC showed 78% accuracy differentiating BD and MDD.
  
  
  
  rsFC of amygdala and insula distinguished between depressed BD and MDD. The observed differences suggest the possibility of differential pathophysiological mechanisms of emotional dysfunction in bipolar and unipolar depression.
authors.affiliation: Beth K. and Stuart C. Yudofsky Division of Neuropsychiatry, Baylor College of Medicine, Houston, TX, USA.|Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA.|The Menninger Clinic, Houston, TX, USA.|Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Ambrosi
authors.affiliation: Beth K. and Stuart C. Yudofsky Division of Neuropsychiatry, Baylor College of Medicine, Houston, TX, USA.|Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA.
authors.forename: D B
authors.initials: DB
authors.lastname: Arciniegas
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA.|The Menninger Clinic, Houston, TX, USA.
authors.forename: A
authors.initials: A
authors.lastname: Madan
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA.|Michael E DeBakey VA Medical Center, Houston, TX, USA.
authors.forename: K N
authors.initials: KN
authors.lastname: Curtis
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA.|The Menninger Clinic, Houston, TX, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Patriquin
authors.affiliation: Beth K. and Stuart C. Yudofsky Division of Neuropsychiatry, Baylor College of Medicine, Houston, TX, USA.|Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA.|Michael E DeBakey VA Medical Center, Houston, TX, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Jorge
authors.affiliation: Beth K. and Stuart C. Yudofsky Division of Neuropsychiatry, Baylor College of Medicine, Houston, TX, USA.|Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA.|Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Spalletta
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA.|The Menninger Clinic, Houston, TX, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Fowler
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA.|Department of Psychology, University of Hawaii, Hilo, HI, USA.
authors.forename: B C
authors.initials: BC
authors.lastname: Frueh
authors.affiliation: Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA.|Michael E DeBakey VA Medical Center, Houston, TX, USA.
authors.forename: R
authors.identifier: 0000-0002-1105-566X
authors.initials: R
authors.lastname: Salas
mesh_terms: D000328:Adult; D000679:Amygdala / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001714:Bipolar Disorder / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000503:physiopathology*; D063132:Connectome / Q000379:methods*; D003865:Major Depressive Disorder / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D055815:Young Adult
keywords: bipolar disorder; depression; functional magnetic resonance imaging; major depression