title: Disturbed cortico-amygdalar functional connectivity as pathophysiological correlate of working memory deficits in bipolar affective disorder.
abstract: Patients suffering from bipolar affective disorder show deficits in working memory functions. In a previous functional magnetic resonance imaging study, we observed an abnormal hyperactivity of the amygdala in bipolar patients during articulatory rehearsal in verbal working memory. In the present study, we investigated the dynamic neurofunctional interactions between the right amygdala and the brain systems that underlie verbal working memory in both bipolar patients and healthy controls. In total, 18 euthymic bipolar patients and 18 healthy controls performed a modified version of the Sternberg item-recognition (working memory) task. We used the psychophysiological interaction approach in order to assess functional connectivity between the right amygdala and the brain regions involved in verbal working memory. In healthy subjects, we found significant negative functional interactions between the right amygdala and multiple cortical brain areas involved in verbal working memory. In comparison with the healthy control subjects, bipolar patients exhibited significantly reduced functional interactions of the right amygdala particularly with the right-hemispheric, i.e., ipsilateral, cortical regions supporting verbal working memory. Together with our previous finding of amygdala hyperactivity in bipolar patients during verbal rehearsal, the present results suggest that a disturbed right-hemispheric "cognitive-emotional" interaction between the amygdala and cortical brain regions underlying working memory may be responsible for amygdala hyperactivation and affects verbal working memory (deficits) in bipolar patients.
authors.affiliation: University Hospital of Psychiatry, University of Bern, Bern, Switzerland, stegmayer@puk.unibe.ch.
authors.forename: Katharina
authors.initials: K
authors.lastname: Stegmayer
authors.forename: Juliana
authors.initials: J
authors.lastname: Usher
authors.forename: Sarah
authors.initials: S
authors.lastname: Trost
authors.forename: Ilona
authors.initials: I
authors.lastname: Henseler
authors.forename: Heike
authors.initials: H
authors.lastname: Tost
authors.forename: Marcella
authors.initials: M
authors.lastname: Rietschel
authors.forename: Peter
authors.initials: P
authors.lastname: Falkai
authors.forename: Oliver
authors.initials: O
authors.lastname: Gruber
mesh_terms: D000328:Adult; D000679:Amygdala / Q000098:blood supply / Q000473:pathology*; D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000150:complications* / Q000473:pathology*; D002540:Cerebral Cortex / Q000098:blood supply / Q000473:pathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000209:etiology*; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009434:Neural Pathways / Q000098:blood supply / Q000503:physiopathology*; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D011569:Psychiatric Status Rating Scales; D011601:Psychophysics; D014706:Verbal Learning; D055815:Young Adult
chemical_list: D010100:Oxygen