title: Abnormal functional connectivity in posttraumatic stress disorder.
abstract: This study investigated the efficacy of a combined multivariate/resampling procedure for the analysis of PET activation studies. The covariance-based multivariate analysis was used to investigate distributed brain systems in posttraumatic stress disorder (PTSD) patients and matched controls during performance of a working memory task. The results were compared to univariate results obtained in an earlier study. We also examined whether the PTSD patients demonstrated a breakdown in functional connectivity that may be associated with working memory difficulties often experienced by these patients. A resampling procedure was used specifically to test the reliability of measured between-group effects, to avoid mistaken inference on the basis of random intersubject differences. Significant and reproducible differences in network connectivity were obtained for the two groups. The functional connectivity pattern of the patient group was characterized by relatively more activation in the bilateral inferior parietal lobes and the left precentral gyrus than the control group, and less activation in the inferior medial frontal lobe, bilateral middle frontal gyri and right inferior temporal gyrus. The resampling procedure provided direct evidence that working memory updating was abnormal in PTSD patients relative to matched controls. This work focuses on the need to identify extended brain networks (in addition to regionally specific changes) for the full characterization of brain responses in neuroimaging experiments. Our multivariate analysis explicitly measures the reliability of the patterns of functional connectivity we obtain and demonstrates the potential of such analyses for the study of brain network dysfunction in psychopathology.
authors.affiliation: School of Physics, University of Melbourne, Victoria 3010, Australia.
authors.forename: Marnie E
authors.initials: ME
authors.lastname: Shaw
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Strother
authors.forename: Alexander C
authors.initials: AC
authors.lastname: McFarlane
authors.forename: Philip
authors.initials: P
authors.lastname: Morris
authors.forename: Jon
authors.initials: J
authors.lastname: Anderson
authors.forename: C Richard
authors.initials: CR
authors.lastname: Clark
authors.forename: Gary F
authors.initials: GF
authors.lastname: Egan
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003118:Color Perception / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D009415:Nerve Net / Q000000981:diagnostic imaging* / Q000503:physiopathology; D009473:Neuronal Plasticity / Q000502:physiology*; D012153:Retention, Psychology / Q000502:physiology; D013313:Stress Disorders, Post-Traumatic / Q000000981:diagnostic imaging* / Q000503:physiopathology; D014055:Tomography, Emission-Computed; D014706:Verbal Learning / Q000502:physiology