title: Functional connectivity of dissociation in patients with psychogenic non-epileptic seizures.
abstract: BACKGROUND
  Psychogenic non-epileptic seizures (PNES) resemble epileptic seizures, but lack epileptiform brain activity. Instead, the cause is assumed to be psychogenic. An abnormal coping strategy may be exhibited by PNES patients, as indicated by their increased tendency to dissociate. Investigation of resting-state networks may reveal altered routes of information and emotion processing in PNES patients. The authors therefore investigated whether PNES patients differ from healthy controls in their resting-state functional connectivity characteristics and whether these connections are associated with the tendency to dissociate.
  
  
  METHODS
  11 PNES patients without psychiatric comorbidity and 12 healthy controls underwent task-related paradigms (picture-encoding and Stroop paradigms) and resting-state functional MRI (rsfMRI). Global cognitive performance was tested using the Raven's Matrices test and participants completed questionnaires for evaluating dissociation. Functional connectivity analysis on rsfMRI was based on seed regions extracted from task-related fMRI activation maps.
  
  
  RESULTS
  The patients displayed a significantly lower cognitive performance and significantly higher dissociation scores. No significant differences were found between the picture-encoding and Stroop colour-naming activation maps between controls and patients with PNES. However, functional connectivity maps from the rsfMRI were statistically different. For PNES patients, stronger connectivity values between areas involved in emotion (insula), executive control (inferior frontal gyrus and parietal cortex) and movement (precentral sulcus) were observed, which were significantly associated with dissociation scores.
  
  
  CONCLUSIONS
  The abnormal, strong functional connectivity in PNES patients provides a neurophysiological correlate for the underlying psychoform and somatoform dissociation mechanism where emotion can influence executive control, resulting in altered motor function (eg, seizure-like episodes).
authors: Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands.
authors: Sylvie J M
authors: SJ
authors: van der Kruijs
authors: Nynke M G
authors: NM
authors: Bodde
authors: Maarten J
authors: MJ
authors: Vaessen
authors: Richard H C
authors: RH
authors: Lazeron
authors: Kristl
authors: K
authors: Vonck
authors: Paul
authors: P
authors: Boon
authors: Paul A M
authors: PA
authors: Hofman
authors: Walter H
authors: WH
authors: Backes
authors: Albert P
authors: AP
authors: Aldenkamp
authors: Jacobus F A
authors: JF
authors: Jansen
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000503:physiopathology; D016022:Case-Control Studies; D004213:Dissociative Disorders / Q000503:physiopathology*; D004569:Electroencephalography; D004644:Emotions / Q000502:physiology; D056344:Executive Function / Q000502:physiology; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000503:physiopathology; D009483:Neuropsychological Tests; D011602:Psychophysiologic Disorders / Q000503:physiopathology*; D012640:Seizures / Q000209:etiology / Q000503:physiopathology*; D057190:Stroop Test; D055815:Young Adult