title: Deficits in fronto-posterior interactions point to inefficient resource allocation in schizophrenia.
abstract: OBJECTIVE
  Fronto-posterior networks have been implicated in various cognitive processes that are impaired in schizophrenia. This is the first study on time and frequency resolved fronto-posterior coherence during cognitive control in schizophrenia.
  
  
  METHODS
  We examined 16 schizophrenic/schizoaffective patients and 20 age-matched controls performing a choice-reaction task. Fronto-posterior coherence was analyzed for event-related increases with respect to the inter-trial interval. Furthermore, we compared the two groups for event-related coherence during the task-related time intervals which showed a significant coherence increase with respect to the inter-trial interval, as well as for absolute coherence during the inter-trial interval.
  
  
  RESULTS
  Event-related coherence was significantly reduced in patients during time intervals (0-250 ms poststimulus) when controls showed significant event-related coherence increases. However, patients showed significantly higher absolute coherence during the inter-trial interval. These results pointed to differential deficits in fronto-posterior connectivity during the inter-trial interval and task-related conditions in schizophrenia.
  
  
  CONCLUSIONS
  Cognitive deficits in schizophrenia might be driven by abnormal fronto-posterior communication. Task-related hypo-connectivity and inter-trial interval hyper-connectivity point to resource allocation deficits. The timing of cortico-cortical interactions during crucial task-related intervals may be impaired, while frontal and posterior areas may exhibit increased interactions between the trials.
authors.affiliation: Department of General Psychiatry, Centre for Psychosocial Medicine, University of Heidelberg, Germany. Anuradha.Sharma@med.uni-heidelberg.de
authors.forename: A
authors.initials: A
authors.lastname: Sharma
authors.forename: M
authors.initials: M
authors.lastname: Weisbrod
authors.forename: S
authors.initials: S
authors.lastname: Kaiser
authors.forename: J
authors.initials: J
authors.lastname: Markela-Lerenc
authors.forename: S
authors.initials: S
authors.lastname: Bender
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000503:physiopathology*; D011618:Psychotic Disorders / Q000503:physiopathology; D011930:Reaction Time; D012559:Schizophrenia / Q000503:physiopathology*; D057190:Stroop Test; D013647:Task Performance and Analysis; D055815:Young Adult