Deficits in fronto-posterior interactions point to inefficient resource allocation in schizophrenia.
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.
Sharma
A
A
Department of General Psychiatry, Centre for Psychosocial Medicine, University of Heidelberg, Germany. Anuradha.Sharma@med.uni-heidelberg.de
Weisbrod
M
M
Kaiser
S
S
Markela-Lerenc
J
J
Bender
S
S
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