|Beitragstitel||Relating reduced white matter microstructure in patients at clinical risk for psychosis to cognitive performance on a probabilistic reward task|
Schizophrenia is assumed as a neurodevelopmental disorder indicated by structural brain abnormalities. Previous research reported reduced integrity of white matter in schizophrenia linked to cognitive deficits. Here, we aim to shed new light on early detection of psychotic disorders by investigating the association of reduced white matter microstructure and cognitive impairments in a clinical risk population.
We investigated white matter integrity by using 3.0 Tesla diffusion tensor imaging MRI measuring fractional anisotropy (FA) and cognitive performance by conducting a probabilistic reward task (PRT) in 91 patients from the Bern early detection service and 46 healthy controls.
At first, we compared measurements of PRT performance between groups. As expected, two-way ANOVAs revealed significant main effects (p < 0.005) with greater accuracy and shorter response time for the stimulus condition of high in comparison to low reward. In addition, there was a significant main effect of group (p < 0.001) with longer response time of patients in contrast to healthy controls, whereas no group difference was observable in accuracy. Subsequently contrasting FA measurements between groups, our analyses revealed a cluster with significant reduction in white matter integrity centered in the corpus callosum (p < 0.05, corrected for multiple comparisons) of the patients in comparison to healthy subjects. Finally, we conducted correlational analyses between PRT behavior measurements and FA values extracted from the previously identified cluster of interest in the corpus callosum over the whole sample. Based on previous research, we expected negative correlations between the response time and white matter integrity. Here, we observed only marginally significant negative correlations (p < 0.1) between the response time averaged over the first 100 trials (1. Block) and FA values, indicating a weak association during the early habituation phase of the task. Interestingly, an additional correlational analysis between FA values and the overall task accuracy revealed a positive correlation (p < 0.05), over the whole sample.
Taken together, our findings highlight associations of white matter integrity in the corpus callosum and cognitive deficits in patients at clinical risk for psychosis.