Right frontal event related EEG coherence (ERCoh) differentiates good from bad performers of the Wisconsin Card Sorting Test (WCST).

AIM: To investigate changes in Event-Related Coherence (ERCoh) associated to good and bad resolution of the Wisconsin Card Sorting Test (WCST). METHODS: Event-Related Potentials (ERPs) were recorded from a sample of 30 university students while they performed a computerized version of the WCST. ERCoh was calculated for frontal and parietal electrodes for two specific moments: immediately before the response and after the feedback cues. RESULTS: Bad performers presented significantly reduced ERCoh at the right frontal region (in alpha, beta-1 and beta-2 bands), while no consistent group differences emerged for parietal ERCoh. Furthermore, the strength of functional coupling (ERCoh) between midfrontal and right-frontal electrodes was a good predictor of WCST behavioural parameters, such as the percentage of perseverative errors or the number of categories achieved. CONCLUSIONS: The results suggest that the right prefrontal cortex is specifically involved in executive functions, such as planning and foresight, tapped by the WCST. Although the specificity of the WCST to explore frontal lesions has been recently questioned, the present findings support that prefrontal areas are specifically involved in the successful resolution of the test by healthy subjects.