Use of swLORETA to localize the cortical sources of target- and distracter-elicited P300 components.

OBJECTIVE

Cognitive event-related potentials (especially P300) have long been used to explore attentional processes. The aim of this study was to identify the cortical areas involved in P300 generation during a selective attention task.

METHODS

128 channel electroencephalograms were recorded in 15 healthy controls performing a three-stimulus visual oddball paradigm, in order to identify distracter- and target-elicited P300 components. For each subject, the P300 sources were localized using standardized weighted low-resolution electromagnetic tomography (swLORETA). One sample and paired T-tests were performed using SPM5®.

RESULTS

Common sources for both P300 components were observed within a large frontoparietal network, including the frontal eye field and dorsal parietal cortex (i.e. the attentional dorsal frontoparietal network). More inferior parietal areas, prefrontal and cingulate cortices (i.e. the attentional ventral frontoparietal network) were also involved in the generation of target-elicited P300.

CONCLUSIONS

These results suggest that distracter- and target-elicited P300 are both generated by the dorsal frontoparietal network. Moreover, target processing recruits a specific ventral network.

SIGNIFICANCE

Our data agree with the literature reports using other methods and should help to improve our knowledge of the cerebral networks underlying attentional processes.