Neuroimaging of the information processing flow in schizophrenia during the Stroop task using a spatially filtered MEG analysis

Abstract

We examined transient neural activations from the input of a stimulus to the output of a response during the Stroop task for schizophrenic subjects with/without auditory hallucinations using a spatial filtered technique, synthetic aperture magnetometry (SAM), which provides high temporal and spatial resolution. MEG signals from the presentation of incongruent stimuli to responses were analyzed with a time window of 200 ms in steps of 50 ms. According to our previous studies with healthy subjects, regions showing significant decrease of current source density (CSD) in the 25–60-Hz band, corresponding to event-related desynchronization, were regarded to be activated. The non-hallucinators showed neural activations in the inferior parietal or temporal regions in the early stage of information processing, and successive and temporally overlapping neural activations in the left dorsolateral prefrontal cortex (DLPFC) and primary motor area (M1). The hallucinators showed neural activations in the right DLPFC and M1. Our preliminary results suggest that the schizophrenic subjects showed transient neural activations along the fundamental information flow (sensory input system–executive control system–motor output system), and that lateralization of DLPFC might be related with auditory hallucinations in schizophrenia.