Schizophrenia patients exhibited a psychological abnormal appearance when they recognized objects related to themselves. This cognitive process is associated with self-referential processing. In this study, the self-referential memory (SRM) task was performed by 18 schizophrenia patients and 18 healthy controls. In the encoding stage of the SRM task, the behavioral experiment data and electroencephalogram (EEG) data were recorded in three experimental conditions (self-referential condition, other-referential condition, and physical condition). For data analysis, the electrophysiological performance of the time-frequency distribution, phase lag index (PLI) strengths, phase synchronization connectivity, and brain-network properties were assessed in schizophrenia patients compared to healthy controls. We found that schizophrenia patients exhibited abnormal alpha oscillation characteristics at the time of 100–300 ms poststimulus during the self-referential condition, which consisted of diminished time-frequency distributions over the prefrontal, parietal, and occipital regions; lower functional connectivity strengths of the PLI in the parietal and occipital areas; higher global efficiency and the lower characteristic path length; and nodal efficiency of local areas (increased nodal efficiency in temporal regions and decreased nodal efficiency in occipital region) for dynamic network topology properties. Furthermore, the evoked power of the alpha band during the self-referential condition was significantly correlated with the SRM bias score in the patients (r = 0.595, p = 0.009). These results provided electrophysiological evidence and supported the hypothesis that an abnormal alpha rhythm might be the principal factor of dysfunctional self-referential processing in schizophrenia patients.

Background There is a need for devices that allow reproducible stimulation of skin areas of humans for investigating somatosensory mapping of the whole‐body surface. However, their design is not simple, due to the magnetic field of MRI scanners. Purpose To accurately characterize the mapping of somatosensory presentation of the whole‐body surface of subjects during functional (f)MRI scans. Study Type Prospective. Population A water phantom and six healthy participants (age 23–27 years; two males) were recruited for the fMRI experiment. Field Strength/Sequence T1‐weighted magnetization‐prepared rapid acquisition gradient‐echo, T2*‐weighted gradient echo sequence at 3T. Assessment The stimulation device for somatotopic mapping was composed of three units: an air‐generating unit, a control unit, and an execution unit. The fMRI in response to tactile stimulation was measured to characterize somatotopic mapping of the right‐side body consisting of hand, arm, and leg in six healthy subjects. Statistical Tests Pared‐samples t‐test for the conditions in SII. Results The pneumatical‐mechanical tactile stimulation offered a wide range of stimulation intensities (0–400 g) in each channel. The predetermined physical pressure was successfully reached within ~5 msec and returned to baseline within 5 msec after the end of stimulation. With this tactile device, the digressive rate of the signal‐to‐noise ratio (SNR) (271.44 without the device, 269.68 with the device) was 0.65% in the magnetic field environment. For the fMRI experiment, the primary somatosensory activation contralateral to the stimulation site was detected in response to spatial task and attentive task. Data Conclusion This stimulation device characterized the mapping of somatosensory representation of the whole‐body surface in individual participants during fMRI scans. Level of Evidence 2. Technical Efficacy Stage 1. J. Magn. Reson. Imaging 2020;52:1093–1101.

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