Parallel distributed processing neuroimaging in schizophrenic patients during the frontal tasks

采用空间滤波脑磁图(MEG)分析方法，以50ms为单位，以200ms为时间窗，对有/无幻听精神分裂症患者和正常对照受试者在Stroop任务和词汇生成任务中神经激活的并行分布处理进行了研究。在25-60赫兹频段，在每个时间窗检查显示电流源密度(CSD)显著变化的皮质区域。三组均表现出明显的CSD降低，与神经激活相对应，且沿基本认知信息处理流程的时间重叠：感觉输入系统-执行控制系统-运动输出系统，时间潜伏期分别为300ms、350ms、450ms。背外侧前额叶皮质(DLPFC)的一过性神经激活为双侧激活，正常对照组为左侧激活，非幻觉者为左侧激活，幻觉者为右侧激活。我们的结果表明，在Stroop任务中，精神分裂症患者左侧DLPFC的功能障碍与幻听有关，而信息加工流程没有受到影响；在词汇生成任务中，没有患者在后颞叶上回表现出激活，而几乎所有的正常受试者都表现出激活，提示Wernicke区周围的自我监控功能障碍。有幻听的患者无一例出现额下回激活，而无幻听的患者未见激活，提示Broca区周围内语言功能障碍。这些时间高分辨率的神经影像可能有助于开发利用重复经颅磁刺激的新疗法或选择高危对象进行早期干预。

Using a spatially filtered magnetoencephalography(MEG) analysis, SAM(synthetic aperture magnetometry), we estimated parallel distributed processing of the neural activations in the Stroop task and in the words generation task for schizophrenic patients with/without auditory hallucinations and for normal control subjects.In the Stroop task, one hundred unaveraged MEG signals from the presentation of incongruent stimulus to responses were analyzed with a time window of 200 ms in steps of 50 ms. In the 25-60 Hz band, cortical regions that showed significant current source density(CSD) changes were examined for each time window. The three groups showed significantly decreased CSD, corresponding to neural activation, with temporal overlap along the fundamental cognitive information processing flow : sensory input system-executive control system-motor output system with 300ms, 350ms, 450ms time latency respectively. Transient neural activations in the dorsolateral prefrontal cortex(DLPFC) were bilateral with left-side dominancy for the normal controls, left-lateralized for the non-hallucinators and right-lateralized for the hallucinators. Our results suggest that the dysfunction in the left DLPFC was related to auditory hallucinations, while the information processing flow was unaffected in the schizophrenic subjects in the Stroop task.In the words generation task, no patients showed activation in the post superior temporal gyrus, while almost all normal subjects showed it, suggesting the dysfunction of self-monitoring around the Wernicke area. No patients with auditory hallucination showed activation in the post inferior frontal gyrus, while patients without auditory hallucination did not show it, suggesting the dysfunction in the inner-speech around the Broca area.These time high resolution neuroimages might contribute the developing a new treatment using repetitive transcranial magnetic stimulation or the selection of high risk subjects for the early intervention.