Assessments of prefrontal function using event-related fMRI

功能性MRI、ERP、LORETA等可以相互补充时间和空间分辨率。功能MRI与LORETA相结合是评估精神分裂症患者信息加工的一种有效方法。我们专注于两个主要系统；视觉处理系统和工作记忆系统。视觉感官输入在枕叶区通过自上而下和自下而上过程的前馈和反馈相互作用进行处理。刺激和反应之间的映射可以在前额皮质的工作记忆系统中进行管理。工作记忆系统分为中央执行系统和从属系统。实验任务和总结结果如下：前额叶皮层工作记忆系统（PFC）视觉怪范式；PFC和ACC对不常见和不规则呈现的视觉目标刺激反应不活跃/ PFC对任务无关的新奇刺激反应过度活跃；PFC目标导向反应中刺激-反应映射恶化新颖性辨别反应竞争中央执行系统退化枕叶区视觉处理系统面孔、眼睛、眼动识别枕叶区面部处理不活跃杏仁核、脑岛和枕叶外皮层眼睛和动眼过度活跃在处理面部格式塔或面部表情之前对特征细节的处理过度敏感这可能与他们人际交往能力的缺陷或各种临床表现的形成有关，比如害怕面对面的对抗或参照妄想。虚幻轮廓知觉、外皮层IC加工不活跃、前扣带和脑岛IC加工过度活跃、外皮层知觉整合缺陷；在前三个实验中，我们证实了精神分裂症患者存在工作记忆缺陷。在前三个实验中，我们证实了精神分裂症患者存在工作记忆缺陷。很可能这两个子系统都受损了。在最后的三个实验中，我们证实了视觉处理系统和工作记忆系统都受到了损害。枕叶皮层的加工缺陷可能因此增加前额叶皮层高级加工所需的负荷。奴隶系统和中央执行系统的损伤可能与视觉处理系统有关。知觉整合和自下而上加工的失败可能与脑岛和杏仁核的过度激活以及前额叶皮层的注意力分散有关。少

Functional MRI, ERP, LORETA and can complement the time and spatial resolution of each other. The combination of functional MRI and LORETA is a strong method to evaluate information processing in schizophrenia. We focused on the two main systems; visual processing system and working memory system. Visual sensory inputs are processed in occipitemporal regions through feedforwad and feedback interactions between top-down and bottom-up process. And then mapping between stimulus and responses can be governed in the working memory system in prefrontal cortex. Working memory system has subsystems, called central executive system and slave systems. Experimental tasks and summaries results of are as follows:Working memory system in prefrontal cortex (PFC)Visual oddball paradigmUnderactive in PFC and ACC for infrequently and irregularly presented visual target stimuli/Overactive for task irrelevant novel stimuli in PFC1Deteriorated stimulus-response mapping during goal-directed response for tar … More gets and distractibility to task irrelevant novel stimuliAuditory oddball paradigmFront-temporal dysfunction in passive auditory novelty discriminationResponse competition Deteriorated central executive systemVisual Processing System in Occipitemporal RegionsFace, eyes, eye-movement recognitionUnderactive in face processing in occipitemporal cortex, extrastriatel Overactive for eyes and moving-eyes in the amygdale, insula, and extrastriate cortex 1hypersensitivity in processing of feature details before processing the gestalt of the face or facial expression as a whole, which might be implicated in their deficits in interpersonal skills or forming of a variety of their clinical manifestations such as fear of eye-to-eye confrontation or delusion of reference.Illusory contour perceptionUnderactive in IC processing in extrastriateOveractive for IC in ACC and insulaDeficient in perceptual integration during processing in the extrastriate cortex, which might consequently increase the loads needed in the higher processing in the prefrontal cortexGlobal-Local perceptionUnderactive in Global processing in right occipitemporal cortexOveractive in Local processing in left occipitemporal cortex and PFCLeft hemisphere overactive-right hemisphere underactive in schizophrenic patientsIn the first three experiments, we confirmed working memory deficits in schizophrenia. It is likely that both of subsystems are impaired. In the last three experiments, we confirmed that visual processing systems are impaired as well as working memory system. Deficient processing in the occipitemporal cortex might consequently increase the loads needed in the higher processing in the prefrontal cortex. Impairments of slave system and central executive system might be related with visual processing system. Failure in perceptual integration and bottom-up processing might be implicated in overactivation in insula and amygdala and distractibility in prefrontal cortex. Less