Iwabuchi S J, Palaniyappan L
Translational Neuroimaging for Mental Health,Division of Psychiatry and Applied Psychology,University of Nottingham,Nottingham,UK.
Departments of Psychiatry & Medical Biophysics,University of Western Ontario,London,Ontario,Canada.
Psychol Med. 2017 May;47(7):1300-1310. doi: 10.1017/S0033291716003469. Epub 2017 Jan 12.
Sensory-processing deficits appear crucial to the clinical expression of symptoms of schizophrenia. The visual cortex displays both dysconnectivity and aberrant spontaneous activity in patients with persistent symptoms and cognitive deficits. In this paper, we examine visual cortex in the context of the remerging notion of thalamic dysfunction in schizophrenia. We examined specific regional and longer-range abnormalities in sensory and thalamic circuits in schizophrenia, and whether these patterns are strong enough to discriminate symptomatic patients from controls.
Using publicly available resting fMRI data of 71 controls and 62 schizophrenia patients, we derived conjunction maps of regional homogeneity (ReHo) and fractional amplitude of low-frequency fluctuations (fALFF) to inform further seed-based Granger causality analysis (GCA) to study effective connectivity patterns. ReHo, fALFF and GCA maps were entered into a multiple kernel learning classifier, to determine whether patterns of local and effective connectivity can differentiate controls from patients.
Visual cortex shows both ReHo and fALFF reductions in patients. Visuothalamic effective connectivity in patients was significantly reduced. Local connectivity (ReHo) patterns discriminated patients from controls with the highest level of accuracy of 80.32%.
Both the inflow and outflow of Granger causal information between visual cortex and thalamus is affected in schizophrenia; this occurs in conjunction with highly discriminatory but localized dysconnectivity and reduced neural activity within the visual cortex. This may explain the visual-processing deficits that are present despite symptomatic remission in schizophrenia.
感觉处理缺陷似乎对精神分裂症症状的临床表达至关重要。在有持续性症状和认知缺陷的患者中，视觉皮层表现出连接障碍和异常的自发活动。在本文中，我们在精神分裂症丘脑功能障碍这一重新出现的概念背景下研究视觉皮层。我们检查了精神分裂症患者感觉和丘脑回路中特定的区域及长程异常，以及这些模式是否强大到足以将有症状的患者与对照组区分开来。
利用71名对照者和62名精神分裂症患者公开可用的静息态功能磁共振成像数据，我们得出了局部一致性（ReHo）和低频波动分数振幅（fALFF）的联合图谱，以指导进一步基于种子点的格兰杰因果分析（GCA）来研究有效连接模式。将ReHo、fALFF和GCA图谱输入多核学习分类器，以确定局部和有效连接模式是否能区分对照组和患者。
患者的视觉皮层显示ReHo和fALFF均降低。患者的视丘有效连接显著降低。局部连接（ReHo）模式以80.32%的最高准确率区分患者和对照组。
精神分裂症患者视觉皮层和丘脑之间格兰杰因果信息的流入和流出均受到影响；这与高度有区分性但局部的连接障碍以及视觉皮层内神经活动减少同时发生。这可能解释了精神分裂症患者即使症状缓解仍存在的视觉处理缺陷。
