Hyperfrontality in patients with schizophrenia during saccade and antisaccade tasks: A study with fMRI
Hyperfrontality in patients with schizophrenia during saccade and antisaccade tasks: A study with fMRI
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DOI：
10.1111/j.1440-1819.2009.01941.x
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发表时间：
2009-01-01
影响因子：
11.9
通讯作者：
Matsuda, Tetsuya
中科院分区：
文献类型：
--
作者：
Fukumoto-Motoshita, Mai;Matsuura, Masato;Matsuda, Tetsuya
众所周知，精神分裂症患者的抗扫视性眼球运动（需要抑制向短暂出现的周边目标的扫视）会受到损害。先前的神经影像学研究表明，精神分裂症患者的额叶皮层和基底神经节的激活减弱。这些研究使用目标固定作为基线条件。然而，如果患者和健康受试者的基线大脑活动水平不相容，则抗眼跳相关激活的组间比较就会无效。一种可能性是，精神分裂症患者在注视过程中可能比健康受试者表现出更大的激活。为了检验这种可能性，我们在这里研究了两组在基线时不使用目标固定的情况下与反眼跳相关的大脑活动。使用箱车功能磁共振成像设计，在 18 名健康受试者和 18 名精神分裂症患者的原眼跳和反眼跳期间获取了功能性脑图像。在扫描过程中测量眼球运动。在患者组中，不再观察到背外侧前额叶皮层（DLPFC）和丘脑的活动升高（通常在反眼跳任务中相对于眼跳任务出现）。此外，在正常受试者中，抗眼跳任务期间 DLPFC 和丘脑的活动比眼跳任务期间更大。在患者中，两项任务之间没有观察到这种差异，这表明即使是注视等简单任务，这些大脑区域也可能被高度激活。特别是，患者的 DLPFC 和丘脑的激活水平与所呈现的任务的难度不相称。从这些结果来看，表明精神分裂症会导致与运动功能控制相关的额叶-纹状体-丘脑-皮质网络功能障碍。
Antisaccadic eye movements, requiring inhibition of a saccade toward a briefly appearing peripheral target, are known to be impaired in schizophrenia. Previous neuroimaging studies have indicated that patients with schizophrenia show diminished activations in the frontal cortex and basal ganglia. These studies used target fixation as a baseline condition. However, if the levels of brain activities at baseline are not compatible between patients and healthy subjects, between-group comparison on antisaccade-related activations is consequently invalidated. One possibility is that patients with schizophrenia may present with greater activation during fixation than healthy subjects. In order to examine this possibility, here we investigated brain activities associated with antisaccade in the two groups without using target fixation at baseline.Functional brain images were acquired during prosaccades and antisaccades in 18 healthy subjects and 18 schizophrenia patients using a box-car functional magnetic resonance imaging design. Eye movements were measured during scanning.In the patient group, the elevated activities in the dorsolateral prefrontal cortex (DLPFC) and thalamus, normally seen in antisaccade tasks relative to saccade tasks, were no longer observed. Moreover, in normal subjects, activities in the DLPFC and thalamus were greater during the antisaccade task than during the saccade task. In patients, no such difference was observed between the two tasks, suggesting that these brain regions are likely to be highly activated even by a simple task such as fixation. In particular, the DLPFC and thalamus in patients were not activated at a level commensurate with the difficulty of the tasks presented.From these results, it is suggested that schizophrenia entails dysfunctions in the fronto-striato-thalamo-cortical network associated with motor function control.