Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02215, USA.
Schizophr Res. 2011 Oct;132(1):62-8. doi: 10.1016/j.schres.2011.07.026. Epub 2011 Aug 9.
Impaired antisaccade performance is a consistent cognitive finding in schizophrenia. Antisaccades require both response inhibition and volitional motor programming, functions that are essential to flexible responding. We investigated whether abnormal timing of hemodynamic responses (HDRs) to antisaccades might contribute to perseveration of ocular motor responses in schizophrenia. We focused on the frontal eye field (FEF), which has been implicated in the persistent effects of antisaccades on subsequent responses in healthy individuals.
Eighteen chronic, medicated schizophrenia outpatients and 15 healthy controls performed antisaccades and prosaccades during functional MRI. Finite impulse response models provided unbiased estimates of event-related HDRs. We compared groups on the peak amplitude, time-to-peak, and full-width half-max of the HDRs.
In patients, HDRs in bilateral FEF were delayed and prolonged but ultimately of similar amplitude to that of controls. These abnormalities were present for antisaccades, but not prosaccades, and were not seen in a control region. More prolonged HDRs predicted slower responses in trials that followed an antisaccade. This suggests that persistent FEF activity following an antisaccade contributes to inter-trial effects on latency.
Delayed and prolonged HDRs for antisaccades in schizophrenia suggest that the functions necessary for successful antisaccade performance take longer to implement and are more persistent. If abnormally persistent neural responses on cognitively demanding tasks are a more general feature of schizophrenia, they may contribute to response perseveration, a classic behavioral abnormality. These findings also underscore the importance of evaluating the temporal dynamics of neural activity to understand cognitive dysfunction in schizophrenia.
在精神分裂症中，反扫视任务表现受损是一种一致的认知发现。反扫视需要反应抑制和随意运动编程两种功能，这两种功能对于灵活反应至关重要。我们研究了反扫视时血液动力学反应（HDR）的异常定时是否可能导致精神分裂症患者眼动反应的持续。我们专注于额眼区（FEF），它与健康个体反扫视对后续反应的持续影响有关。
18 名慢性、药物治疗的精神分裂症门诊患者和 15 名健康对照者在功能磁共振成像期间执行反扫视和正扫视。有限脉冲响应模型提供了对事件相关 HDR 的无偏估计。我们比较了组间 HDR 的峰值幅度、到达峰值的时间和半峰全宽。
在患者中，双侧 FEF 的 HDR 延迟且延长，但最终与对照组的幅度相似。这些异常存在于反扫视中，但不存在于正扫视中，也不存在于对照区域。更长的 HDR 预测紧随反扫视的试验中反应更慢。这表明反扫视后 FEF 活动的持续存在有助于对潜伏期的试验间效应。
精神分裂症患者反扫视时的 HDR 延迟和延长表明，成功执行反扫视任务所需的功能需要更长的时间来实施，并且更持久。如果认知任务中异常持久的神经反应是精神分裂症的更普遍特征，它们可能导致反应持续，这是一种经典的行为异常。这些发现还强调了评估神经活动的时间动态以理解精神分裂症认知功能障碍的重要性。
