Department of Psychology, Michigan State University, East Lansing, MI, USA; Division of Psychiatry and Behavioral Medicine, Michigan State University, East Lansing, MI, USA.
Department of Psychology, Michigan State University, East Lansing, MI, USA.
Int J Psychophysiol. 2018 Jun;128:111-118. doi: 10.1016/j.ijpsycho.2018.03.012. Epub 2018 Mar 21.
Impairments in cognitive control-the ability to exert control over thoughts and actions and respond flexibly to the environment-are well-documented in schizophrenia. However, the degree to which experimental task performance reflects true cognitive control impairments or more general alterations in effort, arousal and/or task preparedness is unclear. Pupillary responses can provide insight into these latter factors, as the pupil dilates with degree of cognitive effort and response preparation. In the current study, 16 medicated outpatients with schizophrenia (SZP) and 18 healthy controls performed a task that measures the ability to reactively inhibit and modify a planned action-the double-step task. In this task, participants were required to make a saccade to a visual target. Infrequently, the target jumped to a new location and participants were instructed to rapidly inhibit and change their eye movement plan. Applying a race model of performance, we have previously shown that SZP require more time to inhibit a planned action. In the current analysis, we measured pupil dilation associated with task preparation and found that SZP had a shallower increase in pupil size prior to the onset of the trial. Additionally, reduced magnitude of the pupil response was associated with negative symptom severity in patients. Based on primate neurophysiology and cognitive neuroscience work, we suggest that this blunted pupillary response may reflect abnormalities in a general orienting response or reduced motivational significance of a cue signifying the onset of a preparatory period and that these abnormalities might share an autonomic basis with negative symptoms.
认知控制损伤——即对思维和行为进行控制并灵活应对环境的能力——在精神分裂症中已有充分记录。然而，实验任务表现程度反映了真正的认知控制损伤还是更普遍的努力、唤醒和/或任务准备的改变尚不清楚。瞳孔反应可以提供对这些因素的深入了解，因为瞳孔会随着认知努力和反应准备的程度而扩大。在当前的研究中，16 名接受药物治疗的精神分裂症门诊患者（SZP）和 18 名健康对照者进行了一项任务，该任务可衡量反应性抑制和修改计划动作的能力-双步任务。在这个任务中，参与者被要求进行扫视到一个视觉目标。目标很少跳到新的位置，参与者被指示快速抑制并改变他们的眼球运动计划。通过应用性能的竞赛模型，我们之前已经表明 SZP 需要更多的时间来抑制计划的动作。在当前的分析中，我们测量了与任务准备相关的瞳孔扩张，发现 SZP 在试验开始前瞳孔大小的增加幅度较小。此外，患者的负性症状严重程度与瞳孔反应幅度的降低有关。基于灵长类动物神经生理学和认知神经科学的工作，我们认为这种迟钝的瞳孔反应可能反映了一般定向反应的异常或表示准备期开始的提示的动机意义降低，并且这些异常可能与负性症状具有自主基础。
