Department of Psychological and Brain Sciences, Texas A&M University, College Station, Texas, USA.
Psychophysiology. 2018 May;55(5):e13024. doi: 10.1111/psyp.13024. Epub 2017 Oct 26.
There are many advantages to human beings' ability to generate and sustain mental imagery in the absence of exteroceptive stimuli; however, this ability may also underlie emotional disorders characterized by worry, rumination, or excessive concern about the future. For instance, fear-based disorders may be characterized by heightened ERPs to negative imagery. On the other hand, distress disorders may be characterized by attempts to avoid engaging with negative mental imagery, and therefore reduced electrocortical response. Prior ERP work has used negative and neutral pictorial stimuli to establish the parameters of response in healthy individuals, before taking these paradigms to clinical samples to assess aberrant emotion processing. Yet despite its clinical relevance, no study to date has elicited a late positive potential (LPP), a robust measure of emotion processing, to standardized negative imagined scenes. Here, participants listened to audio descriptions of negative and neutral scenes, and were asked to imagine these scenes as vividly as possible. Results showed that negative imagined scenes elicited an increased LPP, lasting approximately 10 s after audio description offset, as well as heightened ratings of arousal and unpleasantness. Moreover, participants with greater self-reported cognitive concerns about uncertain future events (higher prospective intolerance of uncertainty) showed reduced emotional modulation of the LPP. These data provide the first evidence of sustained electrocortical processing of standardized negative imagery elicited in the absence of salient visual cues, and suggest that cognitive risk for anxiety in an unselected sample may be represented phenotypically by blunted LPPs to negative imagery.
人类在没有外部刺激的情况下产生和维持心理意象的能力有很多优势；然而，这种能力也可能是以下述情绪障碍为基础的，这些障碍的特点是担心、沉思或过度关注未来。例如，基于恐惧的障碍可能表现为对负面意象的 ERP 增强。另一方面，痛苦障碍可能表现为试图避免接触负面心理意象，因此皮质电反应减少。先前的 ERP 研究使用负面和中性图像刺激来建立健康个体反应的参数，然后将这些范式应用于临床样本，以评估异常的情绪处理。然而，尽管它具有临床相关性，但迄今为止，没有研究激发了晚期正电位 (LPP)，这是一种衡量情绪处理的有力指标，以标准化的负面想象场景。在这里，参与者听取了负面和中性场景的音频描述，并被要求尽可能生动地想象这些场景。结果表明，负面想象场景引发了 LPP 的增加，大约在音频描述结束后 10 秒持续，并且唤醒和不愉快的评分也增加了。此外，自我报告对未来不确定事件的认知担忧程度较高（对未来不确定性的前瞻性耐受性较高）的参与者表现出 LPP 的情绪调节减少。这些数据首次提供了在没有明显视觉线索的情况下，标准化负面图像诱发的持续皮质电处理的证据，并表明在未选择的样本中，焦虑的认知风险可能表现在对负面图像的 LPP 迟钝上。
