Centre for Addiction and Mental Health, Toronto, ON, Canada.
Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.
Transl Psychiatry. 2022 Aug 10;12(1):325. doi: 10.1038/s41398-022-02099-2.
In individuals with body dysmorphic disorder (BDD), perceptual appearance distortions may be related to selective attention biases and aberrant visual scanning, contributing to imbalances in global vs. detailed visual processing. Treatments for the core symptom of perceptual distortions are underexplored in BDD; yet understanding their mechanistic effects on brain function is critical for rational treatment development. This study tested a behavioral strategy of visual-attention modification on visual system brain connectivity and eye behaviors. We acquired fMRI data in 37 unmedicated adults with BDD and 30 healthy controls. Participants viewed their faces naturalistically (naturalistic viewing), and holding their gaze on the image center (modulated viewing), monitored with an eye-tracking camera. We analyzed dynamic effective connectivity and visual fixation duration. Modulated viewing resulted in longer mean visual fixation duration compared to during naturalistic viewing, across groups. Further, modulated viewing resulted in stronger connectivity from occipital to parietal dorsal visual stream regions, also evident during the subsequent naturalistic viewing, compared with the initial naturalistic viewing, in BDD. Longer fixation duration was associated with a trend for stronger connectivity during modulated viewing. Those with more severe BDD symptoms had weaker dorsal visual stream connectivity during naturalistic viewing, and those with more negative appearance evaluations had weaker connectivity during modulated viewing. In sum, holding a constant gaze on a non-concerning area of one's face may confer increased communication in the occipital/parietal dorsal visual stream, facilitating global/holistic visual processing. This effect shows persistence during subsequent naturalistic viewing. Results have implications for perceptual retraining treatment designs.
在躯体变形障碍（BDD）患者中，感知外观扭曲可能与选择性注意偏差和异常视觉扫描有关，导致整体与详细视觉处理之间的不平衡。BDD 中对感知扭曲的核心症状的治疗方法尚未得到充分探索；然而，了解其对大脑功能的机制影响对于合理的治疗发展至关重要。本研究测试了一种视觉注意力修正的行为策略对视觉系统大脑连接和眼动行为的影响。我们在 37 名未接受药物治疗的 BDD 患者和 30 名健康对照者中获取了 fMRI 数据。参与者自然地观看自己的面孔（自然观看），并通过眼动追踪相机注视图像中心（调制观看）。我们分析了动态有效连接和视觉注视持续时间。与自然观看相比，调制观看导致所有参与者的平均视觉注视持续时间更长。此外，与初始自然观看相比，调制观看导致枕叶到顶叶背侧视觉流区域的连接更强，这在随后的自然观看中也很明显，BDD 患者也是如此。在调制观看期间，更长的注视时间与更强的连接呈趋势相关。BDD 症状更严重的患者在自然观看期间背侧视觉流连接较弱，而对外貌评价更消极的患者在调制观看期间连接较弱。总之，将目光固定在自己面部的一个非关注区域上，可能会增加枕叶/顶叶背侧视觉流中的信息交流，从而促进整体/整体视觉处理。这种影响在随后的自然观看中持续存在。研究结果对感知再训练治疗设计具有启示意义。
