Developmental Ethology and Cognitive Psychology group, Centre des Sciences du Goût et de l'Alimentation, CNRS, Université Bourgogne Franche-Comté, Inra, AgroSup Dijon, F-21000, Dijon, France.
Reference Center for Rare Diseases with Psychiatric Phenotype - GénoPsy, Centre Hospitalier le Vinatier, Marc Jeannerod Institute (CNRS & Claude Bernard Lyon 1 University), Bron, France.
Transl Psychiatry. 2019 Feb 4;9(1):67. doi: 10.1038/s41398-019-0411-z.
Although various psychiatric disorders present with social-cognitive impairment, a measure assessing social-cognitive processes implicitly and reliably, with high selectivity and with enough signal-to-noise ratio (SNR) for individual evaluation of any population at any age, is lacking. Here we isolate a neural marker quantifying impaired visual coding of facial expression in individuals with 22q11.2 deletion syndrome (22q11DS) using frequency-tagging with electroencephalography (EEG). Twenty-two 22q11DS participants and 22 healthy controls were presented with changes of facial expression displayed at low, moderate, and high intensities every five cycles in a stream of one neutral face repeating 6 times per second (i.e., at a 6 Hz base rate). The brain response to expression changes tagged at the 1.2 Hz (i.e., 6 Hz/5) predefined frequency was isolated over occipito-temporal regions in both groups of participants for moderate- and high-intensity facial expressions. Neural sensitivity to facial expression was reduced by about 36% in 22q11DS, revealing impaired visual coding of emotional facial signals. The significance of the expression-change response was estimated for each single participant thanks to the high SNR of the approach. Further analyses revealed the high reliability of the response and its immunity from other neurocognitive skills. Interestingly, response magnitude was associated with the severity of positive symptoms, pointing to a potential endophenotype for psychosis risk. Overall, the present study reveals an objective, selective, reliable, and behavior-free signature of impaired visual coding of facial expression implicitly quantified from brain activity with high SNR. This novel tool opens avenues for clinical practice, providing a potential early biomarker for later psychosis onset and offering an alternative for individual assessment of social-cognitive functioning in even difficult-to-test participants.
尽管各种精神障碍都表现出社会认知障碍，但缺乏一种能够可靠、高选择性地测量社会认知过程的方法，这种方法还需要具有足够的信噪比（SNR），以便在任何年龄段的任何人群中进行个体评估。在这里，我们使用脑电图（EEG）的频率标记技术，从个体中分离出一种量化 22q11.2 缺失综合征（22q11DS）患者面部表情视觉编码受损的神经标记物。我们向 22 名 22q11DS 参与者和 22 名健康对照者展示了在一个每秒重复 6 次的中性面孔流中，以低、中、高强度每 5 个周期显示的面部表情变化。在两组参与者中，在额颞区域都可以分离出对以 1.2 Hz（即 6 Hz/5）预定义频率标记的表情变化的大脑反应，用于中高强度的面部表情。22q11DS 患者对表情变化的神经敏感性降低了约 36%，这表明他们对情绪面部信号的视觉编码受损。由于该方法的 SNR 较高，因此可以为每个单个参与者估计表情变化反应的显著性。进一步的分析显示，该反应的可靠性很高，并且不受其他神经认知技能的影响。有趣的是，反应幅度与阳性症状的严重程度相关，这表明其可能是精神病风险的潜在内表型。总的来说，本研究揭示了一种客观、选择性、可靠且无需行为的面部表情视觉编码受损的隐含量化方法，该方法从大脑活动中以高 SNR 进行定量。这种新工具为临床实践开辟了道路，为以后精神病发作提供了潜在的早期生物标志物，并为即使是难以测试的参与者的社会认知功能提供了个体评估的替代方法。
