Maher Stephen, Ekstrom Tor, Holt Daphne, Ongur Dost, Chen Yue
McLean Hospital, Department of Psychiatry, Harvard Medical School, Belmont, MA;
Massachusetts General Hospital, Department of Psychiatry, Harvard Medical School, Boston, MA.
Schizophr Bull. 2016 May;42(3):666-74. doi: 10.1093/schbul/sbv140. Epub 2015 Oct 9.
Face perception impairment in schizophrenia has long been recognized. However, brain mechanisms underlying this socially important perceptual deficit are not well understood. Previous magnetic resonance imaging (MRI) studies have shown that patients have altered structure in brain regions responsible for processing face information, but functional properties of these brain regions are not clearly determined. A key functional property of the face-processing system--face selectivity--has yet to be evaluated in schizophrenia.
We used functional MRI (fMRI) to examine face selectivity of 3 core face-processing regions--fusiform face area (FFA), occipital face area (OFA), and superior temporal sulcus (STS)--in schizophrenia patients (n = 24) and healthy controls (n = 23). To disassociate face-specific processing from general perceptual processing, we compared cortical activations during performance of perceptually equated face and tree detection tasks.
Activation levels of the 3 putative face-processing regions during face detection did not differ between patients and controls, being similar for FFA and OFA and absent for STS. However, face selectivity, indexed by the difference in cortical activation between face and tree detection, was significantly reduced in patients for FFA, especially for low-contrast stimuli. FFA activation and perceptual performance during face detection were associated in patients.
These results show a lack of face-specific processing in the schizophrenic brain region presumably subserving face perception. This finding suggests boosting visual salience of face images as a potential therapeutic venue for improving face perception in this psychiatric disorder.
精神分裂症患者的面部感知障碍早已被认识到。然而,这种具有社会重要性的感知缺陷背后的脑机制尚未得到充分理解。以往的磁共振成像(MRI)研究表明,患者负责处理面部信息的脑区结构发生了改变,但这些脑区的功能特性尚未明确确定。面部处理系统的一个关键功能特性——面部选择性——在精神分裂症中尚未得到评估。
我们使用功能磁共振成像(fMRI)来检查24例精神分裂症患者和23名健康对照者的3个核心面部处理区域——梭状面孔区(FFA)、枕叶面孔区(OFA)和颞上沟(STS)的面部选择性。为了将面部特异性处理与一般感知处理区分开来,我们比较了在感知等效的面部和树木检测任务执行过程中的皮层激活情况。
在面部检测过程中,3个假定的面部处理区域的激活水平在患者和对照者之间没有差异,FFA和OFA相似,STS没有激活。然而,以面部和树木检测之间的皮层激活差异为指标的面部选择性,在患者的FFA中显著降低,尤其是对于低对比度刺激。患者在面部检测过程中的FFA激活与感知表现相关。
这些结果表明,在可能参与面部感知的精神分裂症脑区中缺乏面部特异性处理。这一发现表明,提高面部图像的视觉显著性作为改善这种精神疾病中面部感知的潜在治疗途径。