Valdez André B, Papesh Megan H, Treiman David M, Goldinger Stephen D, Steinmetz Peter N
Neurtex Brain Research Institute, 8300 Douglas, Suite 800, Dallas, TX 75225, USA.
Department of Psychology, New Mexico State University, Las Cruces, NM 88003, USA.
NeuroSci. 2022 Aug 5;3(3):419-439. doi: 10.3390/neurosci3030031. eCollection 2022 Sep.
Previous research has suggested that race-specific features are automatically processed during face perception, often with out-group faces treated categorically. Functional imaging has illuminated the hemodynamic correlates of this process, with fewer studies examining single-neuron responses. In the present experiment, epilepsy patients undergoing microwire recordings in preparation for surgical treatment were shown realistic computer-generated human faces, which they classified according to the emotional expression shown. Racial categories of the stimulus faces varied independently of the emotion shown, being irrelevant to the patients' primary task. Nevertheless, we observed race-driven changes in neural firing rates in the amygdala, anterior cingulate cortex, and hippocampus. These responses were broadly distributed, with the firing rates of 28% of recorded neurons in the amygdala and 45% in the anterior cingulate cortex predicting one or more racial categories. Nearly equal proportions of neurons responded to White and Black faces (24% vs. 22% in the amygdala and 26% vs. 28% in the anterior cingulate cortex). A smaller fraction (12%) of race-responsive neurons in the hippocampus predicted only White faces. Our results imply a distributed representation of race in brain areas involved in affective judgments, decision making, and memory. They also support the hypothesis that race-specific cues are perceptually coded even when those cues are task-irrelevant.
先前的研究表明，在面部感知过程中，特定种族特征会被自动处理，通常对外群体面孔进行分类处理。功能成像揭示了这一过程的血液动力学相关性，而较少有研究考察单神经元反应。在本实验中，为准备手术治疗而接受微丝记录的癫痫患者观看了逼真的计算机生成的人脸，并根据所显示的情感表达对面孔进行分类。刺激面孔的种族类别与所显示的情感无关，与患者的主要任务无关。然而，我们观察到杏仁核、前扣带回皮质和海马体中神经放电率存在种族驱动的变化。这些反应分布广泛，杏仁核中28%的记录神经元和前扣带回皮质中45%的记录神经元的放电率可预测一个或多个种族类别。对白人面孔和黑人面孔做出反应的神经元比例几乎相等（杏仁核中分别为24%和22%，前扣带回皮质中分别为26%和28%）。海马体中较小比例（12%）的种族反应神经元仅对白人脸孔做出预测。我们的结果表明，在涉及情感判断、决策和记忆的脑区中，种族存在分布式表征。它们还支持这样一种假设，即即使这些线索与任务无关，特定种族线索也会在感知上被编码。
