Using steady-state visual evoked potentials (SSVEP) to measure brain responses to faces and objects

这项拟议的研究使用稳态视觉诱发电位(SSVEP)来研究人脸和物体感知的神经关联。已有研究表明，对人类视觉系统的重复刺激会在脑电(EEG)中产生与重复刺激-SSVEP频率相似的振荡(Regan 2009)。所提出的实验将采用适应范例，在该范例中，以周期性的呈现速率(4赫兹)在屏幕上重复闪现相同身份的适应面孔(例如，“Joe”)。基于先前的一项研究(Rossion&Boremanse，2011)，连续呈现相同的面孔身份会导致神经信号的减少(即重复抑制效应)。在测试阶段，不同身份的人脸(例如，“Fred”、“Bob”、“Bill”等)以用于适应的刺激率来表示。不同面孔的呈现会导致脑电信号的突然增加，这表明SSVEP对个体面孔身份的变化很敏感。SSVEP技术与传统的事件相关电位(ERPs)相比的优势在于，该方法产生了高信噪比，需要的实验次数大大减少，并且是一种稳健的高水平视觉知觉分辨措施。**然而，SSVEP是否对知觉经验和学习的影响做出反应尚不清楚。在当前的提案中，通过测试真实世界和受过实验室培训的专家来解决这些问题。在第一系列实验中，对鸟类有丰富经验的真实世界鸟类专家和拥有丰富经验的单一种族的人将被研究--而不是其他种族的面孔。我们假设，鸟类专家和自己种族面孔专家在专业领域(即鸟类专家的鸟类，自己种族专家的自己种族面孔)对刺激的SSVEP将比新手表现出更大的SSVEP。此外，SSVEP的差异将与专业领域对对象和人脸的识别差异相关。第二，我们将调查在实验室中获得知觉专业知识的培训研究。我们预测，决定知觉专长并调节SSVEP信号强度的是那种知觉经验，而不是多少知觉经验。在最后一组实验中，我们将检验SSVEP的大小是否区分了面部识别的个体差异以及神经典型人群和已知面部识别缺陷人群(即自闭症患者)之间的组间差异。总而言之，拟议的研究计划填补了我们对引导高级视觉过程的机制的理解的关键空白，将观察者的感知经验和能力与大脑活动的差异联系起来。

The proposed research investigates the neural correlates of human face and object perception using steady-state visual-evoked potentials (SSVEP). It has been shown that repetitive stimulation of the human visual system produces oscillations in the electroencephalogram (EEG) that mimics the frequency of the repeating stimulus - the SSVEP (Regan 2009). The proposed experiments will employ an adaptation paradigm in which an adapting face of the same identity (e.g., "Joe") is repeatedly flashed on the screen at a periodic rate of presentation (4 Hz). Based on a previous study (Rossion & Boremanse, 2011), the continuous presentation of the same face identity produces a reduction in the neural signal (i.e., repetition suppression effect). In the test phase, faces of different identities (e.g., "Fred", "Bob", "Bill", etc.) are shown at the rate of stimulation used for adaptation. The presentation of different faces cause an abrupt increase in the EEG signal indicating that the SSVEP is sensitive to the changing identities of individual faces. The advantages of the SSVEP technique over traditional event-related potentials (ERPs) are that the method yields a high signal-to-noise ratio, requires substantially fewer experimental trials and is a robust measure of perceptual discrimination in high-level vision.**However, it is not known if the SSVEP is responsive to the effects of perceptual experience and learning. These questions are addressed in the current proposal by testing real world and laboratory-trained experts. In the first series of experiments, real world bird experts who have extensive experience to birds and mono-racial people who have extensive experience to own-, but not other-race faces will be studied. We hypothesize that bird experts and own-race face experts will exhibit a greater SSVEP to stimuli in the domain of expertise (i.e., birds for bird experts, own-race faces for own-race experts) than novices. Moreover, SSVEP differences will be correlated with differences in recognition of objects and faces from the domain of expertise. Second, we will investigate the acquisition of perceptual expertise in a laboratory training studies. We predict that it is the kind, not the amount of perceptual experience that determines perceptual expertise and modulates the strength of the SSVEP signal. In the final set of experiments, we will examine whether the magnitude of the SSVEP distinguishes individual differences in face recognition and inter-group differences between neurotypical people and a population with known face recognition deficits (i.e., people on the autism spectrum). In summary, the proposed program of research fills a critical gap in our understanding of mechanisms that guide the processes of high-level vision, linking the observer's perceptual experience and abilities with differences in brain activity.