Causal Connections of the cortical face network studied with TMS and fMRI

无论是第一次见到一个人，还是见到一个我们认识了一辈子的人，我们都会通过看他们的脸来了解他的心情和意图。这种理解不仅由她或他做出的语言和非语言暗示形成，还取决于他们的脸的大小和形状，以及他们如何移动头部、眼睛和嘴巴。我们的大脑效率如此之高，对我们来说，即时处理这些与社会相关的信息似乎毫不费力。然而，即使是最简单的功能，比如识别某人的身份或面部表情，也需要分布在大脑各处的专门的面部选择区域的相互作用。虽然这些区域的位置已经确定，但这只是理解我们如何识别人脸的第一步。目前，我们还不能真正理解，当我们认出一位朋友时，脸部选择区域是如何相互作用的，或者这位朋友根据他们的面部表情感觉如何。需要新的实验范式来暂时和安全地扰乱大脑功能，从而因果地展示面孔选择区域如何相互作用，以及如何与处理不同认知功能(如情绪和记忆)的大脑区域一起工作。以这种方式研究干扰的影响将有助于我们更好地了解大脑损伤和大脑疾病(例如自闭症)如何影响人类行为。本提案中的实验使用经颅磁刺激(TMS)、功能磁共振成像(FMRI)和神经心理学的新组合来解决这个问题。TMS可以暂时且安全地干扰目标大脑区域，当与功能磁共振相结合时，它为因果研究大脑网络的认知功能提供了一个强大的实验工具。对患有TMS的神经学正常参与者的大脑进行短暂干扰，并用行为和功能磁共振成像测量这种干扰的影响，是一种安全且可复制的方法，可以建立在200多年的神经心理学研究的基础上。我们将使用TMS来干扰与社会知觉有关的大脑区域，如处理面部表情和语音的区域，并测量这对大脑有什么影响。这些研究的结果将被用来生成人脸处理网络因果功能连接的详细地图。这些功能联系的行为相关性也将在TMS行为实验和对面孔识别缺陷患者的神经心理学研究中进行测试，以进一步确定干扰如何影响面孔处理行为。然后，在项目的最后阶段，我们将对所有获得的TMS/fMRI、TMS和神经心理学数据进行荟萃分析，以产生一个新的人脸处理网络的因果模型。面孔处理网络的连接和认知操作的新因果模型很重要，因为它将更好地描述复杂的认知功能是如何在多个大脑区域进行处理的。这一模式也将具有临床意义。患有自闭症和精神分裂症等大脑障碍的人表现出异常的面部处理能力。绘制面部处理网络的功能连接图将加强对这些社会性大脑疾病中大脑连接如何受损的理解。例如，通过确定社会障碍的目标节点，如面部选择性STS区域，以供未来研究和可能的治疗。

Whether meeting someone for the first time, or seeing someone we have known all our lives, we will understand the mood and intentions of that person by looking at their face. This understanding is formed not only by the verbal and non-verbal cues that she or he makes but also by the size and shape of their face and by how they move their head, eyes and mouth. Our brains are so efficient that, to us, instantly processing this wealth of socially relevant information appears to happen effortlessly. Yet even the simplest function, like recognizing someone's identity, or their facial expression, requires the interaction of specialized face-selective regions distributed across the brain. While the locations of these regions have been established this is only the first step in understanding how we recognize faces. We currently lack any real comprehension of how face-selective regions interact with each other when we recognize a friend, or how that friend feels based on their facial expression. New experimental paradigms are required that will transiently, and safely, disrupt brain function, to causally demonstrate how face-selective regions operate with each other and with brain regions that process different cognitive functions such as emotion and memory. Studying the effects of disruption in this manner will help us to better understand how brain damage and brain disorders (e.g. autism) can impact human behaviour.The experiments in this proposal address this issue using a novel combination of transcranial magnetic stimulation (TMS), functional magnetic resonance imaging (fMRI) and neuropsychology. TMS can transiently, and safely, disrupt a targeted brain region and, when combined with fMRI, it offers a powerful experimental tool for causally studying the cognitive functions of brain networks. Transiently disrupting the brains of neurologically normal participants with TMS and measuring the effects of this disruption with behaviour and fMRI is a safe and replicable way to build on more than two hundred years of neuropsychological research.We will use TMS to disrupt brain regions implicated in social perception, such as those that process facial expression and speech, and measure what impact this has on the brain. The results of these studies will be used to generate detailed maps of the causal functional connectivity of the face-processing network. The behavioural relevance of these functional connections will also be tested in behavioural TMS experiments and neuropsychological studies of a patient with face recognition deficits, to further establish how disruption impacts face-processing behaviour. Then, in the final stages of the project, we will perform a meta-analysis of all acquired combined TMS/fMRI, TMS and neuropsychological data to produce a new causal model of the face-processing network. A new causal model of the connections and cognitive operations of the face-processing network is important because it will give us a better description of how complex cognitive functions are processed across multiple brain regions. This model will also have clinical relevance. Abnormal face-processing performance has been shown in individuals with brain disorders, such as autism and schizophrenia. Mapping the functional connections of the face-processing network will enhance understanding of how brain connectivity can be impaired in these social brain disorders. For example, by identifying target nodes in social disorders, such as the face-selective STS region, for future study and possible treatment.