Perceptual Modulation of Microcircuit Dynamics Across Cortical Face Patches

描述(申请人提供)：我们的视觉系统是在自然环境中进化的，有理由认为它是为了更好地识别一组特定的生态相关物体而设计的。面孔感知是向我们传达身份、性别和情绪信息的一项基本技能，这些信息在社会和情感互动中是有用的。最近有研究表明，人类和猕猴共用大部分的大脑皮层脸部处理机制。在这种背景下，本项目的总体目的是剖析参与人脸刺激多特征检测的神经机制，并测试该系统在人脸有意识和无意识可见性过程中是否发挥作用。支持这一普遍用途的概念和方法框架基于一个新颖的实验平台，该平台包括耦合功能磁共振成像以功能定位面部选择性皮质斑块，以及多电极/刺激技术以记录每个斑块内的特定细胞属性并测试猕猴的因果关系。第一个目标将致力于表征面部贴片上信息流的调整专门化和方向性。选择性的出现将通过分析偏爱和反偏爱的面部空间来研究局部皮质抑制是否起作用。一旦完成了第一步，将使用干扰技术来测量神经对人工刺激和自然视觉刺激的反应。第二组实验将评估神经信号(单个单位和LFP)与检测任务中的行为反应之间的相关性和因果联系。一旦系统模型被初步确定，这个项目的最后部分将确定意识和无意识人脸识别的神经特征。知觉可见性操纵将使用对象替代掩蔽实现，这是一种在人类中广泛使用的精神医学范式，允许系统地控制感知到的刺激。我假设视觉信息可以前馈的方式到达斑块系统的早期节点，即使在接近阈值的视觉刺激呈现时也建立了选择性，并且这种模式可以从感知中分离出来，这需要反馈机制。这些相互关联的方法使用人脸斑块系统作为视觉对象识别的专门模型，提高了揭示调节视觉对象感知的内部工作的新信息的可能性。

DESCRIPTION (provided by applicant): Our visual system evolved in a natural environment, and is reasonable to assume that it has been sculpted to be better at recognizing a definite ecological relevant set of objects. Face perception is an essential feat that conveys to us information about identity, gender, and mood which is useful in social and emotional interactions. It has been recently suggested that humans and macaques share most of the cortical face processing machinery. In this vein, the general purpose of this project is to dissect the neural mechanisms participating in detection of multiple features of face stimuli, and test if the system plays a role during conscious and unconscious visibility of faces. The conceptual and methodological framework supporting this general purpose is grounded on a novel experimental platform consisting in coupling fMRI to functionally map face-selective cortical patches and multielectrode/stimulation techniques to record specific cell properties within each patch and test for causal relationships in macaque monkeys. The first aim will pursue to characterize tuning specialization and directionality of information flow across face patches. Emergence of selectivity will be examined analyzing preferred and anti-preferred face spaces to investigate if local cortical inhibition plays a role. Once this first step is achieved, interference techniques to measure neural responses to artificial stimulation and to natural visual stimulation will be used. The second set of experiments will evaluate the correlation and causal link between neural signals (single unit and LFP) and behavioral responses in a detection task. Once the system model has been initially characterized, the final part of this project will determine the neural signature of conscious and unconscious face recognition. Perceptual visibility manipulations will be achieved using an object-substitution masking, a widely used psychopysical paradigm in humans that permit a systematic control of the perceived stimulus. I hypothesize that visual information can reach early nodes of the patch system in a feedforward fashion, building up selectivity even at near-threshold visual stimuli presentations, and that this mode can be dissociated from perceptual awareness, which requires feedback mechanisms. These interrelated approaches using the face patch system as a specialized model for visual object recognition enhances the probability of revealing novel information of the inner workings mediating visual object perception.