CAREER: Model-Based fMRI of Human Object Recognition

物体识别是一项基本的认知任务，每天都要毫不费力地进行无数次，比如判断谈话对象的面部表情，在人群中寻找朋友的脸，或者阅读这篇摘要的文字。所有这些任务都依赖于视觉系统识别特定物体的能力，尽管由于光线、位置、视点或其他物体同时存在的变化，物体的外观会发生重大变化。重要的是，视觉系统不是固定的，而是可以训练用于特定任务，例如，在卫星图像中检测恐怖分子营地或在x射线电影中检测肿瘤。尽管视觉识别看起来很容易，但人们普遍认为视觉识别是一个非常困难的计算问题。从生物系统的角度来看，视觉识别涉及多个层面的理解，从计算层面，到细胞和生物物理机制的层面，再到神经元回路的层面，再到行为的层面。视觉识别的计算方法对于将来自不同实验和描述水平（如电生理学，脑成像和行为）的数据整合到一个连贯的定量框架中变得越来越重要，然后可以用于为进一步的实验提供严格的假设。马克西米利安·里森胡伯博士获得了美国国家科学基金会颁发的终身成就奖，他正在继续研究大脑皮层物体识别的计算模型。他正在应用这个模型来研究视觉经验和特定任务的训练如何塑造大脑对外部世界的表征及其物体识别能力，以及视觉系统如何在存在干扰刺激的情况下成功识别物体。特别是，该模型被用于提供关于特定物体识别任务（从新刺激的辨别到视觉混乱中的分类和物体识别）的训练如何改变视觉系统不同层次的处理的详细假设，以及这些变化如何与行为表现的改善相关。这导致了一系列假设，这些假设将在人类志愿者身上进行一系列行为和脑成像实验，使用与模拟中相同的刺激和任务。重要的是，模拟和实验是紧密结合的，这样简单任务的实验结果可以用来完善模型，然后可以用来为更复杂的任务提供更具体的假设。这项研究的结果将与人工智能中机器视觉系统的设计相关，该系统可以更好地模仿人类的视觉方式，用于人机界面的开发，以最佳地利用大脑处理视觉信息的能力，以及涉及从行李检查到卫星图像分析等对象识别任务的人类训练应用。了解典型大脑中涉及物体识别的神经回路对于理解和最终治疗神经疾病（如自闭症、精神分裂症和阅读障碍）中的物体识别缺陷也很重要。CAREER奖的一个关键因素是，Riesenhuber博士计划通过开发综合认知神经科学的基于模型的课程，将构成研究工作基础的计算模型作为教育工具。

Object recognition is a fundamental cognitive task that is performed effortlessly countless times every day, such as when gauging a conversation partner's facial expression, looking for a friend's face in a crowd, or reading the words of this abstract. All these tasks depend on the visual system's ability to recognize specific objects, despite significant variations in their appearance due to changes in lighting, position, viewpoint, or the simultaneous presence of other objects. Importantly, the visual system is not hard-wired but can be trained for specific tasks, e.g., detecting terrorist camps in satellite images or tumors in X-ray films. Despite the apparent ease with which we see, visual recognition is widely acknowledged to be a very difficult computational problem. From a biological systems perspective, visual recognition involves several levels of understanding, from the computational level, to the levels of cellular and biophysical mechanisms and the level of neuronal circuits, up to the level of behavior. Computational approaches to visual recognition are becoming increasingly important to integrate data from different experiments and levels of description (such as electrophysiology, brain imaging, and behavior) into one coherent, quantitative framework that can then be used to provide rigorous hypotheses for further experiments. With a CAREER award from the National Science Foundation, Dr. Maximilian Riesenhuber is continuing his work on a computational model of object recognition in cortex. He is applying this model to study how visual experience and training on specific tasks shape the brain's representation of the external world and its object recognition capabilities, and how the visual system can successfully recognize objects, even in the presence of interfering stimuli. In particular, the model is being used to provide detailed hypotheses on how training on specific object recognition tasks (ranging from the discrimination of novel stimuli to categorization and object recognition in visual clutter) can modify processing at different levels of the visual system, and how these changes are related to improvements in behavioral performance. This leads to a set of hypotheses that are to be tested with human volunteers in a series of behavioral and brain imaging experiment, using the same stimuli and tasks as in the simulations. Importantly, simulations and experiments are tightly integrated so that experimental results from simpler tasks can be used to refine the model, which can then be used to provide more specific hypotheses for more complex tasks.The results of this research will be relevant for the design of machine vision systems in artificial intelligence that better mimic how humans see, for the development of human-machine interfaces that optimally leverage the brain's ability to process visual information, and for applications involving human training on object recognition tasks ranging from baggage screening to satellite image analysis. Understanding the neural circuitry involved in object recognition in the typical brain is also important for understanding and ultimately treating object recognition deficits in neural disorders such as autism, schizophrenia, and dyslexia. A key element of the CAREER award is Dr. Riesenhuber's plan to use the same computational model that forms the basis of the research effort as an educational tool by developing a model-based curriculum in integrative cognitive neuroscience.