Representation of Object Information in the Primate Visual System

人类有一种惊人的能力，可以从视觉上识别几乎无限数量的物体，并将它们分类，如面孔、汽车或房屋。尽管由于距离、视角、光照等环境因素，物体的外观存在巨大的可变性，但我们仍然能够实现这一壮举。在美国国家科学基金会的资助下，普林斯顿大学的Sabine Kastner博士正在研究认知神经科学领域的一个主要领域，即有效视觉识别的神经机制。长期以来，人们一直认为物体视觉与视觉系统的一个特定部分有关，这个部分被称为“腹侧系统”。腹侧系统受损的病人通常在识别物体方面有缺陷。然而，最近，在视觉系统的不同部分发现了第二个用于表示物体信息的系统，称为“背侧系统”。这一发现表明，物体信息可能在至少两个平行的神经系统中表现出来，这些神经系统可能服务于不同的行为目标。在这个项目中，通过使用脑成像（功能性磁共振成像；fMRI）对三种类型的参与者：(1)健康人，(2)猴子和(3)腹侧系统病变患者解决了关于背侧物体信息系统的几个问题。对于该项目的第一部分，研究人员正在研究背部物体信息的本质，以及它与腹侧流中表示的信息有何不同。对于该项目的第二部分，他们正在研究人类和猴子在背部系统中对物体信息的表征是否不同，也许，这反映了一种进化过程，以支持复杂的人类特定行为（例如，工具使用）。对于项目的第三部分，通过对患者的检查，他们正在解决一个重要的问题，即背侧系统是否依赖于腹侧系统，或者它是否作为一个独立的平行物体通路发挥作用。这些目标是通过在不同物种和不同参与者群体中使用几乎相同的方法来实现的。研究人员假设，背流物体处理系统是人类独有的，并且已经进化到支持复杂的工具使用。虽然许多研究都是针对腹侧系统中的物体表征，但本项目侧重于背侧系统中的物体处理，这是物体视觉中一个尚未得到充分研究的方面。重要的是，这种方法在不同的物种和参与者群体中使用几乎相同的方法，可以对认知的进化产生罕见的见解。复杂的工具使用和语言功能的发展被认为是人类独有的。虽然人们对语言的神经基础了解很多，但对工具使用的神经基础却知之甚少。本项目的成果旨在填补这一空白。从这个项目中获得的知识有望对人类学等其他学科产生重要影响。使用相同的技术和实验设计对人类和猴子进行比较研究，预计对下一代神经科学家来说将变得越来越重要。卡斯特纳博士的实验室是世界上为数不多的经常使用这类研究方法的实验室之一。因此，该项目为博士后、研究生和本科生提供了独特的培养机会。研究结果被用于Kastner博士继续向公众和当地公立学校推广的项目中。这些项目提高了人们对大脑研究重要性的认识和兴奋，并展示了现代神经科学研究的跨学科性质，以激励年轻学生追求科学事业，并帮助增加公众对基础科学研究的支持。

Humans have an amazing ability to visually identify a virtually limitless number of objects and to categorize them into classes such as faces, cars, or houses. We are capable of this feat despite the enormous variability in an object's appearance due to environmental factors such as distance, viewing angle, lighting, etc. With funding from the National Science Foundation, Sabine Kastner, Ph.D., of Princeton University is studying one of the major areas in the field of cognitive neuroscience, the neural mechanisms underlying efficient visual recognition. Object vision has long been associated with a specific part of the visual system, known as the 'ventral system.' Patients who suffer from damage to the ventral system often have deficits in recognizing objects. However, recently, a second system for the representation of object information has been found in a different part of the visual system, known as the 'dorsal system.' This finding suggests that object information might be represented in at least two parallel neural systems that likely serve different behavioral goals. In this project, several issues with regard to the dorsal object information system are being addressed by using brain imaging (functional magnetic resonance imaging; fMRI) on 3 types of participants: (1) healthy humans, (2) monkeys, and (3) patients with lesions of the ventral system. For the first part of the project, the researchers are studying the nature of the dorsal object information, and how it differs from the information represented in the ventral stream. For the second part of the project, they are studying whether the representation of object information in the dorsal system differs between humans and monkeys, perhaps, reflecting an evolutionary process to support complex human-specific behaviors (e.g., tool use). For the third part of the project, through the examination of patients, they are addressing the important question of whether the dorsal system depends on the ventral system, or whether it functions as an independent parallel object pathway. These objectives are being pursued by using virtually identical methods across different species and across different participant populations. The researchers hypothesize that the dorsal stream object processing system is unique to humans and has evolved to support sophisticated tool use.While much research has been directed at object representations in the ventral system, this project focuses on object processing within the dorsal system, a vastly understudied aspect of object vision. Importantly, the approach using virtually identical methods across different species and participant populations can lead to rare insights into the evolution of cognition. The developments of sophisticated tool use and language functions are considered unique to humans. While much is known about the neural basis of language, the neural basis of tool use is not well understood. The results of this project are designed to fill this gap. The knowledge gained from this project is expected to be important for other disciplines, such as anthropology. Comparative studies in humans and monkeys using identical techniques and experimental designs are predicted to become increasingly important for the next generation of neuroscientists. Dr. Kastner's laboratory is one of very few in the world where the methods for such studies are used regularly. Therefore, the project provides a unique training opportunity for postdoctoral fellows, graduate and undergraduate students. The results are being used in Dr. Kastner's continued outreach program to public audiences and in local public schools. Such programs raise awareness and excitement about the importance of brain research, and demonstrate the interdisciplinary nature of modern neuroscience research to motivate young students to pursue scientific careers and help increase public support of basic science research.