The mechanisms underlying cortical motion selectivity

18.GOALSFORFELLOWSHITPRAINGING AND CAREER我的奖学金培训有三个主要目标。首先，我想从一个与以前不同的角度来研究神经处理。我的博士工作是在一个实验室进行的，该实验室在两种眼睛行为(平滑追逐和前庭-眼睛反射)的背景下研究视觉处理，而我目前的博士后工作是在一个实验室进行的，该实验室关注的是构成视觉处理的神经机制。对我来说，这将是一个重大的理论转变，从研究视觉系统中产生视觉行为的信号，到研究产生这种视觉信号的电路。我获得奖学金的第二个目标是学习一项新技术。我之前的经验是体内细胞外生理学和动物行为；现在我将学习体内细胞内记录技术，以研究突触连接和细胞功能。我的最终目标是阐明在初级视觉皮质V(V1)神经元中发生的感觉转换之一：方向选择性。19.NAMEANDDEGREE(S)David Ferster，博士20.西北大学教授职位/职级21.研究哺乳动物视觉处理的中心机制；哺乳动物新皮质的神经功能22.描述(不超过所提供的空间)大脑用来快速处理信息的一种策略是使用多个并行路径来同时分析世界的不同方面。视觉场景的分析被认为被分成三条平行的路径，专门处理颜色、形状和运动。在此期间，我们将研究视觉皮质中第三条通路--运动选择性的神经机制。V1中的运动处理需要有选择地对世界上移动物体的方向和速度做出反应的皮质神经元。方向选择性是一种在V1神经元中从头产生的神经元反应特性：它不存在于向皮质提供视觉输入的外侧膝状体(LGN)神经元中。与方向选择性等其他纯空间反应特性不同，方向选择性需要在时间域和空间域中进行处理：方向选择性神经元不仅必须识别对象所在的位置，还必须识别它在前一刻的位置。因此，方向选择性被认为是通过将具有不同感受野位置和不同时间延迟的LGN神经元的输入组合在一起而产生的。我们将研究来自LGN的信号是如何转换和组合的，以给予V1中的神经元方向选择性反应。通过学习和理解方向选择性，我们将学习信息加工的规则，这些规则可能普遍适用于时间信息的皮层加工。PHS 416-1(12/98版)表第2页bb cc个人非RSA申请目录========================================Section End===========================================

18. GOALSFORFELLOWSHITPRAININGANDCAREER I have three primary goals for my fellowship training. First, I want to study neural processing from a different perspective than I have previously. My doctoral work was in a lab that studies visual processing in the context of two ocular behaviors (smooth pursuit and the vestibulo- ocular reflex), while my current postdoctoral work is in a lab that is concerned with the neuronal mechanisms that underlie visual processing. For me, this will be a significant theoretical shift from studying the signals in the visual system that give rise to visual behavior, to studying the circuitry that gives rise to such visual signals. The second goal I have for my fellowship is to learn a new technique. My prior experience is in extracellular physiology in vivo and animal behavior; now I will learn the technique of intracellular recording in vivo to study synaptic connectivity and cellular function. My final goal is to clarify one of the sensory transformations that occurs in neurons of the prim_visual cortex V(V1): direction selectivity. _PONSOR 19. NAMEANDDEGREE(S) David Ferster, Ph.D. 20. POSITION/RANK Professor, Northwestern University 21.RESEARCIHNTERESTS/AREAS Central mechanisms of mammalian visual processing; Neuronal function of mammalian neocortex 22. DESCRIPTION (Do not exceed space provided) One strategy the brain uses to process information rapidly is the use of multiple parallel pathways to analyze different aspects of the world simultaneously. The analysis of a visual scene is thought to be segregated into three parallel pathways dedicated to the processing of color, shape, and motion. During this fellowship we will study the neuronal mechanisms that underlie the third pathway, motion selectivity, in visual cortex. Motion processing in V1 requires cortical neurons that respond selectively to the direction and speed of moving objects in the world. Direction selectivity is a neuronal response property that is created de novo in V1 neurons: it is not present in the neurons of the lateral geniculate nucleus (LGN) that provide visual input to the cortex. Unlike other purely spatial response properties such as orientation selectivity, direction selectivity requires processing in the time domain as well as the space domain: direction selective neurons must discern not only where an object is, but where it was in the previous moment. Direction selectivity is therefore thought to be created by combining inputs from LGN neurons with different receptive field positions and different temporal delays. We will investigate how the signals from the LGN are transformed and combined to give neurons in V1 their directionally selective responses. By studying and understanding direction selectivity, we will learn the rules of information processing that may apply generally to cortical processing of temporal information. PHS 416-1 (Rev. 12/98) Form Page 2 BB cc Individual NRSA Application Table of Contents ========================================Section End===========================================