Local Circuits & Direction Selectivity in Visual Cortex

描述（来自申请人的摘要）：本项目提出使用 光学成像和单个单元记录技术来分析 雪貂初级视皮层方向特异性的底物。 提出的问题是，单个移动物体的各个方面都存在 关于其运动方向的冲突线索（例如，如图10所示， 在一个光圈的轮廓运动，或理发师极错觉）。然而，视觉 系统解决这些差异以预测运动的总体方向， 一个精确的眼球运动指南。拟议的研究详细审查了 V1中的神经元群体响应（通过光学成像）， 定向轮廓运动和相同轮廓的终止（其可以是 等同于点运动）。这些实验验证了一个假设， 感知的运动方向是对运动的响应的加权和。 不同方向的运动存在于刺激中。该总和可以是 受轮廓长度、对比度和速度的影响。单个单元记录将 可以用来测试单个神经元在不同点的属性， 光学地图，验证地图预测，测试 单点响应，以测试端点之间的空间交互 和轮廓驱动的活性，并且，与电压敏感染料成像一起， 检查来自终结者的信号的时间演变的差异， 轮廓

DESCRIPTION (From the Applicant's Abstract): This project proposes using the techniques of optical imaging and single unit recording to analyse the substrates for direction specificity in primary visual cortex of the ferret. The issue raised is that the various aspects of single moving objects present conflicting cues as to the direction of its motion (e.g. as illustrated by motion of contours in an aperture, or the barber pole illusion).Yet the visual system resolves these differences to predict an overall direction of motion and an accurate guide to eye movements. The proposed studies examine in detail the neuron population responses in V1 (by optical imaging) to movement of both oriented contour motion and the terminations of the same contour (which may be equated with dot motion). The experiments test the hypothesis that the perceived direction of motion is a weighted sum of the responses to the different directions of motion present in the stimulus. This sum can be affected by length of contour, contrast and speed. Single unit recording will be used to test the properties of single neurons at different points in the optical maps, to verify the map predictions, to test for variability of responses at single points, to test spatial interactions between terminal point and contour driven activity, and, together with voltage sensitive dye imaging, to examine differences in temporal evolution of signals from terminators and contours.