Chey J, Grossberg S, Mingolla E
Department of Cognitive and Neural Systems, Boston University, MA 02215, USA.
Vision Res. 1998 Sep;38(18):2769-86. doi: 10.1016/s0042-6989(97)00372-6.
A neural network model of visual motion perception and speed discrimination is presented. The model shows how a distributed population code of speed tuning, that realizes a size-speed correlation, can be derived from the simplest mechanisms whereby activations of multiple spatially short-range filters of different size are transformed into speed-turned cell responses. These mechanisms use transient cell responses to moving stimuli, output thresholds that covary with filter size, and competition. These mechanisms are proposed to occur in the V1-->MT cortical processing stream. The model reproduces empirically derived speed discrimination curves and simulates data showing how visual speed perception and discrimination can be affected by stimulus contrast, duration, dot density and spatial frequency. Model motion mechanisms are analogous to mechanisms that have been used to model 3-D form and figure-ground perception. The model forms the front end of a larger motion processing system that has been used to simulate how global motion capture occurs, and how spatial attention is drawn to moving forms. It provides a computational foundation for an emerging neural theory of 3-D form and motion perception.
本文提出了一种视觉运动感知和速度辨别神经网络模型。该模型展示了一种速度调谐的分布式群体编码如何实现大小-速度相关性，这种编码可从最简单的机制推导而来，即不同大小的多个空间短程滤波器的激活如何转化为速度调谐细胞反应。这些机制利用对移动刺激的瞬态细胞反应、与滤波器大小共变的输出阈值以及竞争。这些机制被认为发生在V1到MT的皮质处理流中。该模型再现了根据经验得出的速度辨别曲线，并模拟了数据，展示了视觉速度感知和辨别如何受到刺激对比度、持续时间、点密度和空间频率的影响。模型的运动机制类似于用于模拟三维形状和图形-背景感知的机制。该模型构成了一个更大的运动处理系统的前端，该系统已被用于模拟全局运动捕获如何发生，以及空间注意力如何被吸引到移动的形状上。它为新兴的三维形状和运动感知神经理论提供了计算基础。
