Northmore David P M
Dept. of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, USA.
Vision Res. 2017 Feb;131:44-56. doi: 10.1016/j.visres.2016.12.001. Epub 2017 Jan 3.
Only ray-finned fishes possess a torus longitudinalis (TL), a paired, elongated body attached to the medial margins of the optic tectum. Its granule cells project large numbers of fine fibers running laterally over adjacent tectum, synapsing excitatorily on the spiny dendrites of pyramidal cells. Sustained TL activity is evoked visuotopically by dark stimuli; TL bursting is a corollary discharge of saccadic eye movements. To suggest a function for this ancient structure, neural network models were constructed to show that: (1) pyramidal cells could form an attentional locus, selecting one out of several moving objects to track, but rapid image shifts caused by saccades disrupt tracking; (2) TL could supply both the pre-saccade position of a locus, and the shift predicted from a saccade so as to prime pyramidal dendrites at the target location, ensuring the locus stays with the attended object; (3) that the specific pattern of synaptic connections required for such predictive priming could be learned by an unsupervised rule; (4) temporal and spatial filtering of visual pattern input to TL allows learning from a complex scene. The principles thus evinced could apply to trans-saccadic attention and visual stability in other species.
只有硬骨鱼拥有纵走隆起（TL），这是一对附着于视顶盖内侧边缘的细长结构。其颗粒细胞投射出大量细纤维，这些纤维横向延伸至相邻的顶盖，并在锥体细胞的棘状树突上形成兴奋性突触。持续的TL活动由视觉刺激以视拓扑方式诱发；TL爆发是眼球扫视运动的一种伴随放电。为了揭示这个古老结构的功能，构建了神经网络模型来表明：（1）锥体细胞可以形成一个注意力位点，从多个移动物体中选择一个进行跟踪，但扫视引起的快速图像移动会干扰跟踪；（2）TL可以提供位点的扫视前位置以及根据扫视预测的移动，从而在目标位置使锥体细胞树突做好准备，确保位点与被关注物体保持一致；（3）这种预测性准备所需的特定突触连接模式可以通过无监督规则学习；（4）输入到TL的视觉模式的时间和空间过滤允许从复杂场景中学习。由此证明的这些原理可能适用于其他物种的跨扫视注意力和视觉稳定性。
