双流假说（英语：two-streams hypothesis）是一个颇具影响力的视觉信息神经处理模型。这一假说认为人类大脑中拥有两种视觉系统，当视觉信息从枕叶传出后经由两条路径传递，其中参与物体识别的腹流（ventral stream）进入颞叶，而参与空间位置信息处理的背流（dorsal stream）则最终进入顶叶。因而腹流又被称为内容通路（what pathway），背流又被称为空间通路（where pathway）。

The two-streams hypothesis is a widely accepted and influential model of the neural processing of vision as well as hearing. The hypothesis, given its most popular characterisation in a paper by David Milner and Melvyn A. Goodale in 1992, argues that humans possess two distinct visual systems. However, recently there seems to be evidence of two distinct auditory systems as well. As visual information exits the occipital lobe, and as sound leaves the phonological network, it follows two main pathways, or "streams". The ventral stream (also known as the "what pathway") is involved with object and visual identification and recognition. The dorsal stream (or, "where pathway") is involved with processing the object's spatial location relative to the viewer and with speech repetition. Another model for the pe****tual/conceptual neuropsychological model of the visual cortex was studied by Raftopoulos. In Russian neuropsychology, yet another model was discussed by Alexander Luria for the anterior/posterior approach to understanding the visual cortex.