In humans and other primates, visual information is processed in a parallel fashion, along different visual pathways. In the classical view, visual motion information is processed in the dorsal visual pathway, not the ventral visual pathway. A recent study in monkeys showed that, in contrast to the classical view, motion information is processed in both the dorsal and ventral visual pathways, and possibly serves different purposes.

　　This work was carried out by Peichao Li, Shude Zhu and others in Dr. Haidong Lu’s lab at the Institute of Neuroscience, Chinese Academy of Sciences. Using imaging techniques, they studied the functional organizations of motion neurons in area V4 of macaque monkeys’ brain. Area V4 is located in the ventral pathway and is traditionally thought to be in charge of color and form processing. Little is known about its functional role in processing motion information.

　　Using intrinsic signal optical imaging, the authors mapped the direction of motion responses over large fields of view in V1, V2, and V4 in anesthetized monkeys. They found that V4 contains direction-preferring domains (~0.3mm diameter) that are preferentially activated by visual stimuli moving in one direction. These direction-preferring domains normally occupy several restricted regions of V4 and tend to overlap with orientation- and color-preferring domains. Based on the imaging maps, the authors further recorded single-neurons inside these domains, their results showed a clustering, as well as a columnar organization of direction-selective neurons in these domains.

　　This is the first demonstration of a motion organization in the ventral visual pathway. These findings suggest that, in contrast to the view of feature-based pathway separation, dorsal and ventral visual pathways may be best viewed as a purpose-based-separation, in which both pathways are capable of processing the same visual information (for example, motion information) for different purposes (for example, object motion or object identification).

　　The research article entitled "A Motion Direction Preference Map in Monkey V4" was published in Neuron on April 24, 2013 as a cover story. This work was supported by the grants from Ministry of Science and Technology of China, Chinese Academy of Sciences and State Key Laboratory of Neuroscience.

　　Top left: Neuron cover image for this research paper.

　　Top right: Imaging location and functional maps obtained from area V4.

　　Bottom: Dorsal vs. ventral visual pathways. The present study found that the ventral pathway processes not only color and shape, but also motion information (brain image modified from Lewis & van Essen 2000).