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Published June 1997 | public
Journal Article

Neural Mechanisms of Visual Motion Perception in Primates

Abstract

A large extent of the posterior cortex of the primate brain is devoted to vision, and it contains two general streams that process visual information. The one stream is situated more ventrally in the cortex and is important for object recognition, pattern recognition, color perception, and shape perception. These attributes of visual analysis we associate with visual awareness or "seeing", and thus this stream has been referred to as the "what" system because it recognizes objects (Ungerleider and Mishkin 1982). A second, more dorsal stream is associated with visual-motor transformations—that is, the routing of sensory information into motor areas for the purpose of action. This dorsal stream plays an important role in attention, decisions, and movement planning. It also plays an important role in spatial awareness, which is crucial for planning movements to locations in space and for transforming visually defined locations into movement coordinates to accomplish accurate motor behaviors. This pathway has been referred to as the "where" or "how" pathway because it tells us where and how to perform visually guided movements (41, 15). The motion processing stream is considered to be part of the dorsal "where" pathway, but it shares features of both these dorsal and ventral systems. The motion pathway analyzes visual motions to form percepts of complex motion patterns and of shape derived from movement cues; that is, it has similar perceptual functions to the ventral stream. However, it also plays important roles in visual-motor processing, including spatial awareness based on motion cues, and the analysis of motion information for the planning of motor behaviors such as tracking moving targets with the eyes.

Additional Information

© 1997 Cell Press. I wish to thank David Bradley, Jim Crowell, Krishna Shenoy, and Carol Andersen for comments on the manuscript; Sylvie Gertmenian for editorial assistance; and David Bradley and John Pezaris for assistance with the figures. The experiments from the author's laboratory discussed here were supported by grants from the National Eye Institute, the Sloan Center for Theoretical Neurobiology at Caltech, the Human Frontiers Scientific Program, and the Office of Naval Research.

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023