invariant visual representation by single neurons in the human brain

This robustness to image transformations constitutes one of the major challenges for computer-based visual recognition, because most of the image pixels can change dramatically while the content remains the same. Given that an object can cast an infinite number of projections on the retina, our ability to recognize objects in a manner that is robust to object transformations is likely to have played a key role in the evolution of the visual system. A key to vision is that we can successfully recognize objects despite transformations in size, position, rotation, and illumination, among others (Figure 2). Visual selectivity refers to the ability to discriminate among similar objects. Visual object recognition depends on combining two key properties: visual selectivity and the robustness of recognition to object transformations. In a small fraction of a second (approximately 150 ms), we can recognize complex shapes and categorize objects and scenes ( 3, 6– 10). Visual object recognition is essential for most everyday tasks, including reading, navigation, and face identification. The appearance of visual problems after cortical damage is not surprising, given that a large part of the cerebral cortex serves visual processing functions ( 1– 5).Īmong the many functions of vision, object recognition is arguably one of the most crucial. There are abundant reports in the literature of cases that involve visual deficits that are caused by damage to cerebral cortex. 1.Įven though many visual deficits that are presented clinically relate to the eyes, the retina mediates only the initial steps in processing visual information. Many important visual areas and connections are not represented in this diagram for more details, see ref. As emphasized in the text, this diagram is a substantial simplification of the actual connectivity in the primate visual system. Solid lines indicate forward projections dashed lines indicate back-projections and the curved lines represent recurrent connections within a given area. VP, ventral stream DP, dorsal stream RGC, retinal ganglion cells CIT, central ITC AIT, anterior ITC MST, medial superior temporal cortex POR, post-rolandic area PR, pre-rolandic area. On the right, we provide a schematic description of some of the main pathways involved in processing visual information in cortex. On the left, we show a schematic diagram of the human brain indicating the approximate location of several brain areas discussed in the text.

Schematic illustration of the basic architecture in the primate visual system.

Invariant visual representation by single neurons in the human brain