Frontiers in Computational Neuroscience Computational Neuroscience

Abstract

the brain where we would expect dorsal/ventral differences to be highly salient. Those two structures are anterior inferotemporal cortex (AIT) and lateral intraparietal cortex (LIP), studied under identical task conditions. This complements a previous report in which we demonstrated major differences at a population level of analysis in shape encoding within those two structures (Lehky and Sereno, 2007). Under one influential framework for understanding dorsal/ventral differences, ventral processing is viewed as oriented toward perception and memory, while dorsal processing is more oriented toward visuomotor control (Ungerleider and Mishkin, 1982; Goodale and Milner, 1992; Jeannerod and Jacob, 2005; Milner and Goodale, 2006). Within that framework, both dorsal and ventral visual structures contain spatial information, but the kind of spatial information differs. Dorsal spatial representations may be predominantly egocentric (Colby, 1998; Duhamel et al., 1998; Boussaoud and Bremmer, 1999; Snyder, 2000). Egocentric representations involve coordinate frames in which objects or locations are represented relative to the observer (e.g., retinotopic or eye-centered, head-centered, and IntroductIon The distinction between ventral and dorsal visual processing has traditionally been described in terms of a “what” vs. “where” dichotomy (Ungerleider and Mishkin, 1982; Ungerleider and Haxby, 1994). In recent years, however, that distinction has become blurred. Shape information has been found in the dorsal stream (Sereno and Maunsell, 1998; Murata et al., 2000; Sereno et al., 2002; Sereno and Amador, 2006; Janssen et al., 2008; Peng et al., 2008), while spatial information has been found in the ventral stream (Op de Beeck and Vogels, 2000; Lehky et al., 2008). It is becoming increasingly apparent that both visual streams are processing shape as well as spatial information. The differences between them appear not to be based on a strict dichotomy between shape and spatial processing, but rather on differences in the nature of shape and spatial information within each visual stream, with encoding of shape and space each geared to the different functionalities of dorsal and ventral processing. The objective of this study is to characterize differences in the representation of visual space between the two visual streams. Specifically, we compare spatial representations in regions of Population coding of visual space: comparison of spatial representations in dorsal and ventral pathways