10 files

The large-scale organization of shape processing in the ventral and dorsal pathways: Protocols

posted on 04.10.2017, 18:38 authored by Erez Freud, Jody Culham, David Plaut, Marlene Behrmann
The protocols for the 8 functional runs (numbers reflect TRs). The "protocol by run" file describes for each participant, the correspondence between runs and protocols.

Although shape perception is considered a function of the ventral visual pathway, evidence suggests that the dorsal pathway also derives shape-based representations. In two psychophysics and neuroimaging experiments, we characterized the response properties, topographical organization and perceptual relevance of these representations. In both pathways, shape sensitivity increased from early visual cortex to extrastriate cortex but then decreased in anterior regions. Moreover, the lateral aspect of the ventral pathway and posterior regions of the dorsal pathway were sensitive to the availability of fundamental shape properties, even for unrecognizable images. This apparent representational similarity between the posterior-dorsal and lateral-ventral regions was corroborated by a multivariate analysis. Finally, as with ventral pathway, the activation profile of posterior dorsal regions was correlated with recognition performance, suggesting a possible contribution to perception. These findings challenge a strict functional dichotomy between the pathways and suggest a more distributed model of shape processing.


National Science Foundation (NSF) - BCS-1354350; Canadian Institute of Health Research MOP 130345; Pennsylvania Department of Health's Commonwealth Universal Research Enhancement Program; Israel Science Foundation (ISF) grant No. 65/15