Ventral and Dorsal Visual Stream Contributions to the Perception of Object Shape and Object Location

Abstract

Growing evidence suggests that the functional specialization of the two cortical visual pathways may not be as distinct as originally proposed. Here, we explore possible contributions of the dorsal “where/how” visual stream to shape perception and, conversely, contributions of the ventral “what” visual stream to location perception in human adults. Participants performed a shape detection task and a location detection task while undergoing fMRI. For shape detection, comparable BOLD activation in the ventral and dorsal visual streams was observed, and the magnitude of this activation was correlated with behavioral performance. For location detection, cortical activation was significantly stronger in the dorsal than ventral visual pathway and did not correlate with the behavioral outcome. This asymmetry in cortical profile across tasks is particularly noteworthy given that the visual input was identical and that the tasks were matched for difficulty in performance. We confirmed the asymmetry in a subsequent psychophysical experiment in which participants detected changes in either object location or shape, while ignoring the other, task-irrelevant dimension. Detection of a location change was slowed by an irrelevant shape change matched for difficulty, but the reverse did not hold. We conclude that both ventral and dorsal visual streams contribute to shape perception, but that location processing appears to be essentially a function of the dorsal visual pathway.

Towards a unified perspective of object shape and motion processing in human dorsal cortex

“…Importantly, however, the extent to which ventral or dorsal areas are recruited during shape perception may be heavily task-dependent. For example, when observers are asked to report a location change across multiple presentations of an object, both ventral (LOC) and dorsal (PPC) regions are also sensitive to simultaneous changes in the object’s shape and identity, even though location was the only task-relevant property (Zachariou, Kltazky, & Behrmann, 2014). In contrast, when the task is to notice a shape difference across repeated presentations and location is irrelevant, only dorsal areas show location sensitivity.…”

Structural brain aberrations associated with the dissociative subtype of post‐traumatic stress disorder

“…The inferior temporal gyrus is part of the ventral visual stream and subserves shape perception and recognition memory for patterns, faces and objects (43,44). In a previous study, participants reporting greater depersonalization/derealization showed reduced theta activity in the temporal lobe (45).…”

A Preliminary Prospective Study of an Escalation in ‘Maximum Daily Drinks’, Fronto-Parietal Circuitry and Impulsivity-Related Domains in Young Adult Drinkers

“…Default mode network alterations have been observed in adult alcoholics during resting state, although increased connectivity patterns may compensate for these deficiencies during task performance (Müller-Oehring et al, 2014). The temporo-occipito-parietal network may facilitate the integration of ventro-lateral and dorsal visual streams involved in stimuli shape detection (eg, 'X' or 'K' in the current Go/NoGo task) (Zachariou et al, 2014). The lack of MaxDrinksrelated differences in these networks in young drinkers suggests these mechanisms may be intact during response inhibition.…”