Trends in Cognitive Sciences
Review‘What’ Is Happening in the Dorsal Visual Pathway
Section snippets
Two Cortical Visual Pathways
One of the most influential conceptualizations within cognitive neuroscience asserts that the cortical visual system is segregated into two anatomically and functionally distinct pathways: the ventral visual pathway and the dorsal visual pathway (see Glossary). This division of labor, articulated in a seminal paper [1], and first inferred from lesion studies in monkeys and then in humans, proposes that the ventral pathway represents object shape and identity (‘what’), whereas the dorsal pathway
Independent Object-Selective Representations in the Dorsal Visual Pathway
Investigations of both human and non-human primates have revealed object-related neural activity in the dorsal pathway that is independent of action planning or execution 36, 37, 38, 39. Importantly, while much of the object-selective activation overlaps with the visuomotor system 7, 40 and probably reflects object representations that are in the service of action [41], at least some of the activation is dissociable from the visuomotor regions and is located more posteriorly or caudally within
‘What’ in the Dorsal Visual Pathway?
Taken together, the findings reviewed thus far indicate that dorsal object representations are dissociable from those generated in the ventral pathway, and play an independent and functional role in visual perception. In light of the above, we propose that visual perception should not be considered as the product of computations carried out solely by the ventral pathway, but instead as the joint outcome of the two pathways, both of which contribute to the representation of ‘what’ is perceived.
Concluding Remarks and Future Directions
The claim segregation and functional independence of the visual dorsal and ventral cortical pathways has provided one of the most influential frameworks for understanding the visual system over the past four decades, although the exact nature of the segregation has been re-evaluated, revised, and reconsidered over this time. Recent empirical evidence calls into question the binary distinctions between the two pathways, and suggests that the dorsal pathway is involved in – and is possibly even
Acknowledgments
This study was supported by a Yad-Hanadiv Postdoctoral Fellowship to E.F., a grant from the Israel Science Foundation to E.F. (65/15), a grant from the National Science Foundation to M.B. (BCS-1354350), a grant (SBE0542013) from the Temporal Dynamics of Learning Center (PI, G. Cottrell; Co-PI, M.B.) and by a grant from the Pennsylvania Department of Health Commonwealth Universal Research Enhancement Program (D.C.P.).
Glossary
- Affordance
- a set of potential actions that are offered to the organism by the environment/object. According to Gibson [126], the process of object perception automatically includes the extraction of affordance values.
- Dorsal visual pathway
- this pathway extends from the primary visual cortex (V1) in the occipital lobe to the parietal lobe. The dorsal pathway is subdivided by the intraparietal sulcus (IPS) into several main sectors including the superior parietal lobule, inferior parietal lobule,
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