Seeing without a Scene: Neurological Observations on the Origin and Function of the Dorsal Visual Stream

Author(s)Rafal, Robert D.
Date Accessioned2024-05-16T19:12:09Z
Date Available2024-05-16T19:12:09Z
Publication Date2024-05-11
DescriptionThis article was originally published in Journal of Intelligence. The version of record is available at: https://doi.org/10.3390/jintelligence12050050. © 2024 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
AbstractIn all vertebrates, visual signals from each visual field project to the opposite midbrain tectum (called the superior colliculus in mammals). The tectum/colliculus computes visual salience to select targets for context-contingent visually guided behavior: a frog will orient toward a small, moving stimulus (insect prey) but away from a large, looming stimulus (a predator). In mammals, visual signals competing for behavioral salience are also transmitted to the visual cortex, where they are integrated with collicular signals and then projected via the dorsal visual stream to the parietal and frontal cortices. To control visually guided behavior, visual signals must be encoded in body-centered (egocentric) coordinates, and so visual signals must be integrated with information encoding eye position in the orbit—where the individual is looking. Eye position information is derived from copies of eye movement signals transmitted from the colliculus to the frontal and parietal cortices. In the intraparietal cortex of the dorsal stream, eye movement signals from the colliculus are used to predict the sensory consequences of action. These eye position signals are integrated with retinotopic visual signals to generate scaffolding for a visual scene that contains goal-relevant objects that are seen to have spatial relationships with each other and with the observer. Patients with degeneration of the superior colliculus, although they can see, behave as though they are blind. Bilateral damage to the intraparietal cortex of the dorsal stream causes the visual scene to disappear, leaving awareness of only one object that is lost in space. This tutorial considers what we have learned from patients with damage to the colliculus, or to the intraparietal cortex, about how the phylogenetically older midbrain and the newer mammalian dorsal cortical visual stream jointly coordinate the experience of a spatially and temporally coherent visual scene.
SponsorThis research received no external funding.
CitationRafal, Robert D. 2024. "Seeing without a Scene: Neurological Observations on the Origin and Function of the Dorsal Visual Stream" Journal of Intelligence 12, no. 5: 50. https://doi.org/10.3390/jintelligence12050050
ISSN2079-3200
URLhttps://udspace.udel.edu/handle/19716/34414
Languageen_US
PublisherJournal of Intelligence
dc.rightsAttribution 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/
Keywordssuperior colliculus
Keywordsparietal lobe
KeywordsBálint’s syndrome
Keywordshemispatial neglect
Keywordsprogressive supranuclear palsy
TitleSeeing without a Scene: Neurological Observations on the Origin and Function of the Dorsal Visual Stream
TypeTutorial
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