Abstract
There are two main anatomically and physiologically defined visual pathways connecting the primary visual cortex with higher visual areas: the ventral and the dorsal pathway. The influential two-visual-systems hypothesis postulates that visual attributes are analyzed differently for different functions: in the dorsal pathway visual information is analyzed to guide actions, whereas in the ventral pathway visual information is analyzed for perceptual judgments. We here show that a person who cannot identify objects due to an extensive bilateral ventral brain lesion is able to judge the velocity at which an object moves. Moreover, both his velocity judgements and his interceptive actions are as susceptible to a motion illusion as those of people without brain lesions. These findings speak in favor of the idea that dorsal structures process information about attributes such as velocity, irrespective of whether such information is used for perceptual judgments or to guide actions.
Highlights
There are two main anatomically and physiologically defined visual pathways connecting the primary visual cortex with higher visual areas: the ventral and the dorsal pathway
Two main visual pathways have been identified in the human brain: one going from the primary visual cortex to the inferior temporal cortex via V4 and one from the primary visual cortex to the posterior parietal cortex via the middle temporal visual area (MT, dorsal pathway)[1]
According to the two-visual-systems hypothesis, perceptual illusions originate in the ventral pathway, where all information that could help make perceptual judgments is taken into account
Summary
There are two main anatomically and physiologically defined visual pathways connecting the primary visual cortex with higher visual areas: the ventral and the dorsal pathway. According to the two-visual-systems hypothesis, all visual attributes are processed twice: in the ventral pathway for recognizing objects (perception) and in the dorsal pathway for guiding one’s hand towards them (action)[4]. This claim is based on the notion that in order to perform an action such as grasping a cup, people primarily need information about the cup’s precise position with respect to themselves. One reason why the same findings can be interpreted in different ways is that illusions often only influence a specific attribute, and there is no consensus about the attributes that are used to guide some actions[15]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
