What are some of the differences in processing in the dorsal and ventral visual pathways? Imagine you have a friend who has an injured dorsal or ventral visual pathway, describe what that looks like, what deficits would be in their daily functioning, what remains intact.
Visual processing, and subsequent perception, is believed to have two separate pathways; the dorsal and ventral paths (Sheth & Young, 2016). The ventral perceives the “what”, while the dorsal perceives the “where”, as well as visuo-motor control(Sheth & Young, 2016). Visual spatial information originates in the dorsal region of the occipital lobe and goes to the parietal cortex where information is integrated with other senses to gain perception about spatial awareness and the environment (Gazzaniga et al., 2019). Information about object recognition originates in the ventral region of the occipital lobe and goes to the temporal cortex, where it may trigger aspects of memory, emotion and help with processing language (Gazzaniga et al., 2019).
Information processed by the dorsal portion of the occipital lobe is necessary for things like hand-eye coordination (Sheth & Young, 2016). Individuals with damage to the dorsal pathway may be able to identify an object, including its size and shape, but have difficulty coordinating their hand movement to locate and grasp the object (Sheth & Young, 2016). Reaching to pick up a pencil to write, or drinking a cup of coffee would be inhibited by an inability to accurately perceive the location of an object (Sheth & Young, 2016). On the other hand, being able to recognize objects and their significance may allow a person with damage to still make sense of the world around them, read, and continue making connections between objects and memory (Sheth & Young, 2016).
Information processing through the ventral visual pathway is essential in object recognition and facilitates higher level cognition about what an object represents and causal relationships involving objects (Sheth & Young, 2016). A person with damage to the ventral pathway would likely be aware of the presence of an object but may not be able to identify what it is, either in shape and size, or the significance of the object (Sheth & Young, 2016). This would effectively lead to an inability to do things like read, make correlations between object and person relevance (significance of an object) (Sheth & Young, 2016). This could create a lot of confusion in the brain if the stimulus input is not able to compute and provide accurate information for perception.
Sheth B. R. & Young R. (2016). Two visual pathways in primates based on sampling of space: Exploitation and exploration of visual information. Frontiers in Integrative Neuroscience, 10, 37. https://www.frontiersin.org/article/10.3389/fnint.2016.00037