Brain BehaviorA1
The Two Stream Hypotheses
One of the primary principles of the visual system is the division between the dorsal and ventral streams. Both streams arise in the primary visual cortex but terminate at different locations in the brain. The ventral stream extends along the ventral surface into the inferior temporal cortex while the dorsal stream continues along the dorsal surface into the posterior parietal cortex. I will compare and contrast the views of Ungerleider and Mishkin vs. Milner and Goodale, both of which are influential today.
Ungerleider and Mishkin used the phrase “what vs. where” to distinguish between the division of roles of the ventral vs. dorsal visual streams. They proposed that the ventral stream is concerned with object identification and color (what) while the dorsal stream is responsible for object localization (where). Their reseach was concerned with separating the input of information into two different streams.
Goodale and Milner added to the research of Ungerleider and Mishkin; they proposed that the spatial and structural attributes of an object are processed by both streams but for different purposes. Instead of Ungerleider and Mishkin’s “what vs. where” proposal, Goodale and Milner suggested using “what” and “how” to describe the roles of the ventral and dorsal streams. They suggest that the ventral stream plays the major role in composing the representation of the visual world and objects within it (what).These representations play an important role in identifying objects and allowing us to attach meanings to them. Goodale and Milner also proposed that the dorsal stream is responsible for the visual control of actions directed at those objects (how) and not just to identify spatial localization of objects. As Dr. Marrotta stated: “Goodale and Milner’s research focuses on behavioral output rather than a separation of sensory input.” Goodale and Milner supported their findings by examining and observing the behavior of numerous patients
One of the primary principles of the visual system is the division between the dorsal and ventral streams. Both streams arise in the primary visual cortex but terminate at different locations in the brain. The ventral stream extends along the ventral surface into the inferior temporal cortex while the dorsal stream continues along the dorsal surface into the posterior parietal cortex. I will compare and contrast the views of Ungerleider and Mishkin vs. Milner and Goodale, both of which are influential today.
Ungerleider and Mishkin used the phrase “what vs. where” to distinguish between the division of roles of the ventral vs. dorsal visual streams. They proposed that the ventral stream is concerned with object identification and color (what) while the dorsal stream is responsible for object localization (where). Their reseach was concerned with separating the input of information into two different streams.
Goodale and Milner added to the research of Ungerleider and Mishkin; they proposed that the spatial and structural attributes of an object are processed by both streams but for different purposes. Instead of Ungerleider and Mishkin’s “what vs. where” proposal, Goodale and Milner suggested using “what” and “how” to describe the roles of the ventral and dorsal streams. They suggest that the ventral stream plays the major role in composing the representation of the visual world and objects within it (what).These representations play an important role in identifying objects and allowing us to attach meanings to them. Goodale and Milner also proposed that the dorsal stream is responsible for the visual control of actions directed at those objects (how) and not just to identify spatial localization of objects. As Dr. Marrotta stated: “Goodale and Milner’s research focuses on behavioral output rather than a separation of sensory input.” Goodale and Milner supported their findings by examining and observing the behavior of numerous patients