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'''Two-streams hypothesis''' is a model proposed by Melvyn A. Goodale and A. David Milner to explain the processing of visual information in the brain. According to this hypothesis, the brain uses two separate pathways, or "streams", to process visual information: the ventral stream and the dorsal stream.
{{Short description|Hypothesis about the dual pathways in the brain for processing visual information}}


The '''[[ventral stream]]''' (also known as the "what pathway") is involved in object recognition and form representation. It extends from the [[primary visual cortex]] in the occipital lobe forward into the temporal lobe. It is associated with the perception of color, shape, and size of objects.
The '''two-streams hypothesis''' is a model of the neural processing of vision as proposed by [[David Milner]] and [[Melvyn A. Goodale]]. This hypothesis suggests that there are two distinct pathways in the brain for processing visual information: the dorsal stream and the ventral stream.


The '''[[dorsal stream]]''' (also known as the "where pathway") is involved in spatial awareness and guidance of actions. It extends from the primary visual cortex into the parietal lobe. It is associated with the perception of motion, spatial orientation, and control of the visual guidance of movements.
==Overview==
The two-streams hypothesis posits that visual processing in the brain is divided into two pathways:


The two-streams hypothesis has been influential in neuroscience and psychology, and has been supported by a number of studies. However, it has also been the subject of debate and revision, with some researchers proposing modifications or alternatives to the model.
* The '''dorsal stream''', often referred to as the "where" or "how" pathway, is involved in the spatial awareness and guidance of actions. It extends from the [[primary visual cortex]] to the [[parietal lobe]].
* The '''ventral stream''', known as the "what" pathway, is responsible for object recognition and form representation. It runs from the primary visual cortex to the [[temporal lobe]].


== Ventral Stream ==
==Dorsal Stream==
[[File:T16-DorsalRepetition.png|thumb|right|Diagram of the dorsal stream]]
The dorsal stream is crucial for the perception of motion and spatial relationships. It allows individuals to interact with their environment by processing information about the location and movement of objects. This stream is associated with the parietal cortex and is involved in the coordination of eye and arm movements, such as reaching and grasping.


The ventral stream is involved in the recognition of objects. It is responsible for determining "what" an object is. This stream begins in the primary visual cortex, and extends forward into the inferior temporal cortex. It is associated with the perception of color, shape, and size of objects.
==Ventral Stream==
[[File:T16-VentralComprehension.png|thumb|right|Diagram of the ventral stream]]
The ventral stream is essential for identifying objects and understanding their significance. It processes detailed visual information to recognize shapes, colors, and faces. This stream is linked to the temporal cortex and plays a key role in visual memory and the perception of complex stimuli.


== Dorsal Stream ==
==Historical Background==
The concept of dual visual pathways was first introduced in the 1980s by Ungerleider and Mishkin, who proposed the idea of separate pathways for processing "what" and "where" information. Milner and Goodale later expanded on this model, emphasizing the functional differences between the two streams.


The dorsal stream is involved in the spatial awareness and guidance of actions. It is responsible for determining "where" an object is. This stream begins in the primary visual cortex, and extends into the posterior parietal cortex. It is associated with the perception of motion, spatial orientation, and control of the visual guidance of movements.
==Applications and Implications==
Understanding the two-streams hypothesis has significant implications for [[neuroscience]], [[psychology]], and [[clinical practice]]. It provides insights into how brain injuries can affect visual processing and has applications in the development of [[neuroprosthetics]] and [[rehabilitation]] strategies for patients with visual impairments.


== Criticisms and Alternatives ==
==Criticism and Alternatives==
 
While the two-streams hypothesis is widely accepted, it has faced criticism and alternative models have been proposed. Some researchers argue for more integrated models of visual processing that do not strictly separate the functions of the dorsal and ventral streams.
While the two-streams hypothesis has been influential, it has also been the subject of criticism and revision. Some researchers have proposed modifications or alternatives to the model, suggesting that the division between "what" and "where" pathways is not as clear-cut as the original hypothesis suggests.
 
== See Also ==


==Related pages==
* [[Visual perception]]
* [[Visual perception]]
* [[Visual system]]
* [[Visual cortex]]
* [[Neuroscience]]
* [[Neuroscience]]
* [[Psychology]]
* [[Cognitive psychology]]
 
== References ==


<references />
==References==
* Milner, A. D., & Goodale, M. A. (1995). ''The Visual Brain in Action''. Oxford University Press.
* Ungerleider, L. G., & Mishkin, M. (1982). "Two cortical visual systems". In D. J. Ingle, M. A. Goodale, & R. J. W. Mansfield (Eds.), ''Analysis of Visual Behavior''. MIT Press.


[[Category:Neuroscience]]
[[Category:Neuroscience]]
[[Category:Psychology]]
[[Category:Visual perception]]
[[Category:Visual system]]
<gallery>
{{stub}}
File:T16-VentralComprehension.png|Ventral stream involved in comprehension
File:T16-DorsalRepetition.png|Dorsal stream involved in repetition
</gallery>

Latest revision as of 00:47, 18 February 2025

Hypothesis about the dual pathways in the brain for processing visual information


The two-streams hypothesis is a model of the neural processing of vision as proposed by David Milner and Melvyn A. Goodale. This hypothesis suggests that there are two distinct pathways in the brain for processing visual information: the dorsal stream and the ventral stream.

Overview[edit]

The two-streams hypothesis posits that visual processing in the brain is divided into two pathways:

  • The dorsal stream, often referred to as the "where" or "how" pathway, is involved in the spatial awareness and guidance of actions. It extends from the primary visual cortex to the parietal lobe.
  • The ventral stream, known as the "what" pathway, is responsible for object recognition and form representation. It runs from the primary visual cortex to the temporal lobe.

Dorsal Stream[edit]

File:T16-DorsalRepetition.png
Diagram of the dorsal stream

The dorsal stream is crucial for the perception of motion and spatial relationships. It allows individuals to interact with their environment by processing information about the location and movement of objects. This stream is associated with the parietal cortex and is involved in the coordination of eye and arm movements, such as reaching and grasping.

Ventral Stream[edit]

File:T16-VentralComprehension.png
Diagram of the ventral stream

The ventral stream is essential for identifying objects and understanding their significance. It processes detailed visual information to recognize shapes, colors, and faces. This stream is linked to the temporal cortex and plays a key role in visual memory and the perception of complex stimuli.

Historical Background[edit]

The concept of dual visual pathways was first introduced in the 1980s by Ungerleider and Mishkin, who proposed the idea of separate pathways for processing "what" and "where" information. Milner and Goodale later expanded on this model, emphasizing the functional differences between the two streams.

Applications and Implications[edit]

Understanding the two-streams hypothesis has significant implications for neuroscience, psychology, and clinical practice. It provides insights into how brain injuries can affect visual processing and has applications in the development of neuroprosthetics and rehabilitation strategies for patients with visual impairments.

Criticism and Alternatives[edit]

While the two-streams hypothesis is widely accepted, it has faced criticism and alternative models have been proposed. Some researchers argue for more integrated models of visual processing that do not strictly separate the functions of the dorsal and ventral streams.

Related pages[edit]

References[edit]

  • Milner, A. D., & Goodale, M. A. (1995). The Visual Brain in Action. Oxford University Press.
  • Ungerleider, L. G., & Mishkin, M. (1982). "Two cortical visual systems". In D. J. Ingle, M. A. Goodale, & R. J. W. Mansfield (Eds.), Analysis of Visual Behavior. MIT Press.