<p>My short answer would be that there is no clear relationship between these two models about how visual information processing works in the brain. However, the terminology and evidence overlaps considerably which makes this confusing.</p>

<p>One way to think about this is that the two models are explaining different stages of processing. The two visual streams is somewhat more general and it is very much founded on brain anatomy (lesion studies in animals and neuropsychology). It is to do with what happens to the visual information that comes into the brain, and the theory is that while some of it is processed to consciously recognise stuff (ventral), a separate pathway is involved with supplying visual information for action. </p>

<p>None of this is explicitly about "Attention". Corbetta and others are trying to relate brain structures to experiments in typical observers where processing changes even though stimuli are perceptually available. Although their two networks are sometimes called "dorsal and ventral", because of the involvement of superior/inferior brain regions, this does <em>not</em> imply that they map on to Milner and Goodale's visual streams. There are several other differences in anatomy.</p>

<p>It seems likely that <em>both</em> top-down and bottom-up attention can modulate perceptual processing in <em>both</em> visual streams (and they interact too!). It might help to think of some examples...</p>

<ul>
<li><p>If you are more likely to act on something when it is more salient
(e.g., avoiding a colourful obstacle without thinking about it) then
this suggests the "bottom-up" system has detected the obstacle and
prioritised it's processing for action (dorsal stream).</p></li>
<li><p>If you are voluntarily told to pay attention to something, and you
are quicker to act on this, it suggests that "top down" attention has
enhanced the dorsal stream.</p></li>
<li><p>If you are voluntarily told to pay attention to something and you are
quicker to recognise it, then this would be an effect on conscious<br>
recognition, thought to be part of the ventral stream.</p></li>
<li><p>If your attention is captured "bottom-up" by something, this is also 
going to make you better at consciously recognising it with your<br>
ventral stream.</p></li>
</ul>

<p><a href="http://www.pnas.org/content/103/26/10046.short" rel="nofollow">Here</a>, and <a href="http://nro.sagepub.com/content/20/2/150.short" rel="nofollow">here</a> are a couple of recent neuroscience papers on the attentional systems involved, and <a href="http://www.tandfonline.com/doi/abs/10.1080/713756776" rel="nofollow">here</a> is a classic paper showing attention is coupled in both perception and action streams.</p>

CC BY-SA 3.0
2016-06-02T15:30:02.087Z
2016-06-02T15:30:02.087Z
splint
<p>There are two visual attention networks proposed by Maurizio Corbetta and Gordon L. Shulman (2002). These are top-down and bottom-up attention networks.</p>

<blockquote>
  <p>One system, which includes parts of the intraparietal cortex and superior frontal cortex, is involved in preparing and applying goal-directed (top-down) selection for stimuli and responses. This system is also modulated by the detection of stimuli. The other system, which includes the temporoparietal cortex and inferior frontal cortex, and is largely lateralized to the right hemisphere, is not involved in top-down selection. Instead, this system is specialized for the detection of behaviourally relevant stimuli, particularly when they are salient or unexpected.</p>
</blockquote>

<p>There are also two ventral streams proposed by Melvyn A. Goodale and A. David Milner (1992). These are ventral stream and dorsal stream.</p>

<blockquote>
  <p>We propose that the ventral stream of projections from the striate cortex to the inferotemporal cortex plays the major role in the perceptual identification of objects, while the dorsal stream projecting from the striate cortex to the posterior parietal region mediates the required sensorimotor transformations for visually guided actions directed at such objects.</p>
</blockquote>

<p>My question: <strong>What is the relationship between these two proposed networks?</strong> As in do they affect each other, or is one a preliminary network that occurs before the other? There have been studies on this but I am having difficulty making sense of them.</p>

<p>Example: Visual streams and shifting attention (Brown 2009) <a href="http://www.sciencedirect.com/science/article/pii/S0079612309176045" rel="nofollow">http://www.sciencedirect.com/science/article/pii/S0079612309176045</a></p>

<blockquote>
  <p>To gain insight into the relationship between M/dorsal and P/ventral activity and deploying visual attention, we used a covert cuing paradigm to manipulate attention while bottom-up and top-down perceptual stimulus variables created M/dorsal and P/ventral-biased conditions. One study examined the object advantage, where responses are faster for within-relative to equidistant between-object shifts of attention. Visual stream contributions to object- and spaced-based attention were revealed using psychophysically equiluminant conditions expected to reduce M/dorsal activity. Other studies investigating visual stream contributions to location-based inhibition of return (IOR) used IOR magnitude as an indicator of the ease or difficulty of deploying spatial attention. Greater IOR was found under P/ventral-biased conditions. Less IOR was found under M/dorsal-biased conditions. </p>
</blockquote>

CC BY-SA 3.0
2016-05-30T20:23:42.843Z
What makes you assume the two systems are interconnected? Could you specify your question? The dorsal and ventral streams in the visual pathway are considered to be quite separate and dedicated to different aspects of vision. Therefore, they are considered separate streams. Hence, this makes your question difficult to answer, as there are tons of articles and books available on these two pathways alone - let alone on the other ones you include in your post. What exactly do you wish to know? As of now, this question is too broad to answer.
AliceD
CC BY-SA 3.0
2016-05-31T00:59:06.730Z
I assume them to have a relationship because both have connections to visual cortex. For top-down attention, it is assumed that visual stimulus goes through attention network where the network is already geared towards the part of visual field where stimulus is expected to appear.
Kenny Kim
CC BY-SA 3.0
2016-05-31T01:02:17.373Z
Visual streams have to do with recognizing and obtaining properties of the object of interest. To me, identification and attention of stimulus seems to be related, so I am confused on your statement that this is broad. Maybe I should have mentioned that I only care about visual attention network, although Corbetta's network is well known to be visual.
Kenny Kim
CC BY-SA 3.0
2016-05-31T01:05:16.087Z
I added a sub question to the main question in hopes that it better clarify my question.
Kenny Kim
CC BY-SA 3.0
2016-05-31T07:02:31.723Z
@Christiaan, if I may give my interpretation of the question: The ventral and dorsal stream are indeed two separate streams with separate functions, namely "what do I see" and "where do I see it" (very roughly speaking). What Kenny Kim, I think is wondering, is how the information is combined in the end, because this does occur (we can pinpoint exactly what where is). Although the question may seem broad, I would not know how to make it more specific.
Robin Kramer-ten Have
CC BY-SA 3.0
2016-05-31T07:18:31.867Z
@RobinKramer & OP, thanks for sharing your thoughts. I retracted my close-vote, but I doubt the question is answerable in its current format.
AliceD
CC BY-SA 3.0
2016-05-31T08:31:07.673Z
@Christiaan and RobinKramer I would love to make this question easier for people to answer, but I simply do not know how to make this more specific. It may be that I do not know enough about the stream networks to create a detailed question. I welcome any edit requests and since I am still looking into this area of study I may be able to edit the question in the future.
Kenny Kim
<neuroscience><vision><neural-network><attention>
What is the relationship between visual attention network and visual stream (Two-streams hypothesis)?
Kenny Kim
# What is the relationship between visual attention network and visual stream (Two-streams hypothesis)?

(Asked by: username_0 on 2016-05-28)

There are two visual attention networks proposed by Maurizio Corbetta and Gordon L. Shulman (2002). These are top-down and bottom-up attention networks.

> One system, which includes parts of the intraparietal cortex and superior frontal cortex, is involved in preparing and applying goal-directed (top-down) selection for stimuli and responses. This system is also modulated by the detection of stimuli. The other system, which includes the temporoparietal cortex and inferior frontal cortex, and is largely lateralized to the right hemisphere, is not involved in top-down selection. Instead, this system is specialized for the detection of behaviourally relevant stimuli, particularly when they are salient or unexpected.

There are also two ventral streams proposed by Melvyn A. Goodale and A. David Milner (1992). These are ventral stream and dorsal stream.

> We propose that the ventral stream of projections from the striate cortex to the inferotemporal cortex plays the major role in the perceptual identification of objects, while the dorsal stream projecting from the striate cortex to the posterior parietal region mediates the required sensorimotor transformations for visually guided actions directed at such objects.

My question: **What is the relationship between these two proposed networks?** As in do they affect each other, or is one a preliminary network that occurs before the other? There have been studies on this but I am having difficulty making sense of them.

Example: Visual streams and shifting attention (Brown 2009) <http://www.sciencedirect.com/science/article/pii/S0079612309176045>

> To gain insight into the relationship between M/dorsal and P/ventral activity and deploying visual attention, we used a covert cuing paradigm to manipulate attention while bottom-up and top-down perceptual stimulus variables created M/dorsal and P/ventral-biased conditions. One study examined the object advantage, where responses are faster for within-relative to equidistant between-object shifts of attention. Visual stream contributions to object- and spaced-based attention were revealed using psychophysically equiluminant conditions expected to reduce M/dorsal activity. Other studies investigating visual stream contributions to location-based inhibition of return (IOR) used IOR magnitude as an indicator of the ease or difficulty of deploying spatial attention. Greater IOR was found under P/ventral-biased conditions. Less IOR was found under M/dorsal-biased conditions.

**Tags:** neuroscience, vision, neural-network, attention

> **Comments:**
> **username_1**: What makes you assume the two systems are interconnected? Could you specify your question? The dorsal and ventral streams in the visual pathway are considered to be quite separate and dedicated to different aspects of vision. Therefore, they are considered separate streams. Hence, this makes your question difficult to answer, as there are tons of articles and books available on these two pathways alone - let alone on the other ones you include in your post. What exactly do you wish to know? As of now, this question is too broad to answer.  
> **username_0**: I assume them to have a relationship because both have connections to visual cortex. For top-down attention, it is assumed that visual stimulus goes through attention network where the network is already geared towards the part of visual field where stimulus is expected to appear.  
> **username_0**: Visual streams have to do with recognizing and obtaining properties of the object of interest. To me, identification and attention of stimulus seems to be related, so I am confused on your statement that this is broad. Maybe I should have mentioned that I only care about visual attention network, although Corbetta's network is well known to be visual.  
> **username_0**: I added a sub question to the main question in hopes that it better clarify my question.  
> **username_2**: @Christiaan, if I may give my interpretation of the question: The ventral and dorsal stream are indeed two separate streams with separate functions, namely "what do I see" and "where do I see it" (very roughly speaking). What username_0, I think is wondering, is how the information is combined in the end, because this does occur (we can pinpoint exactly what where is). Although the question may seem broad, I would not know how to make it more specific.  
> **username_1**: @RobinKramer & OP, thanks for sharing your thoughts. I retracted my close-vote, but I doubt the question is answerable in its current format.  
> **username_0**: @Christiaan and RobinKramer I would love to make this question easier for people to answer, but I simply do not know how to make this more specific. It may be that I do not know enough about the stream networks to create a detailed question. I welcome any edit requests and since I am still looking into this area of study I may be able to edit the question in the future.  

---

## 1 answers

### Answer by username_3 on 2016-06-02. Score: 3

My short answer would be that there is no clear relationship between these two models about how visual information processing works in the brain. However, the terminology and evidence overlaps considerably which makes this confusing.

One way to think about this is that the two models are explaining different stages of processing. The two visual streams is somewhat more general and it is very much founded on brain anatomy (lesion studies in animals and neuropsychology). It is to do with what happens to the visual information that comes into the brain, and the theory is that while some of it is processed to consciously recognise stuff (ventral), a separate pathway is involved with supplying visual information for action.

None of this is explicitly about "Attention". Corbetta and others are trying to relate brain structures to experiments in typical observers where processing changes even though stimuli are perceptually available. Although their two networks are sometimes called "dorsal and ventral", because of the involvement of superior/inferior brain regions, this does *not* imply that they map on to Milner and Goodale's visual streams. There are several other differences in anatomy.

It seems likely that *both* top-down and bottom-up attention can modulate perceptual processing in *both* visual streams (and they interact too!). It might help to think of some examples...

* If you are more likely to act on something when it is more salient
  (e.g., avoiding a colourful obstacle without thinking about it) then
  this suggests the "bottom-up" system has detected the obstacle and
  prioritised it's processing for action (dorsal stream).
* If you are voluntarily told to pay attention to something, and you
  are quicker to act on this, it suggests that "top down" attention has
  enhanced the dorsal stream.
* If you are voluntarily told to pay attention to something and you are
  quicker to recognise it, then this would be an effect on conscious  
  recognition, thought to be part of the ventral stream.
* If your attention is captured "bottom-up" by something, this is also
  going to make you better at consciously recognising it with your  
  ventral stream.

[Here](http://www.pnas.org/content/103/26/10046.short), and [here](http://nro.sagepub.com/content/20/2/150.short) are a couple of recent neuroscience papers on the attentional systems involved, and [here](http://www.tandfonline.com/doi/abs/10.1080/713756776) is a classic paper showing attention is coupled in both perception and action streams.


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