What is the ventral stream?
The ventral stream is an essential neurological pathway that carries information from the primary visual cortex to the inferior temporal lobe and other important structures. Information processing takes place pertaining to what the item is, its shape, and assisting in memory forming. The ventral stream is essential for interpreting optical stimuli.
How is the dorsal stream involved in visual processing?
The dorsal stream (or, "how pathway") terminates in the parietal lobe and is involved with processing the object's spatial location relevant to the viewer, in order to program behaviour. Several researchers had proposed similar ideas previously.
What is the function of the ventral and dorsal stream?
The visual information is processed by the ventral stream for visual perception (vision of perception). Meanwhile the dorsal stream processes visual information with the aim of movement implementation (vision of action) (Milner & Goodale, 2008; Sheth & Young, 2016). However.
What part of the brain is responsible for visual processing?
These streams run through the temporal and parietal lobes, which is why sometimes surgery to these parts of the brain can affect visual processing as well. The dorsal stream guides your actions and helps you recognize where objects are in space.
What is the ventral visual pathway?
What is the ventral pathway in a monkey?
What is the dorsal pathway?
Is the ventral visual pathway a recurrent network?
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What is the ventral stream also known as?
According to one widely-accepted hypothesis, the ventral stream (so named because of the path it takes along the ventral side of the brain) carries information related to object form and recognition. It is sometimes called the "what" pathway. See also: dorsal stream.
What is the ventral visual stream specialized for?
The ventral visual pathway is a functional stream involved in the visual recognition of objects. The anatomical substrates to the ventral visual pathway were initially identified in macaque monkeys by Mishkin and Ungerleider (1982).
What does the ventral Stream project to?
From the early visual areas, the ventral stream runs to the inferotemporal cortex, whereas the dorsal stream projects to the posterior parietal cortex.
What are the two main streams of processing in the visual system?
Two broad "streams" of projections from primary visual cortex have been identified: a ventral stream projecting to the inferotemporal cortex and a dorsal stream projecting to the posterior parietal cortex.
What is the difference between the dorsal and ventral visual streams?
From their model, the ventral stream processes visual information for the purpose of visual perception (“vision for perception”), while the dorsal stream processes visual information for the purpose of executing movements (“vision for action”).
Where does the ventral stream of visual object perception terminate?
The ventral stream (also known as the "what pathway") leads to the temporal lobe, which is involved with object and visual identification and recognition.
What and where is the ventral stream quizlet?
Also known as the ventral pathway, this stream of processing descends from the occipital cortex to the inferior temporal cortex and is involved in objects recognition. It is often referred to as the 'what' pathway owingtoits primary function.
What are the dorsal and ventral streams for language processing?
Built on an analogy between the visual and auditory systems, the following dual stream model for language processing was suggested recently: a dorsal stream is involved in mapping sound to articulation, and a ventral stream in mapping sound to meaning.
What does ventral mean in psychology?
directional term that refers to the front. When used in reference to the nervous system, ventral refers to the front when discussing the spinal cord. However, above the junction of the midbrain and diencephalon, ventral refers instead to the lower or inferior portion of the brain.
What is the dorsal visual stream?
Definition. The dorsal visual pathway is a functional stream originating in primary visual cortex and terminating in the superior parietal lobule that is responsible for the localization of objects in space and for action-oriented behaviors that depend on the perception of space.
What is your dorsal stream?
The dorsal stream, or where pathway, describes a hierarchy of areas that support visually-guided behaviors and localizing objects in space. It involves two main groups of areas, which receive separate, strong projections from V1. The lateral group in the dorsal stream consists of areas MT, MTc, MST, and FST.
Where is the ventral pathway in the brain?
The ventral pathway was described as coursing through the occipitotemporal cortex to the anterior part of the inferior temporal gyrus (area TE)[1, 2], with a likely extension into the ventrolateral prefrontal cortex (VLPFC/area FDv)[3].
What and where is the ventral stream quizlet?
Also known as the ventral pathway, this stream of processing descends from the occipital cortex to the inferior temporal cortex and is involved in objects recognition. It is often referred to as the 'what' pathway owingtoits primary function.
What happens if the ventral visual pathway is damaged?
Ventral damage can cause: Impairments in contrast sensitivity, form and color vision, and depth perception. Impairments in object and face perception and route-finding.
What are the two theories regarding the functions of the dorsal and ventral streams?
Two proposals theorize that the pathways are segregated in function: The ventral stream processes information about object identity, whereas the dorsal stream, according to one model, processes information about either object location, and according to another, is responsible in executing movements under visual control ...
What is the dorsal visual stream?
Definition. The dorsal visual pathway is a functional stream originating in primary visual cortex and terminating in the superior parietal lobule that is responsible for the localization of objects in space and for action-oriented behaviors that depend on the perception of space.
Ventral visual pathway - How Emotions Are Made
Your brain initiates your catch well before you consciously see the ball in the predicted location. You become aware of your intention to move your arm at about the same time as you become aware of seeing the ball in its current location, however, so it seems as if you see the ball and then move your arm to catch it.
Dorsal and Ventral Visual Pathways - LotsOfEssays.com
Visual information that comes to the cortex is processed in the occipital lobe of the brain and then can take either the dorsal (ôwhereö) or ventral (ôwhatö) visual pathway; in the dorsal pathway, visual information is projected into the parietal lobe, and in the ventral pathway, visual information is projected into the temporal lobe (Dawson & Medler, Dorsal; ôCortical Functions and Their ...
Relationship between ventral stream for object vision and dorsal stream ...
Recent imaging studies indicated the existence of two visual pathways in humans: a ventral stream for object and form vision and a dorsal stream for spatial and motion vision.
Damage to ventral and dorsal language pathways in acute aphasia
Abstract. Converging evidence from neuroimaging studies and computational modelling suggests an organization of language in a dual dorsal–ventral brain network: a dorsal stream connects temporoparietal with frontal premotor regions through the superior longitudinal and arcuate fasciculus and integrates sensorimotor processing, e.g. in repetition of speech.
What is the ventral visual pathway?
The ventral visual pathway: An expanded neural framework for the processing of object quality
What is the ventral pathway in a monkey?
The ventral pathway was described as a multisynaptic pathway projecting from striate cortex (cytoarchetectonic area OC) to area TE in the inferior temporal cortex, with a further projection from TE to ventral prefrontal region FDv. The dorsal pathway was described as a multisynaptic pathway projecting from striate cortex to area PG in the inferior parietal lobule, with a further projection from PG to dorsolateral prefrontal region FDΔ. On the basis of behavioral effects of lesions in the monkey, the ventral pathway was characterized as supporting object vision (‘what’), whereas the dorsal pathway was characterized as supporting spatial vision (‘where’). (Based on [1]; [2]; [3])
What is the dorsal pathway?
The dorsal pathway is an occipitoparietal network that lies between early visual cortex and specialized cortical structures involved in visually-guided action, somatosensation, spatial audition, navigation, and spatial working memory. The type of visual information required by these processes is very general. For example an observer’s hand and the target of a reaching movement can appear in any retinotopic positions and the occipitoparietal network must still create an accurate map of their relative positions to effectively guide the action. The need to represent these sorts of relationships naturally leads to the formation of coordinate systems and general reference frames. Thus, the dorsal pathway specializes in capturing arbitrary and dynamic spatiotemporal relationships between multiple items. Over time, however, the occipitoparietal cortex also contributes to the long-term representation of non-arbitrary spatiotemporal relationships as demonstrated by findings of apraxias[4] and tool-selective regions[283] localized within the posterior parietal cortex.. This framework has the advantage of parsimoniously incorporating a number of non-visual functions associated with the dorsal pathway (e.g. number[284], sequences[285], melody[286], prosody[287]).
Is the ventral visual pathway a recurrent network?
However, there is now a wealth of anatomical evidence suggesting that the ventral visual pathway is actually a complex recurrent network. V1 projects directly not just to V2, but also to V3[24], V4[25, 28], and MT[29–32]. Thus, visual information from V1 can reach TEO in two steps via V2, V4, or MT[16, 19, 25], violating a strict serial hierarchy at even the earliest stages of visual processing. There are also direct projections between V4d and TEpd[25] and between TEOd and TEad[16, 20, 33] that bypass the intermediate regions (Fig. 3A). In addition, there are unidirectional, nonreciprocal projections from putative late stages in the pathway to early stages (Fig. 3B). Finally, while the laminar structure of projections has been used to determine levels in the hierarchy, projections beyond V1 to V2 do not strictly follow those rules, with feedforward connections terminating instead across a broad range of lamina in the target areas. For example, connections from TEO to TEpd/TEad and from TEad/TEav to STSv/f terminate throughout all 6 cortical layers[20, 34].
What is visual processing?
Visual process is the capability to generate, perceive, analyse, synthesise, manipulate, transform and think with spatial patterns and stimuli (WISC–IV - 2008). Visual processing poses a huge computational challenge for the brain. The brain has evolved to well-ordered and effective neural systems to reach the demands. Over the past many years, in order to understand this neural system and complicated pathway, immense research has been done (Prasad & Galetta, 2011). Research suggests that, visual processing undertakes two fundamental objectives; to identify the visual stimuli and its location. Originally these objectives are known as “what” and “where” (Ungerleider & Mishkin, 1982). Whereas currently, terms such as “what” and “how” or “form and “motion” perception (Klaver et al., 2011) are used to objectify the functions of the two streams. The in-depth insight of the anatomy of the visual system along with skilled examination, recognizes the specific localization of the neuropathological processes. Moreover, these findings help in efficient diagnosis and treatment of visual processing, neuro-ophthalmic or neuropsychological disorders. There have been decades of research from a variety of sources like physiological studies in monkeys, neurophysiology, neuropsychology, neuroimaging and behavioural psychophysics to determine and describe functions of the two visual processing streams (for review see, Creem et al., 2001; Freud et al., 2016; Goodale et al., 2005; Milner & Goodale, 1995). The current essay will evaluate non-primate and neuropsychological patients’ studies to discuss the functions of both visual processing streams.
What are the two objectives of visual processing?
Research suggests that, visual processing undertakes two fundamental objectives; to identify the visual stimuli and its location . Originally these objectives are known as “what” and “where” (Ungerleider & Mishkin, 1982).
What is dorsal simultanagnosia?
Dorsal simultanagnosia is a condition wherein the bilateral parieto-occipital lesions have an impact on the dorsal stream. In this condition, patients are capable of object recognition but are not capable of viewing multiple objects at a time and the attentional impairment is affected by the object boundary. An exception being when the objects are small, spatially close and foveal (Luria, 1959; Humphreys & Riddoch, 1993). This suggest the role of dorsal stream in particular manner of object recognition especially for the blend of figure and background typically for the visual periphery. Furthermore, in this condition deficits in spatial vision as well as spatial attention has also been noted (Sheth & Young., 2016). The what/where model interpretation of the two visual pathways began facing issues. It is noted that the ventral pathway is not solely functional for vision only, it also undertakes the processing of visual features. However, ventral pathway is not only responsible for object recognition, the dorsal stream plays a role in it too. Dorsal pathway undertakes object recognition in a few conditions and also bares the responsibility of spatial vision and spatial attention. It can be noted from Ungerleider and Misjkin, 1982, in the study of parietal lesion in monkey where they suggest “...contralateral neglect of auditory and tactile as well as visual stimuli…” it is considered more included in the spatial attention than the visual attention (Lynch & McLaren, 1989; Sheth & Young, 2016).
What is the term for a bilateral parieto-occipital lesions that have an impact on?
Dorsal simultanagnosia is a condition wherein the bilateral parieto-occipital lesions have an impact on the dorsal stream. In this condition, patients are capable of object recognition but are not capable of viewing multiple objects at a time and the attentional impairment is affected by the object boundary.
Which stream is activated for the face and spatial location task?
Additionally, the ventral and dorsal stream was also activated for the face and spatial location task respectively. These results suggest the presence of two independent functional and anatomical visual processing streams in humans just as the monkeys.
Who is the author of Separate Visual Pathways for Perception and Action?
Goodale, M. A., & Milner, A. D. (1992). Separate visual pathways for perception and action. Trends in Neurosciences, 15 (1), 20–25.
Which part of the brain is responsible for object recognition?
Studies suggest that even though the ventral stream is mainly responsible for processing spatial details and high resolution visual features, it is now self-responsible for object recognition. The dorsal pathway also takes part in object recognition, not generally but in a few different situations for example, when the stimulus is unique or different in a manner. Object selective responses have been noted in the cortical areas of the dorsal pathway for objects with and without a semantic context (Konen & Kastner, 2008). The cortical region of the dorsal stream has been noted to be reactive to the feature of the stimuli which is to be monitored in the ventral stream. For example, in shape selectivity task, it was noticed that neurons of lateral intraparietal area in the dorsal stream were active of the monkey cortex (Sereno & Maunsell, 1998), transformation-invariant object selective response in the dorsal stream of human cortex (Konen & Kastner, 2008). Dorsal area also showed activation in the monkey cortex when there was a colour selection response task while the colour directed the eye movements (Toth & Assad, 2002) while in humans, colour discrimination caused dorsal area activation (Claeys et al., 2004).
What is visual processing?
Visual processing (or visual perception) describes the brain’s ability to understand and process what the eyes see. Visual processing is comprised of several different parts and includes:
Which part of the brain is responsible for visual processing?
These streams run through the temporal and parietal lobes, which is why sometimes surgery to these parts of the brain can affect visual processing as well. The dorsal stream guides your actions and helps you recognize where objects are in space. Also known as the parietal stream (because it flows to the parietal lobe ), the “where” stream, ...
Where is the stream in the parietal lobe?
Also known as the parietal stream (because it flows to the parietal lobe ), the “where” stream, or the “how” stream, this pathway stretches from the primary visual cortex (V1) in the occipital lobe forward into the parietal lobe. It is interconnected with the parallel ventral stream (the “what” stream) which runs downward from V1 into ...
Which stream of the brain is responsible for visual identification?
Then, that information exits the occipital lobes in white matter tract pathways called streams to other parts of the brain. The ventral stream (also known as the “what pathway”) is involved with object and visual identification and recognition. The dorsal stream (“or where pathway” ) is involved with processing the object’s spatial location.
What is the dorsal stream?
The dorsal stream (“or where pathway” ) is involved with processing the object’s spatial location. In other words, the brain is figuring out what to do with the visual information it has received; how to use it to recognize persons seen before; map routes; recognize symbols and letters; and many other interpretations.
Which lobe of the brain is responsible for object recognition?
The ventral stream is primarily involved with object recognition and form representation. Also described as the “what” stream, it has strong connections to the medial temporal lobe (which stores long-term memories), the limbic system (which controls emotions), and the dorsal stream (which deals with object locations and motion).
Where does visual information exit the brain?
Then, that information exits the occipital lobes in white matter tract pathways called streams to other parts of the brain.
History
Several researchers had proposed similar ideas previously. The authors themselves credit the inspiration of work on blindsight by Weiskrantz, and previous neuroscientific vision research. Schneider first proposed the existence of two visual systems for localisation and identification in 1969.
Two visual systems
Goodale and Milner amassed an array of anatomical, neuropsychological, electrophysiological, and behavioural evidence for their model, according to which the ventral ‘perceptual’ stream provides the rich and detailed representation of the visual world required for cognitive operations whereas the dorsal ‘action’ stream transforms incoming visual information into the required coordinates for skilled motor behaviour.
Criticisms
Goodale & Milner's innovation was to shift the perspective from an emphasis on input distinctions, such as object location versus properties, to an emphasis on the functional relevance of vision to behaviour, for perception or for action.
What is the ventral visual pathway?
The ventral visual pathway: An expanded neural framework for the processing of object quality
What is the ventral pathway in a monkey?
The ventral pathway was described as a multisynaptic pathway projecting from striate cortex (cytoarchetectonic area OC) to area TE in the inferior temporal cortex, with a further projection from TE to ventral prefrontal region FDv. The dorsal pathway was described as a multisynaptic pathway projecting from striate cortex to area PG in the inferior parietal lobule, with a further projection from PG to dorsolateral prefrontal region FDΔ. On the basis of behavioral effects of lesions in the monkey, the ventral pathway was characterized as supporting object vision (‘what’), whereas the dorsal pathway was characterized as supporting spatial vision (‘where’). (Based on [1]; [2]; [3])
What is the dorsal pathway?
The dorsal pathway is an occipitoparietal network that lies between early visual cortex and specialized cortical structures involved in visually-guided action, somatosensation, spatial audition, navigation, and spatial working memory. The type of visual information required by these processes is very general. For example an observer’s hand and the target of a reaching movement can appear in any retinotopic positions and the occipitoparietal network must still create an accurate map of their relative positions to effectively guide the action. The need to represent these sorts of relationships naturally leads to the formation of coordinate systems and general reference frames. Thus, the dorsal pathway specializes in capturing arbitrary and dynamic spatiotemporal relationships between multiple items. Over time, however, the occipitoparietal cortex also contributes to the long-term representation of non-arbitrary spatiotemporal relationships as demonstrated by findings of apraxias[4] and tool-selective regions[283] localized within the posterior parietal cortex.. This framework has the advantage of parsimoniously incorporating a number of non-visual functions associated with the dorsal pathway (e.g. number[284], sequences[285], melody[286], prosody[287]).
Is the ventral visual pathway a recurrent network?
However, there is now a wealth of anatomical evidence suggesting that the ventral visual pathway is actually a complex recurrent network. V1 projects directly not just to V2, but also to V3[24], V4[25, 28], and MT[29–32]. Thus, visual information from V1 can reach TEO in two steps via V2, V4, or MT[16, 19, 25], violating a strict serial hierarchy at even the earliest stages of visual processing. There are also direct projections between V4d and TEpd[25] and between TEOd and TEad[16, 20, 33] that bypass the intermediate regions (Fig. 3A). In addition, there are unidirectional, nonreciprocal projections from putative late stages in the pathway to early stages (Fig. 3B). Finally, while the laminar structure of projections has been used to determine levels in the hierarchy, projections beyond V1 to V2 do not strictly follow those rules, with feedforward connections terminating instead across a broad range of lamina in the target areas. For example, connections from TEO to TEpd/TEad and from TEad/TEav to STSv/f terminate throughout all 6 cortical layers[20, 34].
