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).
Where is ventral visual pathway?
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 is the ventral visual stream specialized for?
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 is the dorsal visual pathway?
Dorsal visual pathway: this pathway
extends from the primary visual cortex (V1) in the occipital lobe to the parietal lobe
. The dorsal pathway is subdivided by the intraparietal sulcus (IPS) into several main sectors including the superior parietal lobule, inferior parietal lobule, and the supramarginal gyrus.
What is the function of dorsal pathway?
a pathway that
carries visual information from the primary visual cortex to the parietal lobe
.
What happens if the ventral stream is damaged?
Patients with damage to the ventral stream are
typically unable to perceive the size, shape, and orientation of objects
. Remarkably, however, some of these patients continue to show normal preshaping and rotation of the hand when they reach out to grasp the very objects whose forms they fail to see.
What does damage to the ventral visual pathway do?
Damage to the ventral visual pathway can produce
a set of deficits termed visual agnosias
. Visual agnosias are impairments in the perception and/or recognition of objects. … They can perceive parts of an object, but cannot group the parts together to recognize a full object.
What is the visual pathway?
The visual pathway consists of
the retina, optic nerves, optic chiasm, optic tracts, lateral geniculate bodies, optic radiations, and visual cortex
. The pathway is, effectively, part of the central nervous system because the retinae have their embryological origins in extensions of the diencephalon.
What is the visual agnosia?
General Discussion. Primary visual agnosia is
a rare neurological disorder characterized by the total or partial loss of the ability to recognize and identify familiar objects and/or people by sight
. This occurs without loss of the ability to actually see the object or person.
What are the two visual systems?
This two-visual-systems hypothesis (TVSH) proposes that the
ventral stream of visual pathways in the cerebral cortex
, which delivers up our visual experience of the world, works in an allocentric frame of reference, whereas the dorsal stream, which mediates the visual control of action, uses egocentric frames of …
What is the difference between the ventral and dorsal pathways?
The ventral stream (or “vision-for-perception” pathway) is believed to mainly subserve recognition and discrimination of visual shapes and objects, whereas the dorsal stream (or “vision-for-action” pathway) has been primarily associated with
visually guided
reaching and grasping based on the moment-to-moment analysis …
What happens if the dorsal pathway is damaged?
If either the dorsal or ventral stream is damaged, this leads to
dissociable behavioural deficits
. For example, patients with optic ataxia have lesions in parietal areas, which are part of the dorsal stream. They have deficits in reaching and grasping objects, but are able to visually discriminate different objects.
What are the two main visual pathways in primates?
Two Visual Pathways in Primates Based on Sampling of Space: Exploitation and Exploration of Visual Information. Evidence is strong that the visual pathway is segregated into two distinct streams—
ventral and dorsal
.
What is form agnosia?
Visual form agnosia is
a severe disorder of visual recognition resulting from extrastriate lesions in occipital and temporal cortex
. Despite preserved visual acuity and minor visual field defects, patients with visual form agnosia are severely impaired in shape and form discrimination.
How do the two visual streams interact with each other?
The ventral stream, passing from primary visual cortex (V1) through to inferior parts of the temporal lobe, is considered to mediate the transformation of the contents of the visual signal into the mental furniture that guides memory, recognition and conscious perception.
What is dorsal and ventral side?
The main difference between dorsal and ventral is the area of the body to which they refer. In general,
ventral refers to the front of the body, and dorsal refers to the back
. … Similarly, for the feet, the dorsal side is the top of the foot, or the area facing upwards when standing upright.
