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 pathway leading from the striate cortex to the parietal lobe?
The dorsal stream, which includes the middle temporal area , leads from striate cortex into the parietal lobe. This system is thought to be responsible for spatial aspects of vision, such as the analysis of motion, and positional relationships between objects in the visual scene (Figure 12.17).
What is the main pathway between the eye and the cortex?
The optic nerve is the pathway that carries the nerve impulses from each eye to the various structures in the brain that analyze these visual signals.
What is the order of 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 cortical pathway?
The cortical motor pathway consists of four regions of the cerebral cortex (primary motor cortex, posterior parietal cortex, premotor cortex, and supplementary motor cortex) whose neuronal cell bodies are located in layer V (five) and whose projections are involved with the execution of muscle contraction largely on ...
What is the pathway and where pathway?
In the currently prevailing view, the different maps are organised hierarchically into two major pathways, one involved in recognition and memory (the ventral stream or ‘what' pathway) and the other in the programming of action (the dorsal stream or ‘where' pathway).
What does the ventral pathway do?
a pathway that carries visual information from the primary visual cortex to the temporal lobe . 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.
What are the 3 visual pathways?
- The retina.
- The optic nerve (CN II)
- The optic chiasm and tract (reticulogeniculate tract)
- The pretectal connections of the visual pathway.
- The lateral geniculate body.
- Optic radiation and visual cortex.
What is pupillary pathway?
The pupillary light reflex neural pathway on each side has an afferent limb and two efferent limbs . The afferent limb has nerve fibers running within the optic nerve (CN II). ... The efferent limb is the pupillary motor output from the pretectal nucleus to the ciliary sphincter muscle of the iris.
Where does the visual pathway begin?
The optic pathway begins in the retina , which is a complex structure made up of ten different layers. Each layer serves a distinct function. The photoreceptor layers consist of the rods and cones, which generate action potentials with the help of rhodopsin through photosensitive cycles.
What is the first order neuron in the visual pathway?
In summary, the visual pathway involves three consecutive neurons: The first neuron represents the bipolar cells of the retina and receives visual information from the neuroepithelial cell of the retina (e.g. rods and cones). The second neuron corresponds to the ganglion cell of the retina.
What is the Geniculostriate pathway?
geniculostriate pathway (plural geniculostriate pathways) (anatomy) A group of axons that connect neurons in the lateral geniculate nucleus to the primary visual cortex .
What is the visual pathway from the eyes to the occipital lobe?
The visual pathways comprise the optic nerve , optic chiasm, optic tract, optic radiation and the visual cortex in the occipital lobes. Nerve impulses arising in the retina travel via the optic nerve to the optic chiasm.
What are cortical and subcortical pathways?
Among cortical areas (shown in red) are OFC and ACC. ... The visual and emotional systems are extensively interconnected, especially at the subcortical level, where the superior colliculus is connected to the amygdala via the pulvinar.
What is the magnocellular pathway?
The magnocellular pathway is one of the three primary subcortical pathways (magnocellular, parvocellular, and koniocellular pathways) leading from the retina to visual cortex via the lateral geniculate nucleus (LGN).
What does cortico cortical mean?
Filters . (anatomy) That connects one cortex with another .
Where is the ventral 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 does the ventral pathway and the dorsal pathway indicates?
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 ...
Where is the temporal area?
The temporal lobes sit behind the ears and are the second largest lobe. They are most commonly associated with processing auditory information and with the encoding of memory.
What is the when pathway?
This pathway is lateralized in the right hemisphere and is specialized at performing attention-mediated temporal processing at intermediate time scales. This is a core function that enables, for instance, the discrimination of two identical events that occur at the same point in space but at different time intervals.
Where 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 type of processing is accomplished by the dorsal path?
The dorsal stream processes information about the “where” of the visual stimulus (Figure 15.10). Damage the dorsal visual association cortex results in deficits in spatial orientation, motion detection and in guidance of visual tracking eye movements.
What is the pathway of the optic nerve?
The optic pathway includes the retina, optic nerve, optic chiasm, optic radiations, and occipital cortex (see figure Higher visual pathways. Damage along the optic pathway causes a variety... read more ). Damage along the optic pathway causes a variety of visual field defects.
What is the secondary visual pathway?
Tutorial 24: Brain Visual Pathways. ... This secondary pathway mediates the ability to localize visual objects in space . In addition, along this pathway, visual information is integrated with auditory and somatosensory information and used to control movements made to objects of interest.
How visual information is transmitted to the brain?
The optic nerve , a cable–like grouping of nerve fibers, connects and transmits visual information from the eye to the brain. The optic nerve is mainly composed of retinal ganglion cell (RGC) axons. ... having a long axon that extends into the brain via the optic chiasm and the optic tract. synapsing with the LGN.
What is afferent pupillary pathway?
The afferent pupillary pathway comprises the retinal photoreceptors , the bipolar cells and the retinal ganglion cells whose axons form the optic nerve. Temporal fibers run ipsilaterally while the nasal fibers cross to the contralateral side in the optic chiasm.
What is meant by the visual pathway where is the blind spot and what causes it?
blind spot, small portion of the visual field of each eye that corresponds to the position of the optic disk (also known as the optic nerve head) within the retina . There are no photoreceptors (i.e., rods or cones) in the optic disk, and, therefore, there is no image detection in this area.
How is the visual pathway from the eye different from that of the ear?
How is the visual pathway from the eye different from that of the ear or hand? Each eye is not primarily connected to one hemisphere only . Briefly explain split-brain research.
In what order does visual information pass through the retina quizlet?
Light passes through the retina in this order: ganglion cells > bipolar cells > cones .
How do you initiate the pupillary reflex quizlet?
This reflex is initiated by gently stroking the skin at the hair line on the back of one side of the subject's neck . This results in the dilation of the pupil on the ipsilateral side of the stimulus. The reflex is not consensual because the contralateral pupil does not dilate.
What nerve dilates the pupil?
Cranial nerves III (CNIII) (oculomotor), IV (trochlear), and VI (abducens) control the position of the eyeballs; CNIII influences the position of the eyelids and the size of the pupils.
What is the direction of information flow from the retina and leaving the eye?
The optic chiasm from each of the retina moves towards the brain and crosses over. Due to the crossing over of the optic chiasm, the visual signals from the right eye reaches the left hemisphere of the brain, and those of the left eye reaches the right hemisphere.
What happens to the optic nerve pathway at the optic chiasm?
At a structure in the brain called the optic chiasm, each optic nerve splits, and half of its fibers cross over to the other side. Because of this anatomic arrangement, damage along the optic nerve pathway causes specific patterns of vision loss .
What are 1st 2nd and 3rd order neurons?
First Order Neurons: Detect a stimulus and transmits a signal to the spinal cord . Second Order Neurons: Continues as far as the gateway-the thalamus- at the upper end of the brainstem. Third Order Neurons: Carries the signal the rest of the way to the sensory region of the cerebral cortex.
What does the Tectopulvinar pathway do?
Function. The tectopulvinar pathway is a fast-acting pathway that provides the viewer with information on the absolute spatial information of objects .
What is the name for the optic radiations that run through the temporal lobe on the way to the striate cortex?
Some of the optic radiation axons run out into the temporal lobe on their route to the striate cortex, an anomaly called Meyer's loop (see Figure 12.7). Meyer's loop carries information from the superior portion of the contralateral visual field.
What does the lingual gyrus do?
The lingual gyrus is a structure in the visual cortex that plays an important role in the identification and recognition of words . Studies have implicated the lingual gyrus as being involved in modulating visual stimuli (especially letters) but not whether or not the stimulus was a word.
What are subcortical pathways?
Subcortical pathways extract spectral, temporal, and spatial cues from complex sounds that originate from multiple sources . • Auditory processing in subcortical areas demonstrates neural selectivity for complex sounds observed in cortical networks.
What is subcortical region?
Subcortical structures are a group of diverse neural formations deep within the brain which include the diencephalon, pituitary gland, limbic structures and the basal ganglia. ... They act as information hubs of the nervous system, as they relay and modulate information passing to different areas of the brain.
What does the superior colliculus do?
The superior colliculus (SC) is a multisensory midbrain structure that integrates visual, auditory, and somatosensory spatial information to initiate orienting movements of the eyes and head toward salient objects in space .
