Central vision pathways Flashcards
Main pathway for input to visual cortex is to this
Lateral geniculate nucleus (of thalamus)
This describes the ventral two layers of the lateral geniculate nucleus
Receives input from M retinal ganglion cells
Movement (high temporal resolution)
Magnocellular
This layer of the lateral geniculate nucleus functions in movement (high temporal resolution)
Magnocellular
Magnocellular layers of the lateral geniculate nucleus receive input from these cells
M retinal ganglion cells
Parvocellular layers of the lateral geniculate nucleus receive input from these cells
P retinal ganglion cells
This describes the superior 4 layers of the lateral geniculate nucleus
Form and color (high spatial resolution)
Parvocellular
These layers of the lateral geniculate nucleus function in form and color (high spatial resolution)
Parvocellular
This layer of the lateral geniculate nucleus receives input from P retinal ganglion cells
Parvocellular
Koniocellular layers of the lateral geniculate nucleus receive input from these cells
K ganglion cells
This layer of the lateral geniculate nucleus has a role in color vision, carrying input from short wavelength cones
Koniocellular pathway (interlaminar)
Magnocellular layers of the lateral geniculate nucleus carry information on this
Movement
Parvocellular layers of the lateral geniculate nucleus carry information on this
Form and color
Koniocellular layers of the lateral geniculate nucleus carry information on this
Color vision
This target of projections of the retinal ganglion cells is heavily involved in saccadic eye movements
Superior colliculus
Retinal ganglion cells also project directly to the superior colliculus and form a map of the contralateral or ipsilateral visual field?
contralateral
Cells from the superior colliculus project through this to cerebral cortex forming an indirect pathway to the cortex from the retina
“Blindsight”
Pulvinar nucleus (of the thalamus)
The suprachiasmatic nucleus is located within the hypothalamus, at the base of this
Diencephalon
Pretectum is located within this
Midbrain
This structure is the initial component of the pupillary light reflex pathway
Pretectum
Pretectum is the initial comnponent of this reflex pathway
Pupillary light reflex
Do superior projections carry information about the superior or inferior visual field?
Inferior
Are superior or inferior fibers of the optic radiation referred to as Meyer’s loop?
Inferior fibers
(carrying info about superior visual field)
Inferior fibers of the optic radiation sweep around this structure
Lateral ventricle
(within the temporal lobe)
Where do the inferior and superior fibers of the optic radiation end up on?
Inferior/superior banks of the calcarine sulcus (within the occipital lobe)
Does the superior portion of calcarine sulcus have information on the superior or inferior visual field?
Inferior
Macular sparing can occur in lesions to striate cortex (V1), due to these two reasons
1: large area of V1 dedicated to central vision
2: blood supply to foveal region involves PCA (majority) and MCA
Blood supply to the fovea is mostly by this artery
PCA
(MCA supplies a little)
Lesions prior to the optic chiasm (retina or optic nerves) cause ipsilateral or contralateral monocular deficits?
always ipsilateral to lesion
This term describes partial loss in visual field
Can be hemi or quadrant
Scotoma
This term describes total loss of vision
Anopia
Monocular deficits (such as anopia and scotoma) are associated with lesions prior to this structure
Optic chiasm
(e.g. retina or optic nerves)
Binocular visual field deficits have to be at the level of this or farther
Optic chiasm
Heteronymous describes different visual fields in each eye, and only occurs with lesions to this
Optic chiasm
This describes having different visual field losses in each eye
Only occurs with lesion to optic chiasm
Heteronymous deficit
This describes having the same visual field deficits in both eyes
Homonymous
(can be contralateral hemianopia or quadrantanopia - macular sparing can occur with both)
A right superior quadrantanopsia occurs with lesion to this
Meyer’s loop
(inferior optic projections)
Right inferior quadrantanopsia occurs with lesion to this
Superior projection of optic radiation
Can macular sparing occur with compression of optic nerve?
Yes
Sense of depth that results from viewing the world with two eyes
Stereopsis
Types of neurons within V1 visual areas that are sensitive to disparity, and are located beyond the point of focus
Far cells
Types of neurons within V1 visual areas that are sensitive to disparity, and are located closer than the point of focus
Near cells
Types of neurons within V1 visual areas that are sensitive to disparity, and are located in the fovea
Tuned zero cells
This stream of cortical vision functions in vision for action
Dorsal stream
This stream of cortical vision functions in vision for perception
Ventral stream
The dorsal stream of cortical vision travels from occipital lobe to this
Posterior parietal cortex
The ventral stream of cortical vision travels from occipital lobe to this
Inferior temporal cortex
Achromatopsia occurs due to damage of this brain structure
Fusiform gyrus (V4)
Akinetopsia occurs due to damage of this brain structure
Middle temporal cortex (V5)
Visual form agnosia occurs due to damage of this brain structure
Lateral occipital
Simultanagnosia occurs due to damage of this brain structure
Parietal lobe
Prosopagnosia occurs due to damage of this brain structure
Fusiform gyrus
Word agnosia occurs due to damage of this brain structure
Anterior occipital lobe
Damage to fusiform gyrus causes these 2 visual agnosias
Achromatopsia
Prosopagnosia
Damage to V5/ medial temporal lobe causes this visual agnosia
Akinetopsia
Is cerebral achromatopsia a ventral or dorsal stream lesion?
Ventral
Cerebral achromatopsia is often caused by a bilateral infarction of this artery distribution
PCA
Bilateral infarction of posterior cerebral artery distribution can cause damage to the lingual and/or fusiform gyri (V4), leading to this visual agnosia
Cerebral Achromatopsia
This is an impaired ability to smoothly perceive motion
Akinetopsia
Akinetopsia is likely a result of cortical damage to the ventral or dorsal stream?
Dorsal
(e.g. the middle temporal cortex)
This is substantial impairment at recognizing visually presented stimuli (objects, drawings)
Visual form agnosia
Carbon monoxide poisoning affecting lateral occipital regions can cause this visual defect
Visual form agnosia
(Impairment in shape discrimination and object identification)
Visual form agnosia involves lesions to the ventral or dorsal stream?
Ventral
This is an inability to see more than one object in an array
Simultanagnosia
These are impairments of the structural description system
Failure of object recognition, despite visual processing that can result in accurate figure copying
Associative agnosias
