chapter 4 Flashcards
1
Q
optic chiasm
A
- location in the optic tract where the optic nerve from each eye splits in half with nasal retinae crossing over and temporal retinae staying on the same side of the optic tract
2
Q
optic tract
A
- the optic nerve starting at the optic chiasm and continuing into the brain
3
Q
contralateral representation of visual space
A
- arrangement whereby the left visual world goes in to the right side of the brain and the right visual world goes to the left side of the brain
4
Q
ipsilateral organization
A
- same side organization, in the visual system, the temporal retina projects to the same side of the brain
5
Q
lateral geniculate nucleus (LGN)
A
- bilateral structure (one in each hemisphere) in the thalamus that relays information from the optic nerve to the visual cortex
6
Q
magnocellular layers
A
- layers of the lateral geniculate nucleus with large cells that receive input from M ganglion cells (parasol retinal ganglion cells)
- layers 1 and 2
7
Q
parvocellular layers
A
- layers of the lateral geniculate nucleus with small cells that receive input from P ganglion cells (midget retinal ganglion cells)
- layers 3-6, smaller
8
Q
koniocellular layers
A
- layers of the lateral geniculate nucleus with very small cells that recieve input from K ganglion cells (bistratified retinal ganglion cells)
-6 smallest
9
Q
LGN facts
A
- each layer receives input from only one eye
- contralateral eye, magnocellular 1, parvocellular 4 6
- ibsilateral eye, magnocellular 2, parvocellular 3 5
10
Q
superior colliculus
A
- structure located at the top of the brain stem beneath the thalamus
- controls eye movements
11
Q
smooth pursuit eye movements
A
- voluntary tracking eye movements
12
Q
saccades
A
- most common and rapid of eye movements
- sudden moves to look from one object to another
13
Q
primary visual cortex, VI, striate cortex area 17
A
- area of the cerebral cortex that receives input from the lateral geniculate nucleus located in the occipital lobe and responsible for early visual processing
14
Q
retinotopic map
A
a point by point relation between the retina and V1
15
Q
cortical magnification
A
- allocation of more space in the cortex to some sensory receptors than to others
- the fovea has a larger cortical area than the periphery
16
Q
cerebral cortex lobes
A
- frontal lobe
- temporal lobe
- parietal lob
- occipital lobe
17
Q
frontal lobe
A
- thinking, planning, speaking, motor functions
18
Q
temporal lobe
A
- memory, language comprehension, auditory perception
19
Q
parietal lobe
A
- attention, somatosensory perception
20
Q
occipital lobe
A
- visual cortex, vision
21
Q
simple cells
A
- V1 neurons that respond to stimuli with particular orientations to objects within their receptive field
- the preferred orientation of a simple cell is the stimulus orientation that produces the strongest response
22
Q
orientation turning curve
A
- graph that demonstrates the typical response of a simple cell to stimuli or different orientations
23
Q
complex cells
A
- neurons in V1 that respond optimally to stimuli with particular orientations
- unlike simple cells, respond to variety of stimuli across locations and to moving stimuli
24
Q
end stopped neurons
A
- neurons that respond to stimuli that end within the cell’s receptive field
25
Q
ocular dominance column
A
- column within V1 that is made up of neurons that receive input from only the left eye or only the right eye
26
Q
orientation column
A
- a column within V1 that is made up of neurons with similar responses to the orientation of a shape presented to those neurons
27
Q
blobs
A
- group of neurons within V1 that are sensitive to color
28
Q
interblobs
A
- groups of neurons that are sensitive to orientation in vision
29
Q
benefit of slit pupils
A
- adjust pupil size more than humans can
- see well night and day
30
Q
tapetum
A
- reflective layer behind the receptors of nocturnal animals that bounces light not caught by receptors back into the retina
31
Q
nautilus eyes
A
- pinhole eye, no lens or cornea, small pupil its small pupil
32
Q
compound eyes
A
- eye that does not have a single entrance but is made up of many separate components called ommatidia
- insects
33
Q
function of argus II prosthesis
A
- vision prosthesis, video camera mounted on eyeglasses
- send images to a chip placed on the retina
- chip stimulates retinal ganglion cells to create a rough visual field for patients with profound retinitis pigmentosa.
- only 20 degree visual field, limited acuity, unclear, hardware stability issues
34
Q
brainport system
A
- camera on glasses and a pad on the tongue
- camera converts visual signals to tactile ones, and the pad vibrates a pattern on the tongue, which patients can learn to interpret as visual information.
35
Q
artificial silicon retina vs argus II
A
- artificial silicon retina directly implants visual sensors into the retina without the need for external cameras
- not approved for general use
36
Q
stem cells vision restoration
A
- regrow photoreceptor cells in patients with retinal diseases
- not proven yet
37
Q
hyper column
A
- a 1mm block of v1 containing both the ocular dominance and orientation columns for a particular region in visual space
38
Q
extrastriate cortex (secondary visual cortex)
A
- collective term for visual areas in the occipital lobe other than v1
39
Q
v2
A
- after information leaves V1 it travels to other areas in the occipital cortex (extrastriate cortex)
- second area in the visual cortex that received input, starts visual associations rather than procession the input
40
Q
3 regions of v2
A
- blobs to thin stripes, color
- 4B to thick stripes, motion
- interblobs to interstripes, shape and position
41
Q
ventral pathway
A
- what
- starts with midget and bistratified retinal ganglion cells
- continues through the visual cortex into the the inferotemporal cortex in the temporal lobe, object identification and color vision
42
Q
dorsal pathway
A
- where
- starts with parasol retinal ganglion cells
- through the visual cortex into the parietal lobe, location and movement
43
Q
mishkin et al. (1983)
aim
A
- investigate the distinct roles of the dorsal (spatial recognition) and ventral pathways (object recognition)
- assess how damaging specific areas of the brain affects the monkeys’ ability to perform tasks
44
Q
mishkin et al. (1983)
procedure
A
- monkeys trained to perform 2 tasks, landmark and object
- landmark, select container closer to a specific landmark in the room
- object, select container covered by a specific object
- lesioned either inferotemporal cortex (associated with the ventral pathway), parietal lobe (associated with the dorsal pathway)
- monkeys completed task before and after surgery
45
Q
mishkin et al. (1983)
results
A
- damage inferotemporal cortext, normal performance landmark, impaired object
- damage parietal lobe, normal object task, impaired landmark
46
Q
mishkin et al. (1983)
conculsion
A
- inferotemporal cortex plays a role in object recognition (“what”).
- parietal lobe is plays a role in spatial recognition (“where”).
47
Q
mishkin et al. (1983)
evaluation
A
- ethical concerns of animal research
- findings backed up by other research
48
Q
held and hein (1963)
aim
A
- investigate how active vs passive visual experience impacts development in kittens
- explore the effects of visual deprivation on the receptive fields of neurons in the visual cortex and the role of innate organization and experience in the development of the visual system.
49
Q
held and hein (1963)
procedure
A
- kittens seperated into 2 groups, both raised in all dark environments, later exposed to visual stimuli (vertical stripes)
- group 1, actively explored their environment
- group 2, passively yoked to the first group, experiencing the same stimuli without active participation
- given tests on a variety of visual tasks
- receptive field of neurons in the kittens’ primary visual cortex (V1) were examined after the deprivation period
50
Q
held and hein (1963)
results
A
- active kittens developed normal visual abilities, performed better on tasks
- passive kittens showed slowed visual development and performed poorly on the same tasks
51
Q
held and hein (1963)
conclusion
A
- early visual experience is essential for the development of normal neural organization in the visual cortex
- Deprivation during critical early periods can cause permanent changes in neural structure, emphasizing the importance of early sensory input.
- cortex grow rapidly in infancy but are pruned later in childhood, same as animals
52
Q
held and hein (1963)
evaluation
A
- ethical concerns of animal experiments, unable to be replicated on humans
53
Q
blindsight
A
- presence of visual abilities even though a person experiences blindness because of damage to V1
54
Q
conjugate gaze palsies
A
- neurological disorders that affect the ability of the eyes to coordinate their movements
- horizontal and vertical directions
