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Exam 4 Chapter 6...
Physiological Psychology LSU Vision (Chapter 6)
103
Physiology
Undergraduate 4
10/29/2013

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Term
sensory transduction
Definition
monitors stimuli and these sensory events are transferred into changes in the cells membrane potential
Term
which lenghts of light spectrum can human see
Definition
380-760nm
Term
how does colors disperse along the light spectrum we see
Definition
roy g biv
760-380nm
red is 800nm
violent is 400nm
Term
what determines hue
Definition
wavelength
Term
how does brightness describe the light and what happens to light with decreasing brightness
Definition
its a measure of intensity of light. with decreasing brightness the color goes to brown then black
Term
what is saturation of light
Definition
the relative purity of the light
Term
what are three layers of eye
Definition
sclera
pigment epithelium
retina
(goes from outside to inside)
Term
sclera
Definition
-tough opaque outer coating of eye but at front of eye is is transparent
-for protection
Term
saccadic movements
Definition
jerky movement of eyes when scanning a visual scene
Term
pursuit movement
Definition
movement eyes make to maintain an image of a moving object on the fovea
Term
how do you make you eyes move more slowly
Definition
looking at your finger while you moving it around
Term
what regulates the amount of light that enters the eye
Definition
size of the pupil
Term
process of accommodation
Definition
the changes in shape of the lens to focus on images of near or distant objects on the retina
Term
ciliary muscles function
Definition
similar to a sphincter muscle. circular band of muscle around the lens that is attached by ligaments and changes the shape of lens for accommodation
Term
pigment epithelium
Definition
-contains blood vessels and nourishes photo receptors
-contains melanin
-at anterior has muscle groups which allow eye to adjusted for change in amount of light and diffraction and focal point
Term
why doesn't light just reflect all around inside eye
Definition
-the pigment in form of melanin which adsorbs light
Term
why do albinos have poor vision
Definition
light bounces around and lose ability to code topography of where light is on retina so its hard to tell where light is coming from
Term
photoreceptors
Definition
-receptor cells (rods and cones) of the retina
Term
how and what muscle is in iris
Definition
-smooth muscles layer on top of each other and increase the size of the pupil
Term
types of muscles in iris
Definition
dilator muscles
sphincter muscles
Term
dilator muscle
Definition
-muscles radiate outwards like spokes on bicycle from the pupil
-adrenergic
-enlarges pupil
Term
sphincter muscle
Definition
-concentric circles of muscle around pupil
-cholinergic
-shrinks pupli
Term
shape of lens when looking close or far away
Definition
lens is flat when looking far away
Term
how does lens grow
Definition
-accretion where by new tissue is added to outside
Term
how does way lens grow effect vision
Definition
new tissue just grows over old tissue and eventually lens can't get rid of waste or receive nutrients as well so this causes cataracts and decreases accommodation for distance.
Term
what does retina contain
Definition
rods and cones or also called photoreceptors
Term
how is light slowed through lens
Definition
-light is slowed through more dense material
Term
refractive index
Definition
measure of a material to slow light i.e. regular speed of light divided by slowed speed. the higher the number the slower the light is
Term
what part of eye makes up 80 percent of the refractory power
Definition
cornea
Term
best way for lens to refract light more
Definition
-change angle of incidence so lens becomes more curved to maintain focal length if object gets very close
Term
how is farsightedness qualified in a person's eye
Definition
focal point is past the fovea
Term
location of optic disk
Definition
retina
Term
where is the blind spot in vision
Definition
produced by the optic disk
Term
why is there a blind spot in vision
Definition
there are no receptors in the optic disk
Term
what runs through the optic disk
Definition
-where the axons conveying visual info gather together and leave the eye through the optic nerve
-emergence of 2nd cranial nerve
-blood vessels coming in and out
Term
most prevalent in the central retina and fovea
Definition
cones
Term
sensitive to moderate to high levels of light
Definition
cones
Term
provide information about hue
Definition
cones
Term
provide excellent acuity
Definition
cones
Term
most prevalent in the peripheral retina and not in fovea
Definition
rods
Term
sensitive to low levels of light
Definition
rods
Term
provide only monochromatic information
Definition
rods
Term
provide poor acuity
Definition
rods
Term
structure of rods and cones
Definition
outer segment connected by a cilium to an inner segment which contains the nucleus
Term
lamellae
Definition
thin plates of membrane in the outer segment of rods and cones
Term
where is the photopigment found
Definition
in the membrane of the lamellae
Term
what is contained inside inner segment of rods and cones
Definition
nucleus
ribosomes
mitochondria
Term
what is the function of inner segment of rods and cones
Definition
produce photopigment
Term
synaptic segment
Definition
place of contact between photodetectors and bipolar cells
Term
what is best way to describe light when accounting f or how light gets into rods and cones
Definition
particle nature
Term
What word to write on exam for bonus
Definition
Wade
Term
where are horizontal cells located
Definition
retina
Term
where are amacrine cells located
Definition
retina
Term
horizontal cells
Definition
transmit info in a direction parallel to the surface of the retina and combine messages from adjacent photoreceptors and outer processes of bipolar cells
Term
amacrine cells
Definition
transmit info in a direction parallel to the surface of the retina and combine messages from adjacent ganglion cells and inner processes of biopolar cells
Term
what makes up photopigment
Definition
opsin a protein and retinal a lipid
Term
layers of retinal circuitry
Definition
start:ganglion cell layer
then:bipolar cell layer
end:photoreceptor layer
Term
rhodopsin
Definition
-consists of rod opsin and retinal
Term
process of rhodopsin
Definition
-starts off bent (11-cis retinal) in the dark and the light straightens it out and it decomposes into rod opsin and retinal which produces the change in the membrane potential of the photoreceptor
Term
types of cone opsin
Definition
red
blue
green
Term
is there action potential for rods and cones
Definition
no
Term
how is potential described for retinal circuitry
Definition
continuous change in the difference in outer segment and synaptic terminal
Term
describe change in electric potential in rod
Definition
-wall of inner segment has na-k pump
-na enters outer segment in the dark and pump maintain inner segment at -30mv (depolarization) then light closes na channel in outer segment so it goes to -70mv(hyper polarization)
Term
what is released in dark in rods and what is affect on the retinal circuitry
Definition
glutamate is released and has inhibitory effect on bipolar and excitatory on ganglion cell
Term
optic path out of ganglion cell
Definition
-cranial nerve 2 goes to the optic chiasm
-and go down optic tract to synapse at the lateral geniculate nucleus in the thalamus
-then axon goes to synapse at occipital cortex or the striate cortex
Term
optic radiations
Definition
the pathway from the lateral geniculate nucleus to the primary visual cortex
Term
what is the function of retinal disparity
Definition
coding for depth and subtle differences in vision in each eye due to the overlap
Term
how does cranial nerve run out of retina on each eye i.e. what is wiring pattern
Definition
nasal side of right eye is for right visual field and crosses the optic chiasm
nasal side of left eye is for left visual field and crosses the optic chiasm
temporal side of right eye is for left visual field and doesn't cross
temporal side of left eye is for right visual field and doesn't cross
Term
how does nervous system extract info
Definition
simple wiring pattern similar to the senses i.e. retinotopic or topographic configuration
Term
how does a person have bitemperal hemianopsia and what is it
Definition
severe optic chiasm and get tunnel vision i.e. periphery is gone
Term
what happens if you severe left optic tract after on chiasm
Definition
the right side of each eye's vision is cut off
Term
receptive field work
Definition
plant microelectrode in a cell in vision pathway and shine light on retina and find what part of retina that cell is referring too
Term
why is vision more acute at in center of vision
Definition
there is only one ganglion cell devoted to one photoreceptor as opposed to multiple photoreceptors converging on one ganglion cell
Term
on center receptive cell
Definition
on in response to light in center and off in surroundings
Term
off center receptive cell
Definition
off in response to light in center and on in surroundings
Term
what is the function of on/off cells in life
Definition
visual reflexes and not direct role in form perception
Term
the excitation and inhibition diagram of on center cells
Definition
photoreceptor (-) bipolar (+) ganglion
Term
the excitation and inhibition diagram of off center cells
Definition
photoreceptor (+) bipolar (+) ganglion
Term
how they learned about lateral inhibition initially
Definition
by way of the limulus which had large individual lens with single photo receptor i.e ommatidium. and when light is shown on one and output went up but with light on one and simultaneously on neighboring photodectors and output decreases
Term
how does lateral inhibition help mammals
Definition
maximizes contrast
Term
what causes a gradient to form when there isn't technically one there
Definition
lateral inhibition
Term
what is the nature and design of receptor cells in horizontal configuration
Definition
1-2-3-4-5-6-7 (with light shown on 3,4,5

3 4 5 excited with 3 and 5 being most excited
2 and 6 are most inhibited
Term
how is lateral geniculate nucleus arranged
Definition
1 2
4 3
6 5
Term
which layers in lateral gen. nuc. do lower animals need to see
Definition
layer one and two
Term
what can layer one and two in lat. gen nuc do
Definition
only contrast and motion
Term
how does size of receptive field in thalamus differ from before and why
Definition
it is bigger due to convergence
Term
in cortex what format of light gives best response
Definition
gradual change in light to dark of linear arrays
Term
which layers in cortex respond monocularly
Definition
layer 4 and other 5 layers responds binocular
Term
how do hyper columns respond
Definition
particular place in space to a line with an orientation
Term
layers 1 and two prefer high or low spatial frequency
Definition
low
Term
how does visual angle work with spatial frequency
Definition
-as visual angle go down more info goes to the eye
-spatial frequency is the number of bars you have per degree of visual angle
Term
what is visual angle
Definition
angle between two adjacent bars of light when they strike the retina
Term
what type of cells exist outside layer four of occipital lobe cortex
Definition
simple
complex
hypercomplex
Term
what does simple cells respond to.
Definition
-respond to circle of light but linear array of light is better like sine wave gradients
Term
what is pattern of response for simple
Definition
+-+-+
+-+-+
+-+-+
Term
how is simple cell wired
Definition
one receptive field goes to one simple cell in cortex
Term
how is complex different from simple
Definition
it is bigger and doesn't have clear inhibitory zones and has coding for movement of bar of light
Term
how is complex cell wired
Definition
the convergence of receptive fields of multiple simple cells
Term
hyper complex inhibitory zones
Definition
---
---
+++
+++
+++
---
---
Term
what does hyper complex respond to
Definition
movement of light in particular direction
Term
visual association cortex has what two streams
Definition
dorsal
ventral
Term
ventral stream function
Definition
memory system of previous visual experiences.
with stroke to ventral then u can't recognize dogs or faces
size, shape, color, texture of objects
Term
dorsal stream function
Definition
spatial relationship like where we are in space i.e. a cognitive map
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