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ch 6-1
vision
68
Psychology
Undergraduate 1
04/08/2008

Additional Psychology Flashcards

 


 

Cards

Term
What does it mean to transduce energy?
Definition
The receptors transduce or convert energy (light) into electrochemical patterns
Term
What is receptor potential?
Definition
Local depolarization or hyperpolarization of membrane
Term
What determines the hyperpolarization of inhibition of the next neuron in a receptor potential?
Definition
The strength of the receptor potential
Term
what is the law of specific nerve energies?
Definition
Nerve always conveys same type of information- action potential interpreted as certain stimulus
ex. rubbing eyes fires visual receptors- excites and is perceived as light
Term
Amacrine cells
what are they?
Definition
Amacrine cells control ability of ganglion cells to respond to shapes and movements
Term
What are the parts of the Retina and where os the Retina located?
Definition
- REtina is located at the baCK of the eye
- Comprised of
Macula - center of human retina
Fovea-
Term
What is the FOVEA and Where is it located
Definition
Located in center of Macula
Allows for detailed acute vision
High density of receptors
Nearly free of blood vessels and ganglion axons
Term
What part of the eye is nearly free of blood vessels and ganglion axons
Definition
The Fovea
Term
The Receptors in the Fovea are connected to what?
Definition
Single bipolar cell and ganglion cell (midget ganglion)
Term
What are midget ganglion cells?
Definition
in the fovea of humans, called midgests because each is small and responds to just one single cone, has direct line to brain
Term
Receptors outside fovea do what?
Definition

-increased number of of receptors converge on bipolar and bipolar cells

-decreased acuity

-Increase vision under low light conditions 

Term
what are two kids of Verterbrate photoreceptors
Definition
Rods and Cones
Term
Name the Specs of the Rods
Definition
-Abundant in periphery
- respond to faint light
- 120 million per retina 
Term
Name the specs of the cones
Definition
-Abundant in Fovea
-For color vision
-High acuity
- 6 million per retina 
Term
photopigment
Definition
-Contained by both rods and cones
-chemicals that release energy when struck by light
- have 11 cis-retinal bound to protiens called opsins 
Term
When is the 11 cis retinal stable?
Definition
In the dark
Term
What does light energy convert 11 cis retinal to?
Definition
All-trans retinal- light is absorbed energy is released
Term
Trichromatic Theory
Definition
You see in three different colors because three differnt cones are sensitive to 3 differnt wavelengths, other colors are a combination of the three: blue, yellow, and red
Term
Opponent Process Theory
Definition
percieve color in terms of paired opposites
- bipolar cells may be xcited by one wavelength and inhibited by another 
Term
Retinex Theory
Definition
cortex compares info from various parts of the retina to determine color for each area
ex rubix cube takes away comparisons 
Term
Color Deficiency- what is is?
Definition
Impairment in percieving color differences
- caused by abnormal cones
- most common between red and green cones
 
Term
What chromosome carries the color deficieny gene?
Definition
Carried on the x chromosome
Term
what are Magnocellular Ganglionic Neurons
Definition
Input from rods
responsive to movement
big cell bodies 
Term
what are Parvocellular ganglionic neurons
Definition
small cell bodies
color detail and still or slow object
input from cones 
Term
Koniocellular gnaglionic neurons
Definition
small cell bodies
found throughout retina 
Term
what is a Hemiretina?
Definition
Half of a retina
 
Term
Lateral Geniculate Nucleus
Definition
-Thalamic nucleus specialized for vision
-destination for most gnaglionic cell axons
-sends axons to parts of occipital cortex and other areas of the thalamus 
 
Term
what is the primary visual cortex? V1?
Definition
Recieves info from lateral geniculate nucleus
-1st stage of visual processing 
Term
Name the cells of the visual cortex
Definition
simple cells- found primarily
fixed excitatory and inhibitory zones
- bar shapes and edge shaped receptive fields outnumber diagonal 
Term

Compex cells

where are they located?

 

Definition

-found in v1 or v2

 -large receptive field lackingfixed excitatory and inhibitory zones

 

Term
what do complex cells respond to?
Definition
prefer stimulus moving perpendicular to axis
Term
what are hypercomplex cells?
Definition
similar to complex cells but with strong inhibitory fields at the end of visual field
Term
The visual cortex has:
Definition
- columnar organization 
Term
Cells of visual cortex process what?
Definition
simliar information such as oreintation and source
- may have feature detectors- neurons whose response indicate prescence of particular feature or stimuli 
Term
What is shape constancy?
Definition
ability to recognize object's shape despite changes in direction or size
Term
What can damage in pattern pathways in cortex lead to?
Definition
deficits in object recognition
Term
what is visual agnosia?
Definition
inablity to recognize faces
- due to damage to pattern pathway in temporal cortex
Term
what is prosopagnosia?
Definition
inablity to recognize faces
due to damage in the fusiform gyrus of inferior temporal cortex 
Term
What does the Middle temporal cortex or v5 respond to?
Definition
stimulus moving in particular direction
Term
what do cells in the Medial Superior Temporal (MST) cortex respond to?
Definition
exapnsion and contraction or rotation of visual stimulus
ex. star wars effect- stars going past 
Term
What areas recieve direct input from the magnocellular path?
Definition
MT and MST
Term
What does the magnocellular path of the MT MST detect?
Definition
overal patterns including movement over large areas of the visual the visual field
Term
What do parvocellular paths of the MT MST detect?
Definition
disparity between views of teh left and right eyes, important for distance
Term
What does the Fusifor face area do?
Definition
specialized for faces- brittany spears neurons
Term
how many days after birth does a newborn recognize faces?
Definition
about 2 days
Term
what does lack of early stimulation do? in ONE eye? in Both eyes?
Definition
One eye- synapses in visual cortex become gradually unresponsive to input from that eye
 
Both eyes- cortical responses become sluggish but do not cause blindness 
Term
what are the sensitive/ critical periods?
Definition
Time during lifespan when experiences havestrong  long lasting effect
- time when GABA becomes widely availiable
-ends with onset of chemicals the inhibit  axonal growth
-requires both inhibition and excitation 
Term
steroscopic Depth perceotion
Definition
- relies on retinal disparity
-ability of cortical neurons to detect retinal disparity thorugh experience
 
Term
In steroscopic depth perception,what role do the cortical cells do?
Definition
increase responsiveness to axons with syncronized activities
Term

what happens when the eye carries unrelated messages during steroscopic depth perception?

 

 

Definition
cortical cells strengthen connections with only one eye,thus the develoment of depth perception is impaired
Term

what condition causes steroscopic depth perception?

what does it lead to? 

Definition

strabismus- eyes do not point in same directions

leads to LAZY EYE (Amlyopia) 

Term
What is Amlyopia?
Definition
LAZY EYE
- result of strabismus
- child fails to attend to vision in one eye 
Term
How is Amblyopia(lazy eye) treated?
Definition
putting patch over good eye to inhibit competition of input from other eye
Term
What is Astigmatism?
Definition
-blurring of vision for lines in one direction (horizontal or vertical)
- caused by asymmetric curvature of eyes
- in 70% of infants
- can lead to permanent damage in visual cortex 
Term
When is the visual cortex most plastic?
Definition
In early life
Term
What do people with left eye cataracts show?
Definition
mild face recognition problems
Term
light is made of what?
Definition
Photons
Term
What is the process that light goes through in teh retina?
Definition
Ganglion cells
Amacrine cells
Bipolar cells
Horizontal cells
Rod & Cone receptors 
Term
Rods have what inside them? what do they do? during darkness?
Definition
Discs- they have Potassium channels
Darkness- remain open- Glutamate released- depolarization 
Term
what do teh G- proteins do?
Definition
keep Na+ channels open
Term
what does light do to the cells?
Definition
hyperpolarization-less glutamate
Term

Rod is connected to:

works off a: 

Definition
bipolar cell- connected to ganglion cell- works off a gradient potential
Term
What part of the eye has an action potential in it?
Definition
ganglion cell
Term
In terms of ganglion cells, which ones (magno) (parvo) connect to what?
Definition
Rods- magno
Cones- parvo 
Term
what is convergence?
Definition
Many Rods connect to one bipolar cell
Term
What is a one to one correspondence?
Definition
One cone connects to one bipolar cell
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