Term
| What does it mean to transduce energy? |
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Definition
| The receptors transduce or convert energy (light) into electrochemical patterns |
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Term
| What is receptor potential? |
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Definition
| Local depolarization or hyperpolarization of membrane |
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Term
| What determines the hyperpolarization of inhibition of the next neuron in a receptor potential? |
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Definition
| The strength of the receptor potential |
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Term
| what is the law of specific nerve energies? |
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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 |
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Term
Amacrine cells
what are they?
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Definition
| Amacrine cells control ability of ganglion cells to respond to shapes and movements |
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Term
| What are the parts of the Retina and where os the Retina located? |
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Definition
- REtina is located at the baCK of the eye
- Comprised of
Macula - center of human retina
Fovea- |
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Term
| What is the FOVEA and Where is it located |
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Definition
Located in center of Macula
Allows for detailed acute vision
High density of receptors
Nearly free of blood vessels and ganglion axons |
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Term
| What part of the eye is nearly free of blood vessels and ganglion axons |
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Definition
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Term
| The Receptors in the Fovea are connected to what? |
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Definition
| Single bipolar cell and ganglion cell (midget ganglion) |
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Term
| What are midget ganglion cells? |
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Definition
| in the fovea of humans, called midgests because each is small and responds to just one single cone, has direct line to brain |
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Term
Receptors outside fovea do what?
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Definition
-increased number of of receptors converge on bipolar and bipolar cells -decreased acuity -Increase vision under low light conditions |
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Term
| what are two kids of Verterbrate photoreceptors |
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Definition
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Term
| Name the Specs of the Rods |
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Definition
-Abundant in periphery - respond to faint light - 120 million per retina |
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Term
| Name the specs of the cones |
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Definition
-Abundant in Fovea -For color vision -High acuity - 6 million per retina |
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Term
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Definition
-Contained by both rods and cones -chemicals that release energy when struck by light - have 11 cis-retinal bound to protiens called opsins |
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Term
| When is the 11 cis retinal stable? |
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Definition
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Term
| What does light energy convert 11 cis retinal to? |
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Definition
| All-trans retinal- light is absorbed energy is released |
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Term
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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
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Term
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Definition
percieve color in terms of paired opposites - bipolar cells may be xcited by one wavelength and inhibited by another |
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Term
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Definition
cortex compares info from various parts of the retina to determine color for each area ex rubix cube takes away comparisons |
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Term
| Color Deficiency- what is is? |
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Definition
Impairment in percieving color differences - caused by abnormal cones - most common between red and green cones |
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Term
| What chromosome carries the color deficieny gene? |
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Definition
Carried on the x chromosome
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Term
| what are Magnocellular Ganglionic Neurons |
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Definition
Input from rods responsive to movement big cell bodies |
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Term
| what are Parvocellular ganglionic neurons |
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Definition
small cell bodies color detail and still or slow object input from cones |
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Term
| Koniocellular gnaglionic neurons |
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Definition
small cell bodies found throughout retina |
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Term
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Definition
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Term
| Lateral Geniculate Nucleus |
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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 |
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Term
| what is the primary visual cortex? V1? |
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Definition
Recieves info from lateral geniculate nucleus -1st stage of visual processing |
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Term
| Name the cells of the visual cortex |
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Definition
simple cells- found primarily fixed excitatory and inhibitory zones - bar shapes and edge shaped receptive fields outnumber diagonal |
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Term
Compex cells where are they located? |
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Definition
-found in v1 or v2 -large receptive field lackingfixed excitatory and inhibitory zones |
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Term
| what do complex cells respond to? |
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Definition
| prefer stimulus moving perpendicular to axis |
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Term
| what are hypercomplex cells? |
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Definition
similar to complex cells but with strong inhibitory fields at the end of visual field |
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Term
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Definition
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Term
| Cells of visual cortex process what? |
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Definition
simliar information such as oreintation and source - may have feature detectors- neurons whose response indicate prescence of particular feature or stimuli |
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Term
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Definition
ability to recognize object's shape despite changes in direction or size |
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Term
| What can damage in pattern pathways in cortex lead to? |
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Definition
deficits in object recognition
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Term
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Definition
inablity to recognize faces - due to damage to pattern pathway in temporal cortex |
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Term
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Definition
inablity to recognize faces due to damage in the fusiform gyrus of inferior temporal cortex |
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Term
| What does the Middle temporal cortex or v5 respond to? |
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Definition
stimulus moving in particular direction
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Term
| what do cells in the Medial Superior Temporal (MST) cortex respond to? |
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Definition
exapnsion and contraction or rotation of visual stimulus ex. star wars effect- stars going past |
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Term
| What areas recieve direct input from the magnocellular path? |
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Definition
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Term
| What does the magnocellular path of the MT MST detect? |
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Definition
overal patterns including movement over large areas of the visual the visual field
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Term
| What do parvocellular paths of the MT MST detect? |
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Definition
disparity between views of teh left and right eyes, important for distance
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Term
| What does the Fusifor face area do? |
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Definition
specialized for faces- brittany spears neurons |
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Term
| how many days after birth does a newborn recognize faces? |
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Definition
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Term
| what does lack of early stimulation do? in ONE eye? in Both eyes? |
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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 |
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Term
| what are the sensitive/ critical periods? |
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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 |
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Term
| steroscopic Depth perceotion |
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Definition
- relies on retinal disparity -ability of cortical neurons to detect retinal disparity thorugh experience |
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Term
| In steroscopic depth perception,what role do the cortical cells do? |
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Definition
increase responsiveness to axons with syncronized activities
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Term
what happens when the eye carries unrelated messages during steroscopic depth perception? |
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Definition
cortical cells strengthen connections with only one eye,thus the develoment of depth perception is impaired
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Term
what condition causes steroscopic depth perception? what does it lead to? |
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Definition
strabismus- eyes do not point in same directions leads to LAZY EYE (Amlyopia) |
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Term
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Definition
LAZY EYE - result of strabismus - child fails to attend to vision in one eye |
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Term
| How is Amblyopia(lazy eye) treated? |
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Definition
putting patch over good eye to inhibit competition of input from other eye |
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Term
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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 |
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Term
| When is the visual cortex most plastic? |
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Definition
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Term
| What do people with left eye cataracts show? |
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Definition
mild face recognition problems
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Term
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Definition
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Term
| What is the process that light goes through in teh retina? |
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Definition
Ganglion cells Amacrine cells Bipolar cells Horizontal cells Rod & Cone receptors |
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Term
| Rods have what inside them? what do they do? during darkness? |
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Definition
Discs- they have Potassium channels Darkness- remain open- Glutamate released- depolarization |
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Term
| what do teh G- proteins do? |
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Definition
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Term
| what does light do to the cells? |
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Definition
hyperpolarization-less glutamate
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Term
Rod is connected to: works off a: |
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Definition
bipolar cell- connected to ganglion cell- works off a gradient potential
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Term
| What part of the eye has an action potential in it? |
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Definition
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Term
| In terms of ganglion cells, which ones (magno) (parvo) connect to what? |
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Definition
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Term
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Definition
Many Rods connect to one bipolar cell
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Term
| What is a one to one correspondence? |
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Definition
One cone connects to one bipolar cell
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