Term
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Definition
| from inside to outside: retian ganglion cells (output) , inner nuclear layer (interneurons), otuer nuclear layer (photoreceptors), and retian pigmented epithelial cells |
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Term
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Definition
| is reversed- so loss of upper vsual field isth e reuslt of loss of hte lwoer retina |
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Term
| you l ook at the retina hrough the pupil |
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Definition
| so the part clsoest ot hepupil l is thei nner part of ther etina part fartehst is the outest part |
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Term
| the three layers betwen celular layers o the retina slide 11 of woodbury |
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Definition
| otuer plexiform between outer nad inntern uclear , inenrplexiform between the innter nuclear and retinal ganglion cels, and the optic fiber layer in fron t of the retinal ganglion cells (the retinal ganglion cells coalesce to form theo pticnerve) |
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Term
| heterogeniety of the retina |
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Definition
| peripheral parts cell layers are alot simperl than central part. The central part has much mreo visua lacuity the nthe peipheral parts. |
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Term
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Definition
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Term
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Definition
| for color, come in different waelengths |
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Term
| compression of ifno needed |
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Definition
| we have waymore hpoto creceptor celsl than retian lganglion cells |
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Term
| mcechanism fo compression |
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Definition
| leaves out stuff inteh mdiel and only transmtis edges. The inner nuclear laey is the one that comrpessedthe image ,takes the informaiton from edges and transmits it to the retinal gnagilon cells, the middle is fileld back in b the isual cortex eventually. |
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Term
| cells fo the inner nucear layer |
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Definition
bipolar cels- involved in vertical transmitsion to retinal ganglion cels.
Horiztonal cells- main emchanism of compression. Do not allow al lthe info from the bipolar cels. If all bipolars cells to ahroizontal cel say they are transmitting light and hte same kidn of light, they will not al lbel et through to the reticualr ganglion. Only if some are trnasmittingd arkness and osme are transmitting light (defining an edge) will mroe bet rnasmitted forwards.
Amycrine cells also exist, appear to be involvedi n compressioans well |
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Term
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Definition
| receptor field compsoed of central area dn surround area. Central area is excitaotry and surrouund are is inhbitiory. When entire field is shown light on , you only get slight uptick in depolarization. An off-center cell has inhbiitory inputs on the inside and exciation on the outsides |
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Term
| center-surround arrangement (sldie 33) woodbury |
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Definition
| arranged in rows so that you get some definition of edges when a bar of lgiht in hsines across |
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Term
| retinal ganglion cel types |
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Definition
M cell- primarily interested in motion, have large axons and large receptive fields so can sendi nformaiton up as fast as possible
P cells- precision vision. smaller axons and receptive fields. Take over second, afetm otion cells. |
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Term
| fovia architecture s lide 38 woodbury |
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Definition
| area of our veyr bets vision. See that the layers therea re pigemnt epithelial cells and lots and lots of photorceptros, all otehr layers are pushesd off to allow light ot pass through. cones only |
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Term
| optic disc slide 39, area of our worst vision |
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Definition
| teh recpetive layers aren ot present. ONly the axosn that are going out are the oens present. NO vision here |
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Term
| lens works backwards, photoreceptors built backwards ,retina works backwards ,photoreceptors signal b ackwards |
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Definition
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Term
| morphology of photoreceptor |
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Definition
| outer segent- where all the pigmetned cells are, inner segmetn- where all the eneryg is generated (mitochidnria etc.), and innermost segment- area of syanptic obdies |
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Term
| photoreceptors function to light level |
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Definition
| when dark, they are very depolarized and erleasing glutamate. Asm ore and more lgiht scoems they hyperpolarie more and more, and release les and les sglutatmate. It is a graded resposen, no AP generation. |
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Term
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Definition
the outersegment rsonds to CGMP-CGMP levels are hgiehsti nt he dark, this causes teh sodium gates to open and depolarizaiton to occur with lots of glutamte release Meanwhile thei nnersemtns potaasisum is constnatly being kickd out without regard to cgmp levels.
When lgith comes cgmp levels f all, sodium stopes entering cell, meancwhiel inner segmetn cells are contiously pumping postassium out, this results in rapid hyperpolarization |
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Term
| Opsin location and function |
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Definition
| This is located in the membraosu discs of the otuer segment. When light hits it , it changes conformation and leadst o G protein signalling cascade |
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Term
| Rhodopsin location adn cuntion |
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Definition
| main photopgiment in rods. Has a kink in teh side chain, light shinign on it striaghtens that kink out. |
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Term
| Rhodopsin location adn cuntion |
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Definition
| main photopgiment in rods. Has a kink in teh side chain, light shinign on it striaghtens that kink out. |
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Term
| Cascade of light response |
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Definition
| starts rhodospin getting activated this goes to the g protein, transducin and causes GDP-GTP exchange, causing activation of transducin. Transducine then actieates PDE, which goes anad cleaves CGMP, inactivating it. |
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Term
| objects in the left hemifield (slide 54 ) wood bury shine on |
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Definition
| the nasal portion of the left eye, and the teporal portion of the right eye. Think of it as objectsi n the left hemifield shine on the righth alf retina |
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Term
| how ifno is sent from eyes to brain (what part in teh brain) |
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Definition
| goes to lateral geniculate nulceus of the thalamus. light coming in from teh left hemifield and in the left eye needst ocross over to get to teh right lateral genicualte nuclus, does so via the optic hciasm. Light from the left hemifield that hits the right eye is already on right sid so goes down to ipsilaterallateral geniculate nuclus |
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Term
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Definition
| blidn in one eye, fine in the other |
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Term
| lesion in teh optic tract |
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Definition
| lsoe vision from an entire hemifield (lose altitle bit of vision i nboth eys |
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Term
| other areas of informaiton transmittance from the eye aside from the lateral geniculate nucleus |
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Definition
| suprachiasmatic(circardian rhythm), pretecum(eye movements), superiro colliuclus (eye movements) |
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Term
| magnoecellular and parvocellular |
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Definition
| areas of the lateral geniculate - magnocellular- inptu form M cells, Parvocellula- input from p cells. magnocellualr deficiency shown in dyslexics (their eyes arent able to st ay o ntrack whe nreading) |
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Term
| inputs in alteral geniculate |
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Definition
| layers -1,4,6 get contraltaeral eye. layers 2,3,5- get isiateral eye |
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Term
| lgn improtant thigns to know |
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Definition
three maps of each retina in each nucleus. retionotopic arrangement (even have receptive fields)
More inputs from the visual cortex than from the eyes.
Magnocellular advantage |
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Term
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Definition
| v1 , in the calcarien sulcus. |
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Term
| lateral geniculate to v1 how? |
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Definition
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Term
| possible courses of the optic radiation to the cortex |
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Definition
| the seurpiro retinal quadrants (lower visual fields) end up on the superior calcarine fissure, the lower retinal fields end up on the inferior retinal quadrants (superior visual fields) (via meyers loop) |
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Term
| damage to tthe otpic chiasm |
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Definition
| anythign that crosses will nto work. So blindness in the left hemifield of the left eye adn the temproal hemifield of the right visual field |
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Term
| damage to the right optic tract |
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Definition
| anythign comign from the left visual field of both the left eye ad the right eye. |
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Term
| damage to the right meyers loop |
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Definition
means that inferior rectal fifeld 8adn therofre superir visual field is lost.
Ths is confined to the left superior quadrant. |
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Term
| lesion at the right striate cortex |
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Definition
| everythign comes together again, so you would expect visual lsot in the left protion of both eyes |
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Term
| retinotopic arrangemetn of calcarine fissure |
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Definition
the poles correpsodn to the fovea(center of yoru eye) whereas the rostral portions correspond to the periphaeral portions of the retina.
More areas of the cortex are dedicated to central regions than peripheral regions. |
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Term
| layers of cortex wel lrepersented in visual fields |
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Definition
| layers 4 and 6 of the cortex resposnible for input and output to the thalamus are highest represetnation |
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Term
| ocular dominance columns . |
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Definition
| we find them in the visual cortex. They replace the lateral genicualte layers taht we saw. Alternating Ipsilater, contralter, ipsilateral , cntoraltere represenations. |
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Term
| comparison of neural numbersi n retina, laGN, and v1 |
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Definition
| 1.0 million retinal ganglion cells , 1.5 illion LGn cells, and 200 million v1 cells. |
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Term
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Definition
have multiple lgn celss synapsing to a single ismple cel. In this way, the simple cell is orientaitno speicfic, will only fire if all of hte geniculate cells arestimulated. They form orietnation columns, in which all celsl wtihin that column respond to aspecific orietnation of light, thsi is superimposed overo culodominance columns.
Just like in occular domiance column, in orientation columns, neighboring cells have sensitivity to different orientations. |
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Term
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Definition
| foudn withi nthe v1, first celsl that are ablet o detect movmeent. HTats becuase they are made up of simple celsl syanpsing to one complx cel. THey are able to detect light in different orietnations, and ahve receptive fieldsbig enough to detect m movement |
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Term
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Definition
| celss that respodns to edges/orientation. Celsl that repsodn to colro and cells that erspodn to motion, yet we cant see. This is because receptive fielsd aof v1 are nto big enough |
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Term
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Definition
| v1 is located jsut aroudn the calrcarine fissure, as go farther and farther ou from calcarine fissure get v2,v3,v4 etc. |
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Term
| function of areas otuside v |
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Definition
| ie. blindspot- we creat vision wherewe can see. |
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Term
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Definition
| we liek symemtry, llight comes rom above |
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Term
| eyes learn form experience nadcreatte things |
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Definition
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Term
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Definition
| color- color bounces of an object and goes to cones a,d then a pattern is done irrespective of how much light is going to the cones. THis is being cells i nv4 have very receptive fiels taht are able to assess full hemifields, and comapres these objectsu nder hte same light to eachother maintaing color constancy. |
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Term
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Definition
| caused yb elsion to v5, unable to see objects once they start moving , motion blindness. |
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Term
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Definition
| vision for action (what do i do with an object) |
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Term
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Definition
| vision for (vision for identification) |
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Term
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Definition
| cuased by bilateral damage to areas in teh temporal lobe. common to have achromotasia, due to damge to v4 as well |
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