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Vision Neuro
chapter 6
| Question | Answer |
|---|---|
| sensory transduction | physical stimuli changed to electrochemical signal |
| human vision | 350 to 700 nm |
| cornea | outer protective structure |
| iris | colored opening/ control the pupil |
| pupil | opening in the iris that allows a certain amnt of light |
| sclera | whites/protective layer |
| vitreous humor | gelatinous inside of eye/proteins |
| lens | controls where image is projected onto the retina |
| retina | neural tissue/back of eye/sensory receptors |
| optic nerve | axonal propagations toward the brain |
| retina | photoreceptors/fovea/optic disk |
| rods | low light/ abundant/cylindrical/periphery |
| cones | high acuity/ daytime/ color/toward fovea |
| fovea | focus/most acute/ all cones |
| optic disk | where the optic nerve exits the eye/ blind spot |
| amacrine cells | connect bipolar and ganglion |
| bipolar cells | receptor to ganglion/1 bipolar per photorec |
| horizontal cells | receptors and bipolar/adjust light |
| ganglion cells | axon potentials generated/optic nerve |
| photopigments | opsin/retinal |
| light hits rhodopsin | rod opsin and retinal |
| rod opsin changes color | change in membrane potential |
| visual pathway | retina-optic nerve-optic chiasm-lgn of thalamus-primary visual cortex |
| retino-geniculo-cortical pathway | broken down in thalamus-staysin ipso |
| 6 layers of primate LGN | sep depending on ipsi/contra |
| layers 1 and 2 | magnocellular-larger |
| layers 3-6 | more dorsal/parvocellular |
| layers 1,4,6 | input is contralateral |
| layers 2,3,5 | input ipsilateral |
| center-surround cells | create a field of cells |
| ganglion cells | project 1st ap |
| hartline | frogs/some cells stim more with (out) light |
| on-off cells | only when switch from light to no light and vice versa |
| kuffle | on middle with off periphery(structure) |
| schiller | rod cells= all on cells |
| young's trichromatic | red/green/blue/3 types of receptors |
| trichromatic coding | 3 diff wavelengths |
| blue cone peak | 419 nm |
| rod peak | 496 nm |
| green cone | 531 nm |
| red cone | 559 nm |
| opponent-process coding | blue on, yellow off etc |
| color vision deficits | dichromatics |
| x-linked | protanopia/deuteranopia |
| protanopia | see in yellow and blue/red cones have green opsin |
| deuteranopia | see all 3 colors but green filled w red opsin |
| tritanopia | blue cones absent/defective |
| primary visual cortex | striate cortex |
| pvc | 6 layers w sublayers |
| projections from LGN | enter layer 4 |
| processes info from | ganglion cells and LGN |
| modular organization in V1 | blobs/inter-blobs/ocular dominance |
| blobs | cytochrome oxidase/higher rates of met/color-opp process |
| inter-blobs | orientation of objects/spatial/movement |
| ocular dominance | receive info from same eye/ keep each eye separate |
| vc l 1 | dendrites and axons of other layers |
| vc l 2/3 | projection to temporal and parietal |
| 4 | receive input from LGN |
| 5/6 | project back to LGN |
| hubel and wiesel | V1 line detectors |
| simple | opponent process |
| complex | movement of the line |
| ungerlerder and mishkin | visual association cortex has 2 streams of processing |
| dorsal stream | posterior parietal lobe/magno/where? |
| ventral stream | inferior temporal lobe/m and p/ what? |
| visual association area | analysis/higher order processing |
| magnocellular | no color/high contrast/low spatial/quick |
| parvocellular | color/low contrast/high spatial/slow |
| visual association cortex functions | orientation/mvmt/spatial frequency/retinal disparity/color |
| dorsal stream | location/spatial/terminates in posterior parietal cortex/balint's syndrome |
| optic ataxia | diff reaching for an object |
| ocular apraxia | visual scanning problems |
| simultanagnosia | not more that 1 object at a time |
| ventral stream | highest level of processing/form/3D |
| higher-order processing | V4/ITC/PPC/V5 |
| V4 | color |
| ITC | face cells/complex objects |
| PPC | spatial perception |
| V5 | movement/info from superior colliculus/ |
| achromatopsia | damage to medial occipital lobe/cant remember colors before damage |
| pulvinar | region of thalamus that projects to V5/coordinates eye and hand mvmts |
| fusiform face area | in fusiform gyrus/temporal lobe |
| visual agnosia | deficits in perception w/o blindness |
| apperceptive | cant perceive objects/ |
| prosopagnosia | can't recognize faces |
| associative visual agnosia | cant name objects |