1. Photon
    a quantum of visible light or other form of electromagnetic radiation demostrating both particle and wave properties
  2. Cornea
    the transparent window into the eyeball
  3. Aqueous humor
    the watery fluid in the anterior chamber of the eye
  4. Crystalline lens
    the lens inside the eye that enables changing focus
  5. Vitreous humor
    the transparent fluid that fills the vitreous chamber in the posterior part of the eye
  6. Retina
    light sensitive membrane in the back of the eye that contains rods and cones, which receive an image from the lens and send it to the brain through the optic nerve
  7. Fundus
    the back layer of the retina-what the eye doctor sees through an ophthalmoscope
  8. Photoreceptors
    light sensitive receptors in the retina
  9. Rods
    photoreceptors specialized for night vision
  10. Coes
    photoreceptors specialized for daylight vision
  11. Synaptic terminal
    the location where axons terminate at the synapse for transmission of information by release of a chemical transmitter
  12. chromophore
    the light catching part of the visual pigments of the retina
  13. the visual pigment found in the rods
  14. Hyperpolerization
    an increase in membrane potential where the inner membrane surface becomes more negative than the outer membrane surface
  15. Graded potential
    an electrical potential that can vary continuously in amplitude
  16. Fovea
    small depression at the center of the macula of the retina
  17. Horizontal cells
    specialized retinal cells that contact both photoreceptors and bipolar cells
  18. Lateral inhibition
    antagonist neural interaction b/w adjacent regions of the retina
  19. Bipolar cells
    retinal cells that synapse with either rods or cones(not both) and with horizontal cells, and then pass the signals on to ganglion cells
  20. Visual Acuity
    a measure of the finest detail that can be resolved by the eyes
  21. Retinal cells that receive visualinfo. from photoreceptors via 2 intermediate neuron types (bipolar cells and amacrine cells) and transmit info to the brain and midbrain
    ganglion cells
  22. P ganglion cells
    receive excitatory input from single midget bipolar cells
  23. M ganglion cells
    resembling little umbrellas that receive excitatory input from diffuse bipolr cells and feed the magnocellular layer of the lateral geniculate nucleus
  24. Receptive field
    the region on the retina in which visual stimuli influence a neuron's firing rate
  25. A cell that depolarizes in response to an increase in light intensity in its receptive field center
    ON-center cell
  26. The difference in luminance between an object and the background, or between lighter and darker parts of the same object
  27. Spatial Frequency
    the number of cycles of a grating per unit of visual angle (usually specified in degrees)
  28. Cycles per degree
    the number of dark and bright bars per degree of visual angle
  29. A function describing how the sensitivity to contrast depends on the spatial frequency (size) of the stimulus
    Contrast sensitivity function (CSF)
  30. Contrast threshold
    the smallest amount of contrast required to detect a pattern
  31. Magnocellular layers
    • the neurons in the bottom 2 layers of the lateral geniculate nucleus
    • physically larger than those in the top 4 layers
  32. The neurons in the top 4 layers of the LGN, which are physically smaller than those in the bottom 2 layers
    parvocellular layers
  33. Primary Visual Cortex (V1)
    the area of the cerebral cortext of the brain that receives direct inputs from the lateral geniculate nucleus

    • responsible for processing visual info.
    • also called striate cortex
  34. Cortical magnification
    the amount of cortical area devoted to a specific region the visual field
  35. Orientation tuning
    the tendancy of neurons in the striate cortex to respond optimally to certain orientations
  36. Column
    a vertical arrangement of neurons
  37. Cytochrome oxidase (CO)
    an enzyme used to reveal the regular array of CO blobs.

    located in the primary visual cortex
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