psych test 2

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psych test 2
2010-03-25 00:15:50
ear eye and movements

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  1. law of specific energies (muller)
    whatever excites a particular nerve establishes a special kind of energy unique to that nerve. in other words, the neurons action potential always conveys the same kind of info
  2. trichromatic theory (young helmholtz)
    we perceive color by comparing the responses of three types of cones. long and medium wavelength cones are more abundant than short so its yeaseir to see yellow, red or green than blue.
  3. opponent process theory
    brain sees color on a continuum from red to green adn another from yellow to blue. we perceive color in termed of paired opposites. explains why we cant see redissh green or bluish yellow. explains negative color after images
  4. retinex theory
    color perception requires some reasoning, not simply stimulation. the cortex compares info from various areas in teh retinea to determine the brightness and color perception for each area.
  5. color constancy
    the ability to recognize the color of an object, even if the lighting changes. accomplished by comparing the color of one object with the color of another
  6. receptive field
    the part of the visual field to which only one neuron responds; for a given receptor, the point in space from which incoming light strikes the receptor
  7. lateral inhibition
    the reduction of activity in one nearuon by activityu in neighboring neurons. the reintas way of sharpening contrasts to emphasize the border between one object and the next
  8. parvocellular
    small ganglion cell bodies and small receptive field, located near fovea. detect visual detail and color. all axons go to lateral geniculate nucleus
  9. magnocellular
    larger ganglion cell bodies and receptive fields, distributed fairly evenly thorught retina. respond to moving stimuli and pattersn. not color sensitive or detial sensitive. most axons go to lgn but some go to other visual areas of the thalamus.
  10. koniocellular
    small ganglion cell bodies that occur throughout the retina. axons go to lgn, thalamus and superior colliculus
  11. which path is most sensitive to movement?
    magnocellular path. from ventral branch to temporal cortex
  12. which path integrates vision with action?
    magnocellular path from the dorsal branch to teh parietal cortex
  13. which path is most sensitive to details of shape?
    parvocellular path to temporal cortex
  14. which path is sensitive to brightness and oclor but also sensitive to shape?
    mixed parvo/magnocellular path to temporal cortex
  15. ventral stream
    visual paths in temporal cortex. the what pathway specialized for identifying and recognizing objects. if damaged, we can find and pick up objects but cannot describe them
  16. dorsal stream
    visual path in parietal cortex. the where adn how path. helps motor system find objects move ward them and pick them up. if damaged, we can describe object but cant find and pick them up
  17. simple cells
    fixed small receptive field, found in primary visual cortex. have fixed excitatory and inhibitory zones and most have bar or edge shaped receptive fields, which may be horizontal vertical or intermediate
  18. complex cells
    large receptive field. located in area v1 or v2; cannot be mapped into excitartroy or inhibitory zones. respond to a light in a particular orientation anywhere within large receptive field. receive input from combo of simple cells
  19. feature detectors
    neurons whos reponses indicate the presence of a particular visual feature (square or round) waterfall effect
  20. visual agnosia
    inablility to recognize some objects. can describe but dont kno what they are
  21. prospagnosia
    inability to recognize faces, identify individuals. can still read and recognize person by their voice. inferior temporal cortex area (fusiform gyrus) especially active in recognition of faces
  22. what does color perception depend on?
    both parovecullular and konicellular pathways
  23. what pathway does brightness mostly depend on?
    magnocellular pathway
  24. sterioscopic depth perception
    the ability to perceive depth based on the discrepancies between the visual input from each eye. accomplished through the magnocellular pathway
  25. which two temporal regions are responsible for motion detection?
    middle temporal and medial superior temporal
  26. what do cells in the MT area respond to?
    stimulus moving in a particular direction
  27. what do cells on MST respond best to?
    expansion, contraction, or rotation of large visual scene (moving borders within their receptive fields, when an object moves a certain direction relative to its background) allows us to distinguish btwn the result of eye movements and result of moving objects
  28. what is visual attention dependent on?
    amount and duration of activity in the cortical area
  29. blindsight
    loss of visual field but person can still point out objects or light in the blind field. some healthy tissue remains to provide this
  30. how does visual cortex bind color, shape and movement to an object and bring it to conscoiusness?
    consciousness is distributed over several cortical areas is the most dominant hypothesis
  31. outer ear or pinna
    cartilage attached to the side of the head that laters reflecitons of sound waves and therefore helps us locate sounds
  32. middle ear
    the typanic membrane or eardrum vibrates at the same frequency as incoming sounds waves
  33. what are the middle ear bones?
    hammer, anvil and stirrup
  34. inner ear or cochlea
    snail shaped structure of the inner ear that contains three fluid filled tunnels
  35. where do hair cells lie between?
    the basilar membrane and the tectorial membrane of teh cochlea
  36. frequency theory
    basilar membrane vibrates at the same frequency of sound, causing auditory neurons to produce action potentials at the same frequency. but neaurons cant fire abouve 1000 hz becuase of refractory period, so something else must be happening
  37. place theory
    each area of basilar membrane vibrates to a different frequency..but basilar membrane is bound together and no part can vibrate separatley
  38. current theory
    at low frequencies, the frequency of impulses identifies the pitch, and the number of firing cells identifies the loudness. up to 100 hz, basilar membrane vibrates in synchrony and audiory neurons produce one active potential per wave. at higher frequencies neurons fire only to some of the wayves but are phase locked to peaks of cells (ex - neuron fires on every 2nd 3rd or 4th wave)
  39. volley principle
    the auditory nerve as a whole can have colleys of impulses u;p to 4000 hz per second even though no individual nearoun can fire that quickly. most hearing about 4000 jhhz not important in human speech or muisc, bnut when we hear sounds in higher frequencies, a mechanism similar to place theory takes over
  40. auditory pathway
    output of inner ear goes to several subcortical structures. corssover occurs at midbrain so that each ehmipehr of forebrain gets major input from opposite ear
  41. primaryt auditory cortex (superior temporal lobe)
    a cell respnds best to ne tone and cells preferring a given tone cluster together. damange impairs ability to reconzie complex/sequential sound such as music or convo; simple sounds not affected. the cortex is not essential for all hearing but for advanced processing of sound
  42. vestibular organ
    monitors movement of head, directs eye compensation andmaintains balance. adjacent to cochlea. consists of saccule, utricle, and thee semicircular canals
  43. pacinian corpuscles
    detect sudden displacements or high frequency vibrations on the skin (onion like structure)
  44. meissners corpuscles
    hairless area only which detects sudden displacement and low frequency vibrations on skin
  45. free nerve endings
    detect pain, warmth and cold
  46. ruffini endings
    detect stretch of skin
  47. merkels disks
    detect indentation of skin
  48. somatosenstaion
    sensation of the body and its movemenets
  49. what aliviates pain?
    opioid mechanisms. these are the systems that respond to opiates and similar chemcial compounds like narcotics, morphine etc. toperate by blicking the relaease of subtance p
  50. endorphins
    bind to opiate receptors and are stimulated by pain, sex, long distance running ,a dn thrilling music
  51. gate control theory (melzack and walls)
    spinal cord receives messages formpain recpetors but also other skin recpetors and axons descending from the brain. these other inputs sometimes close the gate for the pain messages. the gate is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by info coming back from the brain
  52. myasthenia gravis
    auto immune disease. immune system anti bodies attack acetocholine receptors. wakness and rapid fatigue of muscles because motor neurons cant constantly produce maximum acetylcholine necessary to move muscles normally. reated by drugs that inhibit acetylcholinesterase
  53. proprioceptors
    receptor that is sensitive to the position or movement of a part of the bbody. it detects the strech and tension of a muslce and sends mesages to the spinal cord to adjust