Neurophys 8 Flash Cards

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Title: Neurophys 8
Description: Neurophys 8
Number of Cards: 37
Save Count: 0
Author: dethlovemag9
Created: 2012-01-21
Tags: 8 neurophys
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    • Question
    • Answer
    • Side 3
    • Light coming from the right visual field hits the left
      eye at the
    • temporal hemiretina and the
      nasal hemiretina on the right eye
    • fibers from the temporal hemiretina stays on the
      same size once they get to the optic chiasma, while the nasal hemiretina fibers
    • crosses to the opposite side and then mix with the
      temporal ones
    • once past the optic chiasma, the optic nerve becomes
    • the optic tract
    • Lateral geniculate nucleus
      Layers 1,4,6 from
      2,3,5
    • contralateral
      ipsilateral eye
      and segregation of On and Off pathways
    • what type of cells on layers 5 and 6
      what type of cells on layers 3,4
      1,2
    • on cells
      off cells
      both
    • The fibers coming from the optic tract eventually
      get to the lateral geniculate nucleus (geniculate
      means bender knee) there are just as many fibers
      coming back from cerebral cortex to LNG as the ones that
    • ones that leave from LNG to the cerebral cortex
    • parvocellular means
    • small cells in layers 3-6
    • magnocellular means
    • big cells 1,2.
    • Magnocellular cells are
    • not
      wavelength-selective; large
      receptive field; phasic
    • Parvocellular cells are
    • wavelength sensitive, small
      receptive field; tonic
    • LGN characteristics
    • Retinotopic map in LGN
      Center-surround
      organization of cells
    • what cells synapse from retina to parvocells in the LGN?
    • Midget cells
    • what cells synapse from retina to magnocells in the LGN
    • paracells
    • LNG fibers make synapse at broadmanns area
    • 17
      or area v one on the primary visual cort
    • The left side
      of the visual info ends up in the right portion of
    • the brain
    • One thing we notice about the representation
      of the fovea in the Lgn is the phenomenon known as
    • cortical ,magnification
    • In the visual cortex,
      cells have different responses than the cells in the
      Lgn, no longer we have center surround fields, rather they prefer
    • bars of light in a specific orientation
    • simple cells
    • shaped central area, with + in it so a bar of light
      causes a burst of ap..and it has a surround, if
      illuminated the signal decreases if both the
      surround and the central bar shaped area get
      stimulated the eye doesn't respond
    • LGN retinotopic map in the visual cortex is
    • retained
    • Simple cells
      Can respond to bars of
    • darkness or bars of light
    • Current hypothesis for how
      receptive fields of simple
      cells are established
    • adding
      up inputs from centersurround
      receptive fields of
      LGN cells
    • complex cells derived their response from
    • the summation of simple cells
    • As we take an
      electrode and we put it in a column
    • all the cells in that column will respond to the same stimuli
    • Orientation selective cells
    • as you march down
      through the cortex, cells tend to like the same
      orientation
    • Input into visual cortex from the Lgn is still
      segregated by
    • eye and we get a pattern with a
      bunch of fibers say from the right eye nearby
      there's a bunch of connection of the left eye. Ocular
      dominance columns demonstrate through aa
      labeling that there's still segregation of the right
      and left eye. On the cortex the bending pattern
      represents the stimulation of only one eye either
      right or left. But in a newborn this fibers are
      intermixed early in development and with time the
      inputs are segregated
    • Cells in layer 4c monocular;
      elsewhere, can see
    • binocularly
      driven cells (for the first time)
    • Amblyopia
    • disease of visual cortex
      (ex: lazy eye, monocular cataract)
    • Critical period
    • time when synaptic
      contacts can be easily modified
      Patch to force other eye to work
    • On area v1 of cortex finally we can see
    • cells driven
      by two eyes
    • At the junction of occular dominant
      columns are the cells that
    • respond to both eyes
      stimuli.
    • Amblyopia is a
    • disease of the visual cortex
    • a monocular cataract causes amblyopia because
    • In a monocular cataract causes amblyopia because
      pattern vision is lost meaning the input to the
      vision cortex will be highly dimished while the
      other eye in takes over the function of the other
      eye..so this means that there is a windown of
      opportunity for fibers of one to take over the other
      during development before we get to teenage yrs. If
      the cataract is removed retina and Lgn respond
      well but not the cortex cells. Young individual
      treated for lazy eye wear a patch over the good eye
      so that you dont use it so the other eye can
      compete to make its own connections
    • Binocularly driven cells in
      areas beyond
    • layer 4
    • Summary of inputs and
      response properties in
      cortex
    • Orientation-selectivity
      Ocular dominance columns
      Binocularly driven cells in
      areas beyond layer 4
      Color blobs
      Still separation of M and
      P pathways
    • Color blobs
      in the middle of the column are responsive
    • to selective color
    • Info from v1 splits into dorsal and
      ventral pathways. Ventral involved in
      dorsal
    • object recognition
      spatial vision
    • Motion info goes to area
    • MT; color to a different area, V4