COGS 17 Homework 22

  1. Across Fiber Coding
    • When a stimulus is coded through the RATIO of response across multiple cells.
    • i.e. temperature, hot respond more to hot cold to cold, etc.
  2. Convergence (Summation)
    When MULTIPLE pre-synaptic cells all communicate to ONE post-synaptic cell
  3. Divergence
    When ONE pre-synaptic cell communicates to many post-synaptic cells.
  4. Receptive Field
    Set of receptors whose activity influences the activity of target cell.
  5. Excitatory Center-Inhibitory Surround
    Type of Receptive Field: stimulating center increases target response, non-center decreases it.
  6. Topological
    Type of map that preserves spatial relationships (as along a sensory surface).
  7. Magnification Factor
    • In cortex, disproportionate enlargement of the representation of a sensory area of low convergence.
    • (Cortical cells with small Receptive Fields fill a disproportionally large area of the visual projection areas)
  8. Module
    An area of the brain specialized for processing one particular type of information
  9. The Binding Problem
    • The problem posed by having several modules, and yet perceiving wholes.
    • i.e. red square
  10. Retina
    Rear layers of neurons in the eyeball
  11. Visual Receptors (Rods and Cones)
    Cells that respond to light
  12. Rods
    Visual receptor that are (HIGH) convergent, sensitive to motion and low light, mainly in periphery.
  13. Cones
    Visual receptor that connect few to 1 (LOW Convergent), sensitive to color and detail, dispersed plus concentrated in center.
  14. Fovea
    Central area of cone receptors, connected 1:1 for highest acuity.
  15. Bipolar Cells
    (Postsynaptic to Receptors) Next cell in pathway, spontaneous firing, graded potentials, release excitatory NT.
  16. Horizontal Cells
    Inter-neurons that modify reaction of bipolars, implicated in color opponency.
  17. Ganglions
    (Postsynaptic to Bipolars) Next cell in pathway, shows action potentials, release excitatory NT. The axon of this cell forms the Optic Nerve.
  18. Optic Nerve
    Ganglions cell axon form this.
  19. Optic Disc
    Place where optic nerve leaves eye for brain, also called "blind spot"
  20. Amacrines
    • Inter-neurons that modify reaction of optic disc (ganglions), implicated in contrast effects.
    • Graded Potentials, mostly Inhibitory NT, modify interface of Bipolars and Ganglions
  21. Dim
    Level of light that results in greatest release of NT from Receptors
  22. Bright
    Level of light that results in greatest release of NT from Bipolars
  23. Acuity
    High-detail discrimination, as from low convergence, that retains info on differences from rods and cones.
  24. Sensitivity
    High likelihood of detection, as from high convergence that crosses next cell's threshold.
  25. Lateral Inhibition
    • Cell activity resulting in release of inhibitory NT to cells orthogonal to info pathway
    • - Functions mainly to exaggerate differences
  26. Simultaneous Contrast
    Illusion created by lateral inhibition that alters perception of central grey depending on its surrounding.
  27. Uni-directional
    Direction of inhibition in direction-sensitive motion circuit.
  28. Lateral Geniculate Nucleus (LGN)
    Nucleus in Thalamus that processes most visual information from eye.
  29. Column
    In cortex, set of cells, in 6 layers, that all respond to the same preferred stimulus.
  30. Hyper column
    In cortex, set of cells that all have the same Receptive Fields and include set of orientation columns & blobs.
  31. Retinotopic Map
    Topological map that preserves spatial relationships found on retina
  32. V1 (Striate Cortex)
    Primary projection area for vision in occipital lobe of cortex.
  33. Parvocellular Pathway
    Visual pathway specialized for color and detail, that "flows" along bottom of cortex.
  34. Temporal Pathway
    Parvocellular Pathway is also call what because it terminates in the lobe of this cortex.
  35. Who/What Pathway
    Parvocellular Pathway also calls what because it conveys information that helps you to identify a stimulus or individual
  36. X Ganglions
    Small ganglion cells that begin parvocellualr pathways, with small Receptive Fields and sustained response.
  37. Magnocellular Pathway
    Visual pathway specialized for motion and localization, "flows" along top part of cortex.
  38. Parietal Pathway
    Magnocellular Pathway also calls what because it Terminates in this lobe of the cortex
  39. Where/How Pathway
    Parietal Pathway also calls what because it Conveys info that helps locate and interact with stimuli
  40. Y Ganglions
    Large ganglion cells that begin Magnocellular pathway, with large Receptive Fields and transient response.
  41. Superior Colliculus
    Nucleus in Midbrain in Magnocellualar path, processes some visual (esp motion) info from eye
  42. Blindsight
    Though visual cortex damaged and no visual experience, mid-brain enables some visual localization.
  43. Trichromatic Color Vision
    Color coding per ratio of activity of 3 cone types responding to 3 overlapping ranges of frequencies.
  44. Color Opponency
    Recoding of Trichromatic Color Vision, via lateral inhibition from Horizontal cells, into red/green and blue/yellow
  45. Opponent Cells
    LGN or Ganglions with R+G-, G+R-, B+Y-, or Y+B- receptive fields
  46. Color Constancy
    V4 mediated processes that enables identification of color under different light conditions (AKA "retinex theory")
  47. Simple Cells
    Cells in V1 that respond to line, or gradient, oriented in particular direction
  48. Complex Cells
    Cells in V2 that best response to moving lines of particular direction
  49. Spatial Frequencies
    Number of dark/light changes per degree of visual angle
  50. High Frequencies
    Frequency gradients that V1 cells in Parvo path are most sensitive to
  51. Low Frequency
    Frequency gradients that V1 cells in Magno path are most sensitive to
  52. Inferior Temporal (IT)
    End of parvo pathway, includes cells that prefer hand, face, or other complex stimulus.
  53. Prosopagnosia
    Deficit from damage to Fusiform Gyrus, patient cannot recognize familiar faces.
  54. Medial Temporal
    Cortical area with direction-sensitive cells, responds best to stimulus moving across retina.
  55. Medial Superior Temporal
    Cortical area with optic-flow detectors, respond best to contraction/expansion of whole scene.
  56. Superior Temporal Sulcus (STS)
    Area in anterior Temporal lobe that response to Biological Motion
  57. Disparity Detectors
    In V2 or MT, cells that respond to degrees of difference between location of an image on 2 retina
  58. Canonical Cells
    Cells in higher parietal cortex that respond to the affordances of an object
  59. Mirror Cells
    Parietal cells (also found in Premotor Cortex) that respond to seeing self or other perform task.
  60. Tympanic Membrane
    Membrane vibrated by air molecules moving down Auditory Canal
  61. Ossicles
    Three tiny bones (Malleus/Hammer, Incus/Anvil, Stapes/Stirrup) linked into lever system, amplify vibrations of Tympanic Membrane
  62. Oval Window
    Membrane vibrated by the third ossicle bone, initiating vibration of (Endolymph) Cochlear Fluid.
  63. Endolymph
    Thick, incompressible, potassium-rich fluid that fills cochlea.
  64. Cochlea
    snail-like Coiled, three chambered tube [top (Scala Vestibuli), mid (S. Media), bottom (S. Tympani)] in Inner Ear which contains Organ of Corti
  65. Organ of Corti
    Section of central chamber of Cochlea where Receptor Cells are found
  66. Basilar Membrane
    Membrane that runs along floor of Organ of Corti, moves up and down.
  67. Tectorial Membrane
    Membrane that runs along the roof of Organ of Corti, moves forward and back.
  68. Hair Cells
    Auditory receptor cells that are deformed between Basilar and Tectorial Membrane
  69. Cilia
    Tiny "hairs" extending from hair cells whose deformation initiates transduction.
  70. K+ (Potassium)
    Ion that enters receptor, decreasing its polarity (Audition)
  71. Ca++
    Ion that enters the receptor, causing chain reaction that results in release of excitatory NT (Glutamate)
  72. Glutamate
    NT released by auditory receptors
  73. Graded Potential
    Type of change in polarity in auditory receptors
  74. Spiral Ganglions
    Cells to which auditory Receptors communicate, whose axons exit to brain.
  75. Action Potential
    Type of change in polarity in spiral ganglions.
  76. Place Coding
    Relative levels of activity across diffferentially-resonsating basilar membrane code frequency.
  77. Temporal coding
    Rate of oscillation of Bas. Membrane codes frequency per rate of Auditory Nerve Firing
  78. Refractory Period
    Time during which Auditory Nerve Fibers cannot fire next action potential.
  79. Volley Principle
    Since each cell can only fire 1/1000 sec, must work together at alt. intervals.
  80. Phase Locked
    Ganglions involved in Volley Principle can only all fire at the same phase (e.g.) peak of input wave
  81. Intensity Differences
    • Differences used for localization, caused by "head shadow" attenuating high frequencies.
    • Sound at ear closer to source is slightly more intense (louder) than at other ear, because of Head Shadow.
    • -Works best for higher frequencies, since these most likely to be absorbed by head
  82. Phase Differences
    • Differences used for localization, comparing peak and trough of lower frequencies reaching both ears
    • - Peak = oscillating molecules most condensed
    • -Trough = oscillating molecules most rarefied - widely spread out
  83. Timing Differences
    Differences used for localization, per race of left vs. right. Onset signals to superior olive.
  84. Inner Hair Cells
    Receptor cells that show divergent connectivity, for detail freq discrimination.
  85. Outer Hair Cells
    Receptor cells that show convergent connectivity, for loudness discrimination.
  86. Auditory Nerve
    Axons of spiral ganglion in auditory path form this nerve
  87. 8th Cranial Nerve
    Auditory Nerve is part of this cranial nerve
  88. Cochlear Nucleus
    Next synapse in Medulla, beginning of separate information pathways.
  89. Primary Like Cell
    Cells in Cochlear Nucleus that duplicated incoming signal
  90. Tonotopic Map
    Primary Like Cells helps generate what kind of map that represents low>high frequency across cell array
  91. Onset Cell
    Cell in Cochlear Nucleus that transforms incoming signal into a transient burst.
  92. Buildup Cell
    Cell in Cochlear Nucleus that transforms incoming signal into one of graded, increasing amplitude.
  93. Monoaural
    When information from only one ear is involved.
  94. Binaural
    When information from both ears is combined, good for localization as in superior olive.
  95. Superior Olive
    Next auditory site (after cochlea nucleus), also in Medulla, repsonsible for Orienting Reflex
  96. Inferior Colliculus
    Next auditory site (after superior olive), in MIDBRAIN, where info is integrated with visual at nearby site
  97. Medial Geniculate Nucleus (MGN)
    Next auditory site (after inferior colliculus), in Thalamus, site of among other things, A1
  98. A1
    Primary Projection Area for Audition, along Lateral Sulcus of Temporal Cortex
  99. A2
    • Secondary auditory area in cortex
    • Most respond best to complex sounds (familiar noises, speech sounds)
  100. Wernicke's Area
    Area with critical role in comprehension of speech, in left hemisphere
  101. Music
    Type of complex auditory input processed by higher auditory centers in right hemisphere.
  102. Hair Cells
    Type of receptor cells in Vestibular System
  103. K+
    Which Ion, when not/allowed to enter cell, changes receptors polarity
  104. Spontaneous Firing Rate
    Changes in velocity & orientation alter this kind of firing rate.
  105. Otolith Organ
    • Where receptors respond to head tilt via gravity induced deformation by crystals
    • "Ear Stones"
  106. Semi-Circular Canals
    Three fluid filled tubes that detect changes in angular acceleration
  107. Motion Sickness
    Effect when visual and/or motor feedback is inconsistant with vestibular info
  108. 8th Cranial Nerve
    Which Cranial nerve shared with audition
  109. Free Nerve Endings
    • Class of receptors that respond to temperature, pain, itch, and hair follicle movement
    • -respond to change in Temperature (Thermoreceptors) and pain & itch (Nociceptors)
  110. Nociceptors
    Receptors in Free Nerve Endings that respond to "noxious" (potentially damaging) stimuli
  111. Encapsulated Endings
    Class of receptors that respond to touch and internal movement
  112. Proprioception
    Detection of internal movement of muscles and organs
  113. Action Potentials
    Type of response by above type of receptors (encapsulated endings)
  114. Selective Adaptation
    Process by which one type of receptor is fatigues, showing its role in coding
  115. Ventral Posterior Nucleus (VPN)
    Nucleus of Thalamus in somatosensory pathway
  116. Spinal Thalamic Pathway
    Path for pain and temperature info to brain, crossing over in Spinal Cord
  117. Medial Lemniscal Pathway
    Pathway for touch and internal motion info to brain, crossing over in brainstem
  118. Medial Lemniscal
    Pathway tending to be mylinated
  119. Brown-Sequard Syndrome
    • When damage to one side of spine results in different losses on ipsilateral vs contralateral sides
    • -reduction/loss of touch and position sense on the ipsi-lateral (right) side below the point of injury
    • -reduction/loss of temperature and pain detection on the contra-lateral (left) side below the point of injury
  120. Post Central Gyrus
    Location of primary projection area for somatosensory info (S1)
  121. Penfield Map
    Name of topological map of body surface found Post Central Gyrus
  122. Hands/Mouth/ Tongue
    Disproportionally fill Penfield Map.
  123. Substance P
    NT released by pain receptors and other cells in pain pathway
  124. Gate Theory
    Theory concerning top down blocking of pain info entering brain
  125. Periaqueductal Grey Area
    Midbrain Area that is probaby the source of pain info blocking
  126. Endorphins
    "Endogenous morphines" released by Periaqueductal Grey Area
  127. Inhibitory Interneuron
    Type of interneuron in spine that responds to endorphin.
  128. Naloxone
    Opiate antagonist that reduces analgesic effects of morphine and acupuncture
  129. Striate (Skeletal) Muscles
    Type of muscle, made of parallel fibers, attached by tendons to bones.
  130. Flexors
    One type of Striate muscle, that moves bone towards body, in atagonistic pair with extensors
  131. Extensors
    One type of Striate muscle, that moves bone away from body, in atagonistic pair with flexors
  132. Neuro-Muscular Junction
    Where neuron releases NT that depolarizes muscle fiber cells > contraction
  133. Acetylcholine (ACh)
    NT released by effector neurons to contract muscles
  134. Sarcomere
    The contractile unit of a muscle fiber consisting of Myosin
  135. Myosin
    Thick protein filament with knobby bead-like Cross Bridges along it,
  136. Actin
    Thin braided protein filament, anchored to muscle, that myosin hook into and tighten
  137. Spindle
    a proprioceptor that detects passive stretch of a muscle, triggers Stretch Reflexx
  138. Stretch Reflex
    A mono-synaptic reflex that contracts muscle to counter passive stretch
  139. Golgi Reflex
    A reflex triggered by Tendon Organs detecting excessive contraction in muscle
  140. Pain Withdrawal Reflex
    A reflex triggered by pain detectors, rapidly removing skin from the source of pain
  141. Scratch Reflex
    A reflex involving an Oscillator Circuit producing a fixed-rate rhythm
  142. Infant Reflexes
    Reflexes, such as "rooting" or "grasping", found in newborns
  143. Primary Motor Cortex
    Area of cortex that includes body map, sends movement commands to Stem and Cord
  144. Pre Central Gyrus
    Location of the Primary Motor Cortex
  145. Premotor Cortex
    Anterior to the Primary Motor Cortex, active during preparation to move, receives esp from visual-spacial areas
  146. Mirror Cells
    Premotor Cortex includes cells that respond to image of self, or other, performing familiar manual tasks
  147. Brocas Area
    Lateral area that plans articulation, helps generate gramatical sentences (esp. in left hemisphere)
  148. Supplementary Motor Cortex
    Dorsal to Broca's Area, also active during prep, esp. for rapid movements, receives from Parietal
  149. Corticospinal Pathways
    Fast, crossing paths from Pyramids in cortex, esp. for precise control of peripheral moves
  150. Red Nucleus (Tegmentum)
    Cortico-Spinal Pathway stops at this Midbrain structure on the way from the Cortex to Medulla and Cord
  151. Ventro-medial pathway
    Mainly ipsilateral pathways for posture & gross movement of neck, shoulders & trunk
  152. Cerebellum
    "Little brain" involved esp in coordinated movement requiring aiming and timing
  153. Ballistic
    Movements that occur very rapidly and generally cannot be altered once begun
  154. Purkinje Cells
    "Telephone poles" in cerebellar cortex that help code time as distance
  155. Parallel Fibers
    "Wires" in Purkinje Cells whose action potentials release excitatory NT
  156. Deep Nuclei
    Central areas that receive from Purkinje Cells ("Telephone Poles") and send output to brain/chord
  157. Basal Ganglia
    Set of forebrain structures controlling posture, muscle tone, and smooth movement
  158. Parkinson's Disease
    Movement impairment, marked by rigidity, tremors, etc, for degeneration of Substantia Nigra
  159. Substantia Nigra
    Midbrain structure whose dopaminergic axons synapse in Basal Ganglia
  160. L-DOPA
    Precursor of dopamine, crosses blood-brain barrier, converted by neurons into dopamine
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COGS 17 Homework 22