F07Homework2Answers

F07Homework2Answers - CS17 * F07 Name_ HOMEWORK 2...

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CS17 * F07 HOMEWORK 2 Name______________________________ PERCEPTUAL SYSTEMS Across Fiber Coding When a stimulus is coded through the RATIO of response across multiple cells Convergence (or Summation) When multiple pre-synaptic cells all communicate to one post-synaptic cell Divergence When one presynaptic cell communicates to many post-synaptic cells Receptive Field Set of receptors whose actitvity influences the activity of target cell Excitatory Center- Inhibitory Surro Type of above: stimulating center increases target response, non-center decreases it Topological Type of map that preserves spatial relaitonships (as along a sensory surface) Magnification In cortex, disproportionate enlargement of the rep. of a sensory area of low convergence Module An area of the brain specialized for processing one particular type of information The Binding Problem The problem posed by having several of the above, and yet perceiving wholes VISION Retina Rear layers of neurons in the eyeball Cells that respond to light; show spontaneous, graded release of inhibitory NT Rods Cones Fovea Central area of above receptors only, connected 1:1 for highest acuity Bipolars Next cell in pathway, spontaneous, graded potentials, release excitatory NT Horizontals Inter-neurons that modify reaction of above, implicated in color opponency Ganglions Next cell in pathway, action potentials, release excitatory NT Optic Nerve Formed of axons of the above Optic Disc Place where above leaves eye for brain, also called "Blind Spot" Amacrines Inter-neurons that modify reaction of above, implicated in contrast effects Dark Current Flow of Na* in/out of receptor, in absence of light > spontaneous release of NT Ca++ Ion that enters receptor, causing chain reaction that results in release of NT Dim Level of light (bright or dim?) that results in greatest release of NT from receptors Bright Level of light (bright or dim?) that results in greatest release of NT from bipolars Acuity High-detail discrimination, as from low convergence, that retains info on diffs Sensitivity High likelihood of detection, as from high convergence that crosses next cell's threshold Lateral Inhibition Cell activity resulting in release of inhibitory NT to cells orthogonal to info pathway Simultaneous Contrast Illusion created by above that alters perception of central grey depending on its surround Uni-directional Direction of inhibition (uni- or bi-directional?) in direction-senstive motion circuit Lateral Geniculate Nuc or LGN Nucleus in Thalamus that processes most visual information from eye Column In cortex, set of cells, in 6 layers, that all respond to the same preferred stimulus Hyper-Column Retinotopic Map Topological map that preserves spatial relationships found on Retina
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F07Homework2Answers - CS17 * F07 Name_ HOMEWORK 2...

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