17Su11Lec4.2

17Su11Lec4.2 - CS17 Neurobiology of Cognition Summer 2011 Lecture 4.2 Vision Continued Information Pathways NOTE While paths have stops in

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CS17 Neurobiology of Cognition Summer 2011 Lecture 4.2 Vision - Continued Information Pathways NOTE : While paths have stops in common (e.g. LGN, V1, V2) information sub-pathways remain largely independent Parvocellular Pathway (“Ventral Stream ”, “Temporal Pathway”, “ What/Who Pathway”) For identifying stimuli - Specialized for (shape, texture); Integrated with Language centers for naming identified objects - Begins at Cones in and near Fovea => Mostly Parvocellular (small) Ganglions (called “X Ganglions”), w/small RFs , give sustained response => Basic pathway (with sub-paths): Top 4 layers of LGN ( Lateral Geniculate Nucleus ) of Thalamus => V1 (“ Striate Cortex ”) => V2 => V3 => V4 all in Occipital lobe => IT (in Inferior Temporal Cortex) Magnocellular Pathway (“Dorsal Stream ”, “Parietal Pathway”, “ Where/How Pathway”) For visio-spatial mapping - For detecting environment including gross outline Integrated w/ Somatosensory info from antero-dorsal Parietal and with Premotor & Motor Cortex from Frontal => Mostly Magnocellular (large) Ganglions (called “Y Ganglions”), large RFs , transien t response => Some of these to Superior Colliculus of Midbrain (e.g. for “Blindsight ”), then on to LGN => Most Y Ganglions go directly to (bottom 2 layers of) LGN; All=> V1 => V2 => MT (Medial Temporal Cortex) => MST (Medial Superior Temporal Cortex) => <= Posterior Parietal Cortex The WHAT/WHO (Ventral Stream / Parvocellular) Pathway COLOR : Spectra of “visible light” include wavelengths (or s ) ranging from ~350nm to ~700nm - e.g. Prism refracts different s = rainbow: ROYGBV (red, orange, yellow, green, blue, violet) - Short s seen as violet & blue, Med s as green, Med-long s as yellow, Long s as orange & red Trichromatic Color Vision – Young-Helmholtz Theory - 3 Cone types (Short, Medium, Long); Each w/diff type of Opsin that determine which
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This note was uploaded on 09/07/2011 for the course COGS 17 taught by Professor Pineda during the Spring '06 term at UCSD.

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17Su11Lec4.2 - CS17 Neurobiology of Cognition Summer 2011 Lecture 4.2 Vision Continued Information Pathways NOTE While paths have stops in

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