1 Cone Response Visual pathway Decussation Hierarchical and - - PDF document

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1 Cone Response Visual pathway Decussation Hierarchical and - - PDF document

Sensory Systems Modality Stimulus Receptor Class Receptors Vision Light Photoreceptors Rods, cones Nervous Audition Sound Mechanoreceptor Hair cells (cochlea) System Vestibular Gravity, Mechanoreceptors Hair cells (vestibular


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Nervous System Perception Memory Planning ……

Sensory inputs: light, sound, skin pressure,

  • dor …

Motor responses: limb movement, facial expression, speech … Sensory Systems

Dorsal root ganglion neurons Cutaneous mechanoreceptors Muscle and joint receptors Cold and warm receptors Chemical, thermal, and mechanical nociceptors Chemical nociceptor Mechanoreceptor Mechanoreceptor Thermoreceptor Chemoreceptor, themoreceptor, or mechanoreceptor Chemoreceptor Pressure Displacement Thermal Chemical, thermal,

  • r mechanical

Chemical Somatic Touch Proprioception Temperature Pain Itch Olfactory sensory neurons Chemoreceptor Chemical Smell Taste buds Chemoreceptor Chemical Taste Hair cells (vestibular labyrinth) Mechanoreceptors Gravity, acceleration Vestibular Hair cells (cochlea) Mechanoreceptor Sound Audition Rods, cones Photoreceptors Light Vision Receptors Receptor Class Stimulus Modality

Light Projection on Retina

Transduction Transduction

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Cone Response Visual pathway Decussation Hierarchical and Parallel Processing Receptive Field

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Geometry of Projection Geometry of Projection

Retinal image size is inversely proportional to distance

Left eye Right eye

Ponzo’s Illusion

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Muller-Lyer Illusion

“Circular World” of the Zulus (South Africa)

David Marr’s Concept of a Computational Theory for Understanding an Information Processing Task in the Brain

We cannot understand how a bird flies by only studying its wings, but need, in addition, an aerodynamic theory

  • f lift generation by the flow patterns around the wings.

We cannot understand how a computer works by only studying the transistors on the circuit boards and their connections, but need, in addition, concepts of operating system, data structure, and application programs.

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David Marr’s Concept of a Computational Theory for Understanding an Information Processing Task in the Brain

Therefore, even if some day we had complete knowledge of every molecule in the brain, and could record the electrical activities of every cell at any time, we would still not understand how the brain processes

  • information. We need, in addition, a computational

theory which specifies how the electrical signals carried by a large number of neurons could act in concert to solve a certain perceptual problem.