1 / 27

Introducing Perception

Introducing Perception. Of microbes and men. O rganisms from microbes to man must interact with the world F ind food and mates, avoid predators and physical harm. Representing the world.

karlyn
Télécharger la présentation

Introducing Perception

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Introducing Perception PSY 295 - Fall 2012 - Grinnell College

  2. Of microbes and men • Organisms from microbes to man must interact with the world • Find food and mates, avoid predators and physical harm PSY 295 - Fall 2012 - Grinnell College

  3. Representing the world • Organisms extract information about the environment tobuild an internal representation of the environment • Representations guide their actions from Russel & Norvig (1995) PSY 295 - Fall 2012 - Grinnell College

  4. Sources of useful information • Reflected light • Pressure/temperature • Sound waves • Chemical gradients PSY 295 - Fall 2012 - Grinnell College

  5. Representations • Sensory representations need not be sophisticated to be useful • Even single cell organisms respond to sensory cues PSY 295 - Fall 2012 - Grinnell College

  6. Euglena • Single cell photo-synthetic organism • Has eyespot which is sensitive to light • Moves towards light – Phototaxis PSY 295 - Fall 2012 - Grinnell College

  7. Bacteria • Swim towards food and away from poisons • Chemotaxis PSY 295 - Fall 2012 - Grinnell College

  8. Nervous systems • Sensation and action in single-cell organisms are mediated by biochemical pathways • In multicellular organisms, sensation and action are mediated by the nervous system PSY 295 - Fall 2012 - Grinnell College

  9. The neuron • Nervous systems are comprised of neurons • Neurons are cells specialized for transmitting information PSY 295 - Fall 2012 - Grinnell College

  10. Neural networks • To perform complicated information-processing, neurons are arranged into neural networks PSY 295 - Fall 2012 - Grinnell College

  11. Sensation and Action • World-representing only useful if the organism can move • Organisms that cannot move do not need nervous systems PSY 295 - Fall 2012 - Grinnell College

  12. Tunicates • Larval form is like a tadpole which swims around • Once it finds a suitable rock, it cements itself in place and proceeds to digest its own brain PSY 295 - Fall 2012 - Grinnell College

  13. Sensory-motor transformations • A simple example of sensation leading to action is a reflex PSY 295 - Fall 2012 - Grinnell College

  14. Interneurons • More sophisticated sensory-motor transformations require an intervening hidden layer of interneurons PSY 295 - Fall 2012 - Grinnell College

  15. Bending reflex in leech from Churchland & Sejnowski 1992 PSY 295 - Fall 2012 - Grinnell College

  16. Leech reflex circuit from Churchland & Sejnowski 1992 PSY 295 - Fall 2012 - Grinnell College

  17. Far Side Cartoon “Stimulus, response, stimulus, response. Don’t you ever think?” PSY 295 - Fall 2012 - Grinnell College

  18. More sophisticated representation • Building more accurate representations of the world like we do can provide great advantages • Remember, reason about, and simulate the world PSY 295 - Fall 2012 - Grinnell College

  19. Sources of useful information • Reflected light • Pressure/temperature • Sound waves • Chemical gradients PSY 295 - Fall 2012 - Grinnell College

  20. Light • Provides information about things far away from the organism • Organisms living in caves or in deep sea often lack eyes Texas blind salamander PSY 295 - Fall 2012 - Grinnell College

  21. Evolution of eyes • Eyespots are simplest ‘eyes’ • Cup eyes give directionality from Land & Ferdnald 1992 PSY 295 - Fall 2012 - Grinnell College

  22. Evolution of eyes • Pinhole opening helps to focus light • Reduces amount of light entering eye from Land & Ferdnald 1992 from Palmer 1999 PSY 295 - Fall 2012 - Grinnell College

  23. Evolution of eyes • A lens focuses the image while permitting lots of light into eye from Palmer 1999 from Land & Ferdnald 1992 PSY 295 - Fall 2012 - Grinnell College

  24. Visual system • A sophisticated eye and visual system permits detailed analysis and interpretation of the scene from Hubel (1995) PSY 295 - Fall 2012 - Grinnell College

  25. This course • We will study information processing and perception in mammalian sensory systems • Touch, vision, hearing, olfaction, taste • Strong emphasis on sensory neuroscience • Connections to machine vision, medicine and consciousness PSY 295 - Fall 2012 - Grinnell College

  26. Related courses • Fall 2012 • Machine Vision (CS-295-02) • Vision Science Seminar (NRS-495) • Physiological Psychology (PSY-246) • Spring 2013 • Computational Neuroscience (PSY-395) PSY 295 - Fall 2012 - Grinnell College

  27. See you later! PSY 295 - Fall 2012 - Grinnell College

More Related