Sensation and Perception

1
Sensation and Perception

• Sensation Biological conversion of energy into a
  pattern of response
• Perception Mental interpretation

2
Vision

• Neurons fire in response to visible light
  (400-700 nanometers)
• Light does not have color merely how we
  interpret wavelength information
• Subtractive process (paint)
• Additive process (light)

3
Structure of the Eye

• Cornea
• Iris
• Pupil
• Lens
• Retina (blind spot)
• Visual Receptors
• Rods vision in dim light (periphery)
• Cones color and detailed vision (center)

4
Color Vision

• Trichromatic Theory three types of cones. Color
  vision depends upon the relative rate of response
  of these three types of cones (like primary
  colors)
• Opponent-Process Theory see in terms of a system
  of paired opposites (red/green yellow/blue
  black/white). Bipolar cells found in thalamus

5
Hearing

• Conversion of sound waves into mechanical
  displacements of a membrane that a row of
  receptor cells can detect.
• Structure
• Pinna (outer ear)
• Hammer (malleus), Anvil (Incus), Stirrup (Stapes)
• Cochlea (contains basilar membrane and hair
  cells)
• Semicircular Canals

6
Localization of Sound

• Visual Cues
• Compare information going into two ears

7
Vestibular Sense

• Tells us the position of our head relative to
  gravity.
• Posture
• Balance
• Adjusting eyes in relation to head movements
• Sensory receptor cells are hair cells in the
  semicircular canals (inner ear).
• Ear infections and balance

8
Cutaneous Senses Touch

• Number of different senses and receptors
• Pain What function does pain serve?
• Combination of physical and mental processes
• Biological mechanisms
• Substance P and Endorphins
• Capsacain and hot peppers

9
Gate Theory of Pain

• Activity of the brain can facilitate or inhibit
  the transmission of pain messages.
• Sports competition
• Survival
• Distraction (e.g., nice view from hospital window)

10
Chemical Senses Taste and Smell

• Taste traditional map of tastebud distribution
  on tongue is incorrect
• Chemicals must be in solution
• Sweet, sour, salty, bitter
• Spicy?
• Linked very closely to smell (olfactory sense)

11
Olfactory Sense Smell

• Receptors located on mucous membrane in the rear
  air passage of nose
• Specific receptor cell for each specific smell
  (10,000 different odors)
• Close link to memory (amygdala and limbic system
  first process information)
• Pheromones

12
Perception Vision

• Recognition of patterns
• Feature detector approach belief that we have
  specific cells in our brain that recognize very
  specific shapes and patterns
• Gestalt approach belief that we have the ability
  to pick out configurations and overall patterns
• Proximity, similarity, closure
• Of course, the answer is that we use both

13
Depth Perception

• Retinal disparity compare the views of an image
  on the two retinas.
• Discrepancy becomes larger as the object comes
  closer
• Convergence of the eyes the closer an object,
  the more the eyes turn in
• These two processes involve binocular cues
• Monocular Cues object size, texture, shadows,
  interposition (overlap of objects), linear
  perspective