(a physical process)

Stimulation of our sense organs by features of the outer world

The activation of sensory receptors by external physical stimulus energy

(a mental process)

How your brain organizes and interprets sensory information in a meaningful way

  analysis that begins with the sense receptors that send information up to the brain

–     That is, sensation just transduces a physical signal directly into a neural impulse the brain can later interpret for meaning

Perception often includes a meaning beyond what exists in the physical stimulus

brain stops paying attention to constant, unchanging stimuli

Cognitive and Top-down

Trichromatic Theory

Says that the patterns of activity in 3 different cone types creates normal color perception

red green blue

Opponent Process Theory

Proposes FOUR primary colors arranged in pairs:

red-green

blue-yellow

When one color is activated, the other is inhibited (in the particular point of the visual field that cell is processing).

 in basilar membrane and contains receptor cells

On the basilar membrane in the cochlea

–     soundwaves set basilar membrane in motion

–     Hair cells fire when the wave causes them to bend

Airborne molecules dissolved in the mucus in the nose

–  Attach to the olfactory receptors

–  Trigger a neural impulse

Gate-control Theory of pain

–  Addresses both sensory  AND cognitive factors

–  Pain involves an emotional, top-down component

–  spinal cord contains pain “gates”

–  “gate” opens when small fibers are activated

–  Nociceptor signals (tissue damage)

–  Cognitive signals from unpleasant emotions

So how do we STOP pain?

–  “gate” closes when large fibers are activated

o   Sensory signals other than nociceptors

o   Cognitive signals from pleasurable emotions

o   Chemicals

–  Endorphins and their antagonists “kill” pain by blocking the pain signals from entering the brain

Your “activity” sense

             – tells you the location of your individual body parts in relation to the ground and each other.

Mostly located in joint tissues - proprioceptors

Vestibular sense

–  “whole body” sensations of motion, balance, position

–  arise from fluid motion in inner ear

–  Vestibular canals