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Module 5: Learning Objectives. Understand sensation as a process by which raw physical stimuli sent to the brain are changed into potentially useful experiences. Learn the basic mechanisms of vision, audition, balance, taste and smell, touch, and pain.
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Module 5: Learning Objectives • Understand sensation as a process by which raw physical stimuli sent to the brain are changed into potentially useful experiences. • Learn the basic mechanisms of vision, audition, balance, taste and smell, touch, and pain. • For each of the basic sensations (vision, audition, balance, taste and small, touch, and pain), explain how that sensation involves the interaction of stimuli, sensors, and the brain.
Learning Objectives cont. • Appreciate the considerable impact of cultural differences on a simple experience like tasting a common food which is considered good in some cultures and disgusting in others. • Consider the implications of placebos and the placebo effect for human psychology. • Understand the complicated dimensions of pain, not as simple as you might think. • Learn about exciting new applications of artificial senses to correct age-old problems of vision and audition.
Introduction • Electric billboard in the brain (Blind Katie) • Three characteristics of all senses (Processes) Can you explain how the 3 characteristics of all senses produce the experiences of seeing, hearing, smelling, touching, tasting, and position? • Transduction • Adaptation • Sensations versus perceptions
A. Eye: Vision • Stimulus: light waves • Invisible—too short • Visible—just right (visible spectrum) • Invisible—too long What is the visible spectrum and what makes it visible?
2. Structure and function What happens when you look at something? Can you explain the process of looking? • Image reversed • Light waves • Cornea • Pupil • Iris • Lens • Retina
h. Eyeball’s shape and laser eye surgery 1) Normal vision 2) Nearsightedness 3) Farsightedness 4) Eye surgery 3. Retina: a miniature camera-computer • Photoreceptors • Rods • Cones • Transduction • Nerve impulses, optic nerve and blind spot
4. Visual pathways: eye to the brain • Optic nerve • Primary visual cortex • Specialized cells • Stimulation or blindness • Visual association areas • PET scans reveal visual activity
5. Color vision • Making colors from wavelengths • Trichromatic theory • Opponent-process theory • Afterimage • Excited or inhibited • Theories combined • Color blindness • Monochromats • Dichromats
B. Ear: Audition • Stimulus: sound waves • Amplitude and loudness • Frequency and pitch • Measuring sound waves • Decibel • Decibels and deafness
3. Outer, middle, and inner ear • Outer ear • External ear • Auditory canal • Tympanic membrane • Middle ear • Ossicles • Hammer, anvil, and stirrup • Oval window
c. Inner ear • Cochlea • Hair cells and basilar membrane • Auditory nerve 4. Auditory clues • Calculating direction of a sound • Calculating pitch • Frequency theory • Place theory • Calculating loudness
C. Vestibular System: Balance • Position and balance: vestibular system • Semicircular canals • Sensing position of head, keeping head upright, maintaining balance • Motion sickness • Meniere’s disease and vertigo
D. Chemical Senses • Taste • Four basic tastes: sweet, salty, sour, and bitter (plus a possible new one, umami) • Surface of the tongue • Taste buds • All tongues are not the same • Flavor: taste and smell
2. Smell, or olfaction • Stimulus • Olfactory cells • Sensations and memories • Functions of olfaction What is a recently discovered function of olfaction?
E. Touch • Sense of touch • Skin • Hair receptors • Free nerve endings • Pacinian corpuscle • Brain areas: somatosensory cortex
F. Cultural Diversity • Psychological factors Although most foods cause delight, some otherwise edible substances cause disgust. What explains this phenomenon and why is it automatically translated into a facial expression? • Disgust • Cultural influence 2. Cultural influences on disgust
G. Research Focus: Mind over Body? • Definitions and research methods • Placebo • Placebo effect • Double-blind procedure • Placebo results 3. Conclusion: mind over body!
H. Pain • Pain sensations • Tissue damage • Social, psychological, and emotional factors • Gate control theory of pain • Competing messages to the brain • Pain: physical and psychological • Endorphins • Acupuncture
Endorphins • Pain reduction and addiction • Adrenal cell transplants • Acupuncture • Competing stimuli • Psychological factors
I. Application: Artificial Senses • Artificial visual system • Artificial photoreceptors • Artificial eye and brain implant • Functional vision • Kinds of deafness • Conduction deafness • Neural deafness • Cochlear implant