1. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.1 The Chemical Senses Olfaction and Gustation Research difficulties Pheromones Gustation (taste) –four taste qualities –flavor –tongue localization –survival significance –sensory coding

2. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.2 The Chemical Senses Olfaction (smell) –the basic smells Amoore Henning’s Odor Prism –receptor –coding –survival significance –neural pathways

3. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.3 The Chemical Senses Olfaction and Gustation –sensory systems for the detection of chemicals –olfaction (smell) detects chemicals in the air –gustation detects chemicals dissolved in a solution saliva helps to dissolve the chemical Research difficulties –hard to control amount of odorant reaching the smell receptors –very rapid adaptation –taste buds die off every 4 - 11 days

4. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.4 Pheromones Animal studies –chemical communication by both taste and smell Human studies –gender identification men - musky women sweet –babies can identify own mother’s milk by smell –family members can identify family t-shirts –Vomeronasal system role of smell is sexual attraction - the perfume industry –moose musk, and “pheromone” the perfume the McClintock effect

5. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.5 Gustation Four basic taste qualities –sweet, sour, bitter, salt Flavor –not the same as taste an apple, onion, and potato all have the same taste, they differ in flavor –flavor is composed of: taste, smell, touch (texture), temperature, color, and sometimes pain –learned preferences for flavors

6. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.6 Tongue Localization The entire surface can detect all tastes. However, the tip is most sensitive to sweet, the sides to salt and sour, the back of the tongue and the soft palate respond most strongly to bitter.

7. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.7 Survival Significance of Taste

8. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.8 Sensory Coding Across fiber pattern coding –the pattern of activity across many receptors codes for the taste –the same receptors may respond but with different relative amounts of activity –the graph shows four sample taste buds and how they might respond to each taste Specific tastes are identified in the frontal lobe

9. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.9 Olfaction Basic smells –Amoore’s seven basic smells camphoraceous pungent floral ethereal minty musky putrid –all other smells would be a combination of these –later Amoore had 14 basics, then 21 basics, etc..

10. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.10 Olfaction Henning’s Odor Prism - a graph of 6 basic smells and their possible combinations

11. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.11 Olfactory Receptor Olfactory mucosa (epithelium)

12. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.12 Sensory Coding Chromatographic theory (tentative) –spatial pattern –pattern of activity across many receptors –different odors cause activity in different locations on the olfactory mucosa No one theory has strong evidence to support it

13. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.13 Survival Significance Taste acts to detect important nutrients and to warn us about bad food or poison How might smell function to: –warn us about danger? –attract us to things that will help us survive or bring us pleasure?

14. Sensation and Perception - chemical_senses.ppt © 2001 Dr. Laura Snodgrass, Ph.D.14 Neural Pathways The olfactory mucosa is directly linked to the olfactory bulb which sends the information to the frontal lobe for identification Collaterals (copies of the signals) are send to three other structures –amygdala - where emotions are processed –hippocampus - where memories are processed –hypothalamus - processing involved in eating, drinking, and sexual behavior Smell is strongly associated with emotions, memory, eating, drinking, and sexual behavior