OLFACTIONIMPORTANCE

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OLFACTION--IMPORTANCE

• Anosmia
• General
• Specific
• We are constantly smelling
• Link between smell and memory
• Link between smell and emotions

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Anosmia
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SMELL--USES

• for identity, recognition
• to lure and to arouse sexual partners
• to identify food sources
• to repell (skunks)
• How do humans compare with other animals
  regarding these four uses?

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OTHER USES OF SMELL

• Use of smell by the retail industry
• new car smell
• fresh leather smell
• environmental fragrancing
• Perfume industry
• masking unpleasant body odors
• attract, allure (or repel if poorly applied)

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PHEROMONES

• Use of sex attractants to lure insects into traps
• Androstenone, humans and pigs
• Cats that rub against your legs
• Cats and dogs sniffing behaviors

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OLFACTION

• Detection of volatiles
• Effects of temperature, molecular wt.
• We are extremely sensitive to some compounds
• And less sensitive to others

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OLFACTORY FUNCTIONING

• Nostril dominance (cycles)
• Nasal mucosa
• Life cycle of olfactory receptor cells (5-8
  weeks)
• Receptor proteins on the cilia

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CODING BY NEURONS

• Again, evidence for both labeled line and pattern
  theories
• Neural message goes from cilia to receptor cell
  bodies, down axons, to olfactory bulb (resembles
  retina) and thence to olfactory brain.
• Compared to visual system, very little is known
  about functioning of odor detection.

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AROMA PRIMARIES

• Hennings smell prism
• an effort to simplify
• There is little evidence for primaries

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STEREOCHEM. THEORY OF AROMA DETECTION

• Proposed by Amoore, who postulated 7 primary
  odors
• ethereal, camphoraceous, musky, floral, minty,
  pungent, putrid

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ODOR PERCEPTION AND GENDER

• Women are much better than men at odor
  recognition
• Differentiating gender by odor

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WHAT IS FLAVOR?

• The combination of retronasal aromas and taste
• Which is more important for identification of a
  food--retronasal aromas or taste?
• Answer retronasal aromas

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Retronasal Aroma Flavor
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OLFACTION--THE DUAL SENSE

• Foods that smell repulsive but that taste good
• e.g., limburger, roquefort
• Foods that smell great but taste bad
• e.g., coffee
• Rozins experiment with odor identification

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ODORS AND MEMORY

• Olfactory wiring is to the limbic system and to
  primary olfactory cortex
• Emotions are very much tied up with olfaction and
  the limbic system

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ODORS AND MEMORY--EXAMPLES

• Example motherly love
• somatosensory cues (warmth, softness)
• smell of mother (mammalian mothers and children)
• Marcel Prousts madeleine
• Perfume makers masters of olfaction
• Physicians use smell for detecting disease

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ODOR IDENTIFICATION RESEARCH

• We are capable of identifying 6-22 indiv. aromas,
  given a great deal of practise
• We are capable of identifying a maximum of 36
  commonly experienced aromas (mixtures)
• For best identification,
• frequent exposure
• associate with a name
• get immediate feedback

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ADAPTATION

• Acuity quickly falls to 30 of original level
• Explains why the first bite is the best
• Also explains concept of menu and menu courses
• Perfumes wearing them requires adaptation or
  youd go crazy.
• When adaptation is dangerous (gas)
• Adaptation occurs in brain (evidence)

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CROSS-ADAPTATION

• One aroma causes adaptation to another
• similar odors (e.g. floral perfumes) cross-adapt
• dissimilar odors (e.g. piney vs sulfuraceous) do
  not cross-adapt nearly as much
• Experminents
• 1. sniff lemon, peanut butter, then lemon
• 2. sniff lemon, then lime, then lemon

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INFORMING COMPOUNDS (or FICs)

• Nootkatone
• Et-2-Me Butyrate
• Furfuryl Mercaptan
• tr-2-cis Octadienal
• 1-octene-3-ol
• Diacetyl
• Methyl anthranilate
• 2-Methoxy-3-isobutyl pyrazine

• Grapefruit
• Apple
• Coffee
• Cucumber
• Mushroom
• Butter
• Concord grape
• Bell Pepper

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THE G.C.--A PRIMITIVE NOSE
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FLAVORS 1. Pine tree 2. Putrid 3. Acetone 4.
Blue cheese 5. Green grass 6. Detergent 7.
Almond 8. Musky, putrid
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Preferences Acquired, Not Hard-Wired