Cornell Psych 205: day05

8/14/2019 Cornell Psych 205: day05

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Chemical Senses

Lucretius - simulacranose, tongue, & vomeronasal organ

volatility, adsorbability, soluability

issues about primaries - sensory qualities

coding -labeled line (Mller)cross-fiber patterning

3 criteria1. physical mixtures of secondaries from

primaries (Newton)

2. receptor-specificity (M

ller)3. psychological/cultural salience

brain structures -triune brain - central core, limbic system, cortexrule of opposition (decussation)

flavor


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Lucretius (99-55 BCE)De Rerum Natura (On the nature of things)

objects exude likenesses of themselves (Epicurus -->simulacra), or copies

This occurs in all modalities (not just vision)

essentially correct in a way


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1. Taste

structures - papillae, buds, innervationpathway - chorda tympani

thalamus

insula, frontal operculumtheories - chemical, shape or valencecoding & primaries

salt - ionic, Na+ Cl-

sweet - large, organic AH,Bbitter - largesour - H+

anomalies - ageusia, hypogeusia, & supertasters


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the tongue


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exchange of axons

of receptors within

papillae


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enervation of tongue; cranial nerves (12 in all);

and taste pathway

olfactory nerve (1st cranial nerve)

optic nerve (2nd)trigeminal nerve (5th) touch, temperature, pain

from front of tongue

facial nerve (7th) --- taste, chorda tympani

vestibulocochlear (8th)glossopharyngeal (9th) touch, temperature, pain

from the back of tongue


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right hemisphere

left side oftongue

decussation


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theories - chemistry, shape, or valence (electrico-chemical)

coding - how are taste qualities coded ?Mller - separate receptors, separate neurons

labeled linessome other strategy?

primaries (Aristotle 4+, Fernel, 1581, 4+, etc.; rhwall, 1891, 4)

salt - ionic Na+ Cl-sweet - large, organic AH,B (3 gap)

bitter - largesour - ionic H+

umami - monosodium glutamateflavor enhancer (mild nerve toxin?)


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what are primaries?

3 Criteria used historically:

1. Physical mixing to make all secondaries Newton

2. Receptor specificity

physiological attunement-- labeled lines Mller

3. Cultural salience [Cutting]


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Primaries

salt -sweet -

bitter -sour -

Evidence formixture of all

other tastes: NONEis chocolate a combination of these?are anchovies and fresh fries combinations

of these?


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Primaries

salt -sweet -

bitter -sour -

Evidence forreceptorspecificity?

no labeled lines; Pfaffman, 1940sinstead, cross-fiber patternings


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Primariessalt - Romans offered salt to their gods

salt licks (Salzburg) and salt trade

condiments & royalty

sweet - sugar (17th-18th cent)

bitter - beer (?-19th cent), coffee (16th-18th cent)sour - acids (citrus fruits)

Evidence forculturalsalience

chocolate - 17th-18th century, today French eat 20 kg/yr


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anomalies -

ageusiainability to taste

hypogeusia

decreased abilityto taste

supertasters

above normalability to taste

(PROP)

(hypergeusia)


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18 individuals


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2.Olfactionstructures - turbinate bones, cribiform plate, olfactoryepithelium , olfactory bulbpathway - olfactory nerve (1st cranial nerve)

limbic system

olfractory & orbito-frontal cortexbut nondecussating

theories - chemical - vibrationalstereochemical (lock & key)

electrochemicalcoding & primaries

anomalies: anosmia, hypnosmia, specific anosmia


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3 also vastly interconnected


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1. nondecussating

2. does notgothrough thethalamus

3. also vastly interconnectedwith limbic system--amygdala& hippocampus (Proust)


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4. little memory decay;no short term/long termdistinction


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theories of olfactory stimulation (coding)

what produces the adequate stimulus?

chemical - vibrational

stereochemical - shape (lock & key)

electrochemical - ions

probably all correct to various degrees


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Primaries?

Zwaardemakers Odor Classification Scheme

1. Ethereal ethyl ether, chloroform, acetone

2. Aromatic camphor, cloves, menthol, mint3. Balsamic orange blossoms, lilac, vanilla

4. Amber/musk ambrosia --> fruit of the gods

5. Allicaceous garlic, hydrogen sulfide, iodine, onion

6. Burnt roasted coffee, tobacco smoke, tar7. Hircine goaty, sweat, cheese, cats urine

8. Repulsive some orchids, marigolds, bedbugs

9. Nauseous rotten meat, feces, vomit (sea sickness)


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Primaries?

1. Physical mixing to make all secondaries

not at all clear2. Receptor specificity

some based on molecular size and shape

(~1000 different receptor types?)

3. Cultural salienceyes --> camels breath


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anomalies:anosmia - inability to smell

hypnosmia - decreased ability to smell

specific anosmia - a smell-blindness toparticular odorants


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Individual Differences in Olfaction

National Geographic Smell Survey (1986)

scratch & sniff card with microencapsulated odorantsappeared in the September 1986 issue and was sent to

10.5 million subscribers.

Surveys were returned by 1.4 million readers; 200,000were excluded from outside the US; others because they wereyounger than 13.

Wysocki & Gilbert (1989)


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>1,100,000 people


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chronic nasal infection;

calcification of cribiformplate


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the storyof truffles

new

scale on

ordinate


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Social Functions of Olfaction

we sweat (1. cooling function, 2. eliminating waste)eccrine glands (2-3 million)

water, salts, urea, ammonia

(byproducts of protein breakdown)we produce odors through glands

in fossae (our pits) and on facehair acts as a wick for these substances

(maximize surface area while minimizing volume)

sebaceous glands --> sebum (thick, clear, oily secretion

rich in fatty acids)biological purpose : to waterproof fur (human scalp),largest at roots of silkiest hairsdormant until puberty --> acne

apocrine glands -->but secretions have no odor(more later)


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distribution of apocrine

glands, with apologies toMichelangelo


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link between odor and identity --> rodentsboars breath in humans - androstonone

through food in humans: in Mato GrassoDesana --> game huntersTapuya --> fisher peopleTukano --> farmers

vegetariansJapanese --> called Europeans bata kusai (stinks of butter)

Peoples of European and African ancestry havelarge collections of sebaceous glands

Peoples of Asian ancestry have little to none


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Angstgeruch - the smell of fearpalmar glands (not sebaceous or apocrine) of hands and feet

SkunksLophiomys - an African rodent of the Ruwenzoris

behavior like a skunk

odorless secretions that leave one dry-mouthed & dizzy(more later)


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Olfaction and other systems

link between odor and major histocompatibilitycomplexes (MHCs) -- chemical compoundsthat represent the structure of the immune system

a T-shirt study1.women rate men's T-shirts as more attractive with

maximally different MHCs2.women taking birth control pills rate men's T-shirts

as more attractive with maximally similar MHCs

rationale: vestige of our forebears

Lucretius -- we exude simulacra (immune systemlikenesses) of ourselves


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but is it truly Olfaction?

1st cranial nerve -- olfaction5th cranial nerve -- trigeminal

touch, pain, some aspects of the tongue

& vomeronasal organ


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Adolph Butenandtresearch on human hormones --> hormon Gr. to excite

forced to decline Nobel Prize, 1939

switched fields

The silkworm mothbombykol (Butenandt, 1959)

pheromones(coined by Karlson & Lscher, 1959)--> pherein Gr. to transfer

+ hormon


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Silkwormmoth

female

male


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Pheromones -communication of sexual and other informationby chemicals through the air


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3. Vomeronasal organ (animals)

Jacobsons organ

another chemical, epistemic channel

soluable, nonvolatile

--> nearly direct contact needed


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Vomeronasal organ(Jacobsons organ)


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Vomeronasal sensitivity

no odor quality, no smellprobable functional relation to apocrine glands

whose secretions are odorless

responses

babies hair - secretion of natural opiate (endorphins)that inhibits aggression

many aspects regarding sex & reproductionmenstrual synchrony, boars breath,

aspects MHC reception


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Chemical Senses

Lucretius - simulacra --> we exude copies of what we arenose, tongue, & vomeronasal organvolatility, adsorbability, soluability

issues about primaries - sensory qualitiescoding - labeled line (Mller) --> wrong for chemosenses

cross-fiber patterning --> correct for chemosenses3 criteria

1. physical mixtures of secondaries fromprimaries (Newton)

2. receptor-specificity (Mller) for chemosenses3. psychological/cultural salience --> most important

brain structures - ancient old newtriune brain - central core, limbic system, cortexrule of opposition (decussation) --> but not olfaction

Cornell Psych 205: day05

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