psych 333 test 4

how many different Anosmias have been identified in humans?

80 sepcific anosmias -most common ones are steroidal must compounds identical in other species as pheromones (but no clear role for humans)

PROP/PTC is about? nontasters/supertasters is about?

PROP/PTC--->detection nontasters/supertasters---->sensitivity level

PTC tasters pleasantness vs non tasters

PTC tasters may find some food and drink (e.g. raw veggies, alcohol, caffeine) less pleasant than non-tasters

subunits

T1R1-T1R3---->umami T1R2-T1R3---->sweet T2Rx--------->Bitter (25-30 types) H+ ion ------->sour Na+ ion-------> salt (2 types)

what determines out food preferences?

a combination of genetics and culture determine our food preferences -->but here's more than just this...

info on extreme cases of fungiform papillae

normal individuals ay have as few as 5 fungiform papillae in a 6mm areas, or as many as 60

how many types of sour channels and salty channels

one type of sour channel and two types of salty channels

things that make up taste

onset/aftertaste intensity quality: pleasant: sweet, salty, unami, sour (mild-->pleasant, strong-->unpleasant), unpleasant: bitter hedonics: pleasant or unpleasant localization

receptor code for olfaction

population (pattern) code for odor

super-tasters

some individuals experience heightened taste sensations to a broad range of tastes, not just bitter

list the common types of synesthesia

sound-color synesthesia (chromosthesia) grapheme-color synesthesia effect of context number-form synesthesia

can genes be turned on or off?

specific genes can be turned on or off over course of development or by environment

thickening agents do what?

thickening agenta are pervasive additives to processed foods (e.g. guar gum, carrageenan) to increase mouth feel and thus, flavor and appeal.

odor perception fades over time because of

1. receptor adaptation (very short term) 2. cortical adaptation (medium term)--why the smell of a bakery diminishes over the course of an hour spent inside -sensitivity can be restored by brief exposure to other odors 3. cognitive habituation (long term)--why you don't detect the smell of your house unless you have been away at least a few days -shorter durations away do not restore sensitivity -this is why we do not smell out own skin/hair, except when it changes (e.g. sweating)

responses to some olfactory stimuli are hardwired... such as... (with examples)

1. smells associated with predators: rats that are bred in laboratories and have not been exposed to cats for generations show a fear response to cat odor. 2. pheromones evoke behavioral or hormonal responses: female rabbits release pheromones that trigger nursing responses in newborn rabbits -studies show some human pheromone effects but extent and importance is unclear

amygdala (subcortical)

linking odor to emotion

orbitofrontal cortex (OFC)

(secondary olfactory cortex) -in the frontal lobe =cortical area responsible for assigning affective value in response to a wide range of sensory stimuli

olfaction and gustation's overall purpose

-"gatekeepers" of the body -identify things that should be consumed for survival -detect things that would be harmful and should be rejected -cause pleasant and unpleasant affective responses -act together with trigeminal (nerve) system, which enables us to feel tastes (e.g. chilies) and smells (e.g. menthol)

stats on super tasters

-35% of women are super tasters compared to just 15% of men

weet and umami tastants are traduced by pairs of T1R-type GPCR's:

-T1RR and T1R3 fro sweet -T1R1 and T1R3 for umami

PTC/PROP info

-a member of the bitter family -individuals who have two recessive alleles are non tasters; those with either one or both dominate alleles are tasters

evolution of olfaction and emotion

-almost all species use smell or chemical reception/communication -humans may be unique in the degree to which we've replaced these with visual and auditory means -yet we still have approach/avoid and like/dislike reactions in both emotional and olfactory domains -thus, human emotion can be seen as a highly evolved, abstract, cognitive version of basic behavioral motivations instigated by the olfactory system in animals.

neural aspects of grapheme-color synesthesia

-area V4 (color processing) and Visual Word-Form area are next to each other.... -fMRI responses to letters evoke responses in V4 for syntheses but not for controls -ventral surface fMRI activity in response to letter/number (grapheme) stimuli--->in this case they synesthete, but not the normal control person, shows activation of hV4 color processing area

what else contributes to food preferences?

-cultural -experience -foods you're encouraged to like -expectations, attitudes, and beliefs -advertising

list some of the ways that genes affect eating behavior.... and health

-elderly men who are PROP tasters as more bitter had the most colon polyps, a precursor to colon cancer -fats can produce unpleasantly intense sensations to super tasters, leading them to eat fewer high-fat foods and thereby lowering their risk of cardiovascular disease -alcoholics and smokers were found to contain a lower proportion of taster than would be expected by chance, presumably because unpleasant sensations (e.g. bitterness) produced by alcoholic beverages and tobacco acted as deterrents.

central pathways for taste processing

-from the nucleus of solitary tract, taste signals travel to the ventral posterior medial nucleus of the thalamus -followed by areas in the frontal lobe; -insula (insular cortex) -frontal operculum cortex -orbitofrontal cortex

innate species-specific taste responses

-human infants show characteristic facial responses to sweet, sour, and bitter tastes (unclear about salt) -many other species also show characteristic responses, particularly to bitter and sweet

microsomatic

-humans are microsomatic =a less keen sense of smell that is not crucial to survive

compare the number of olfactory receptors that humans have and dogs have. give the percentage of brain used for this

-humans have 10-20 million and dogs have 1-4 billion -% of brain used for olfaction is about .1% for humans and about .5% for dogs

intermodal synesthesia

-interaction across sensory modalities -e.g. color-tone synesthesia

intramodal synesthesia

-interaction within one sensory modality -e.g. color-grapheme (letter/number) synesthesia

the special case of FAT

-like most protein, fat molecules are too large to stimulate taste receptors; -however, whole fat molecules stimulate the trigeminal nerve, evoking tactile sensations like oily, viscous, creamy etc... -some fat molecules may be partially broken apart int eh mouth, releasing fatty acid -recent work has shown fatty acid receptors not eh tongues of rats but status for humans is unclear -other work has shown that fat (like protein) int he gut produces conditioned preferences for the sensory properties of food containing the fat (or protein), as well as satiety signals.

macrosomatic

-many animals are macrosomatic =having a keen sense of smell that is necessary for survival

distribution of tasters and non tasters varies by sex and race how so?

-more women have lower threshold than men -more asians have lower thresholds than caucasians

why is lack of clear dimensionality with odors a thing?

-neither our perceptions nor chemistry of molecular structure are clear guides to dimensionality of odors -few odor-only english words: putid, fragrant, semlly, aromatic, pungent, stinky..?? -other odor words are borrowed from tastes, fruits, flowers etc.. in fact, most odor descriptions refer to objects -yantis suggests experts may learn better odor links with language

list the top-down and bottom-up influences of olfaction and the environment

-perceptual grouping -past experience and expectations

detecting odors (humans vs. rats, mice, and dogs) what are the fundamental differences

-rats and mice are 8 to 50 times more sensitive to odors than humans -dogs are 300 to 10,000 times more sensitive -however, individual receptors for all of these animals are equally sensitive and can respond to a single molecule of oderant -the difference lies in the number of receptors they each have (and as we'll see, the number of different types of receptors)

potentially misguided attempts at improvement of foods.

-rats on diets containing the artificial sweetener saccharin gained more weight than rats given sugary food -obesity epidemic since the rise of "low fat" foods has been the biggest public health disaster of the 20th century

is there an equivalent of a color space for odors?

-researchers have found it difficult to map perceptual experience onto physical attributes of odorants example: Hennings Color Prism --corners with the qualities putrid, ethereal, resinous, burned, spicy and fragrant --other odors located in reference to their perceptual relation to the corner qualitites -unfortunately, hennings prism has proven of little use in olfactory research *no current, widely accepting, perceptual classification of odor qualities*

olfaction and gustation compared to other senses

-simpler: no localization ability -more complex: 5 taste qualities and about 350 different olfactory receptors -combine to create new quality: flavor -piggy-back on structures with other uses: like cutaneous, but unlike vision and audition.... the nose warms and humdifies air, and tongue permits speech and swallowing. -ipsilateral cortical processing only, no contralateral -less well understood

associators

-synesthesia is experienced as mental associations, in the "minds eye" -most synesthetes are associators

projectors

-synesthesia is experienced as percepts in outside world

frontal operculum cortex does what?

-taste identity, independent of hunger, rewards, pleasantness -separate and combined areas for taste, temp, texture (including viscosity, fat texture)

things that contribute to "mouth feel"

-texture (crispness, fattiness, grittiness etc) -temperature (cold to hot) -spiciness (as from chili peppers) -coolness (as from mint) -dryness (astringency, as from unripe fruit)

info on super tasters

-those with more fungiform papillae experience the most intense taste sensations in general -they also experience the most intense sensations of oral burn(chills) and oral touch (fats, thickeners) because fungiform papillae are innervated by trigeminal somatosensory nerve fibers that convey burn and touch sensations, as well as those that convert taste sensations.

table on types of tasters. draw it.

. . . . . . . . . . . .

humans can discriminate how many odors? but what? (implications)

10K-100K odors but they cannot label them accurately. this is not a lack of olfactory sensitivity -may be caused by lack of clear dimensionality and language limitiations of odor perception

where are taste buds located

2/3 of all taste buds are located not papillae on the tongue -most numerous: fuliform papillae with no taste buds -a taste bud contains 40-100 taste cells

umami=

="good flavor, good taste" described as meaty, broth, or savory and associated with MSG -->suggested as a porting receptor -->however, umami is controversial as a basic taste sensation because: 1. there isn't a universal response to it 2. glutamate receptors int eh guy may serve the protein signaling function

specific anosmia=

="smell blindness" for one specific compound

gymnema sylvestre=

=blocks sweet taste

synsepalum dylcificum=

=changes sour to sweet

effect of context synesthesia=

=color varies with context -its not the form; its the context -attention to local or global form shifts color

face-color synesthesia=

=colors associated with individuals faces. could this be the basis of why some people perceive 'auras'?

identifying odors, recognition (discrimination) threshold

=concentration needed to determine quality or identity of an odorant (typically higher than detection thresh.)

taste-shape synesthesia=

=flavors invoke the perception of 3-dimensional shapes

sound-color synesthesia (chromosthesia)=

=individuals experience colors in response to tones or other aspects of musical stimuli (e.g. timbre, key, or volume) or other sounds

lexical-gustatory synesthesia=

=is a rare form in which words and phonemes of spoken language evoke the sensations of taste in the mouth -when colored sounds taste sweet

grapheme-color synesthesia=

=letter or numbers are perceived as inherently colored (the most common synesthesia)

Rhinecephalon=

=literally the "nose brain" -neural and evolutionary connections between odor and emotion -includes primary olfactory cortex and limbic system -most ancient part of the brain -developed first from olfactory structures only later did amygdala and other hedonic and emotion centers develop. -thus, our hedonic/emotional reactions may have had origin in smell processing

number-form synesthesia=

=numbers, months of the year, and/or days of the week elicit precise locations in space (for example, 1980 may be "farther away" than 1990), or may have colors, or have a three-dimensional view of a year as a map (clockwise or counterclockwise)

perceptual grouping

=we learn to perceive a single odor (e.g. bacon) from familiar combinations -even though there are many different component odorants and combinations of them -even in the presence of other familiar compound odors

all mammals have how many olfactory genes?

>1,000 olfactory genes, each for a different olfactory receptor type different proportions of these are actually expressed in different species and individuals. the more expressed, the better the overall olfactory sensitivity

genetics of Taste Receptors : bitterness

Bitterness and PTC (phenytlthiocarbarnide) and PROP (propylthioouracil)

genetic contributions to food preferences

PTC/PROP-taster vs. non-taster

synesthesia definition

a condition in which stimulation on one sensory dimension also give rise to an experience in a different dimension called a photism (literally, synesthesia means "together sensation") -consistent: associated are stable over time -automatic: associations are involuntary -elicited: association requires presence of eliciting stimulus, in contrast to hallucinations, dreams

the Stroop Effect=

a demonstration/test of synesthesia =it is difficult to override the written meaning of the word when naming the color of the text --Grapheme-color synesthetes suffer from the strop effect with black letters on a white background (remember the woman who had difficulty learning with colored plastic letters).

crowding task=

a demonstration/test of synesthesia =when placed in the periphery, it is difficult to identify the center number when surrounded by other numbers. But if the center number is a different color, it is easier to identify. --Given black letters on a white background, grapheme-color synesthetes identify the center number faster anymore accurately than control subjects.

each olfactory receptor neuron (ORN) expresses what?

a singel type of olfactory receptor on its cilia

Mueller et al. experiments showing specificity of different bitterness receptors

a) genetic manipulation added a gene to create mice that were sensitive to PTC, which normal mice don't taste b) genetic manipulation removed a different gene to creat mice that did not taste cyclohexamide (Cyx), which normal mice taste and avoid

PTC/PROP non-tasters

about 1/3 of us instead have recessive allele of the "PTC-gene" and have about 1,000 times higher threshold for PTC/PROP. These are called PTC/PROP non-tasters

PTC/PROP tasters

about 2/3 of us have a dominant version (allele) of a gene for a bitter receptor that produces high-sensitivity to PTC/PROP and related bitter compounds.

presynaptic cells may transmit info about what?

about all five taste dimensions by combination of sour and salt ion channels and ATP activation from sweet, bitter, and umami receptor cells

give an example of anosmias in humans

androstenone. it is a compound found in both male and female human armpit sweat. it is also a pheromone involved in mating behavior in pigs. -50% of humans have specific anosmia for adreostenone the remaining 50% detect androstenone and describe it as either: -->a sweet musky-floral scent -->or an unpleasant urine-like odor -these differences in perception are genetically determined-->anosmic 50% lack receptors for androstenone and have only pseudogens

bitter tastants are transducer by?

any of 25-30 individual T2R-type GPCRs on receptor cells -->these don't produce different bitter tastes but allow sensitivity to a wide range of bitter compounds (potential poisons)

most artificial foods include at least one _______________, showing the importance of visual cues to how we perceive food

artificial coloring

why does the ortho/retro processing distinction make sense?

because odors have difference significance if they come form the mouth or come from the outside world

types of 5 taste things and what they tell you

bitter and sour associated with foods you should try to avoid other three associated with things you should eat

each type of olfactory receptor is coded by what?

by a single gene

how are sour and salty tastants transducer?

by entering ion channels in presynatptic cells that release transmitters at synapses with cranial nerve endings

odorants are coded by what?

by patterns of activation of olfactory receptor neurons -specific receptors (and ORN) may be part of the code for multiple odorants

molecules that have similar structures can evoke what?

can evoke different pattern sod ORN activation and will smell different

neural coding for taste controversy

currently there is no agreed upon explanation for the neural coding for taste

different molecular components determine what?

determine different general areas of activation

length of related molecules determines what?

determines overlapping progression of laceration of greatest activation, left to right.

olfactory receptors in humans versus dogs

each receptor is the same sensitivity, but its that dogs have more receptors is why they're so much more sensitive

evidence for neural coding for taste

evidence has been presented for both specifically (labeled-line) coding and distributed (across-pattern) coding -someresearchers suggest that the neural coding for taste may function like the visual coding for color (distributed/pattern coding) -other researcher suggest that the neural coding for taste may function like the auditory coding for pitch (specificity/place coding)

perception of flavor=

flavor=taste+smell+feel -combination of smell, taste, tactile and temperature sensations (such as burning of hot peppers)

"gatekeeper" function of taste

function makes use of connection between immediate taste and eventual effect of ingestion of a substance

past experience and expectations

have an impact on odor perception and hedonics -conditioned taste aversions are caused mainly by odor cues paired with illness

exception form the above are______,________, and ________ that also stimulate _______________ in the nose and mouth, so we experience sensations coming from both.

horseradish, wasabi, hot mustard pain receptors

functions of tatse

however, there is not a perfect connection between tastes and function of substances, especially thanks to modern food chemistry -think about which bitter or sour foods/beveraes you like, why? -what about sugar-free sweets and fat-free foods?

what things contribute to the perception of flavor?

hunger/thirst olfaction vision audition taste "mouth feel"

specific hungers info

in our evolutionary past... -food was scarce, finding it took time and effort -specific hungers for sugar, salt and fats were adaptive (this is why we like the taste of them)

the taste of most compounds is influenced by? except what?

influenced by olfaction, but a few, such as MSG, sugar and table salt are not

olfactory epithelium (structure of the olfactory system) --order of processes

is located at the top of the nasal cavity -odorants are carried along the mucosa coming in contact with the olfactory receptor neurons (ORN) -cilia of these neurons contain the ion-channel receptor sites -humans have about 350 types of ORN, each with its own specialized receptor sites, and 10-20K ORN of each type, which project to 10-20 glomeruli for each type.

function of bitter

is usually associated with substances that are potentially harmful and can trigger automatic rejection responses

function of sweetness

is usually associated with substances that have nutritive value and triggers automatic acceptance response and anticipatory metabolic responses that prepare digestive system

optical imaging reveals what about activating the olfactory bulb

it reveals which areas are most active

list the uncommon types of synesthesia

lexical-gustatory synesthesia taste-shape face-color

Entorinal cortex

linking odor to memory

function of umami

may be associated with nutritious proteins

sensory contributions to food preferences

mouth "taste" -sweet, sour, salt, bitter, umami (fatty acids) mouth "feel"-fatty content, heat, texture pain olfactory cues -direct from environment -retronasal input to flavor stomach chemorecptors -amino acid (including glutamate) -carbohydrate -fatty acids *conditioned preferences are based on responses y stomach chemorecptors, blood sugar levels.

nontasters vs tasters

nontasters: high thresholds tasters: low thresholds

responses form taste and smell are first combined in the __________

orbitofrontal cortex (OFC)

spacial layout of olfactory bulb

pattern of activation is related to molecular structure of odorant, a coarse chmotopy

quick description of what synesthesia can be

perceiving tone with colors... letters or numbers with colors... tastes and smells with colors...

OFC also receives input from the ___________________ and the _________________________ in the visual ______ pathway

primary somatosensory cortex inferotemporal cortex (IT) what

stroop-like speed tests

reaction times for answers that are congruent with a synesthetes automatic colors are faster than those whose answers are incongruent. -e.g. like the color-coded simple math problem.

piriform (primary olfactory) cortex

represents odor identity -anterior (APC) represents features of chemical structure (stimulus features) -posterior (PPC) represents perceptual quality of odor, independent of physical stimulus (olfactory "object or category" perception)

info on research of hedonics of taste and hedonics of olfaction

research on hedonics of taste--and to lesser extent, neural physiology of taste--have been primarily supported by food industry. just as hedonics of olfaction have been primarily supported by the cosmetics and food industries

because of taste and feel of food in the mouth, the ________ smell of foods (and the flavor) is localized in the _______

retronasal mouth

fMRI studies show the brain processes smell differently if it comes form the mouth (__________) than just through the nose (________).

retronasal orthonasal

because of sensitizing central neural connections between taste and olfaction, those who experience the most intense taste sensations also perceive more intense ____________ and more ______________

retronasal olfaction intense flavor

five basic taste qualities. most can be described by the first four

salty sour sweet bitter umami

ipsilateral

sensations are processed not eh same side of the brain -->things smelled/tasted on left side are then processed on that side

Ramachandran and Hubbard's demonstration/test of synesthesia

showed that grapheme-color synesthetes are faster at finding the triangle of '2's imbedded in the background of '5's (than normal people)

brain pathways for olfaction

signals via olfactory tract go to: 1. amygdala 2. piriform cortex 3. entorhinal cortex

memory and olfaction/gustation

strong memory connection and emotion connections -olfactory (along with pain) strongests of all senses for emotion, processed by limbic system (major center for emotion and memory) -conditioned "taste" aversions are mediated by olfactory cues -remember the smells of important places or events in your early childhood.

cross-activation model (neural aspects of grapheme-color synesthesia)

supported by fMRI studies showing increased connectivity, and neural volume specific to these areas -->V4 (color processing) and visual-word-from area

G-protein coupled receptors (GPCR) are for what?

sweet, umami, and bitter tastants. these have larger molecules.

function of sour

taste indicates the presence of acids (H+ ion concentration) which may be associated with spoilage/fermentation

function of salty

taste indicates the presence of sodium (Na+), which is needed for normal bodily functions. people may seek this out (crave?) if sodium deficient

taste receptor types and their cranial nerve fibers

taste receptor types: 1. identity is established 2. likely one type per taste receptor cell cranial nerve fibers: 1. specificity of receptor signals is uncertain 2. labeled-line or across-pattern fiber models -evidence is ambiguous

characteristics of tasters

tasters tend to be more finicky eaters: tend to dislike foods high in bitter compounds, such as veggies

acquired synesthesia

temporary or longer-term synesthesia can result form brain injury, epilepsy, drugs (esp. psychedelic drugs)

congenital synesthesia

tends to run in families but... -genetic mechanisms are not known -family members may have different synesthesias -sex differences are disputed: some studies suggest females>>males; random population studies show no difference -overal incidence: random population studies show .5% to 4% of population

odor stimuli from food in the mouth reaches the olfactory musosa through what route?

the restronasal route

controversy about PTC tasters and super tasters

there have been controversy about the relation between PTC-tasting and super tasting. It now appears that they are independent; non-PTC-tasters may be super tasters for tastes other than bitter

linking chemical structure to types of semlls

there is no simple relationship between molecular structure of an odorant and its perceived odor -some molecules with similar shapes have very different smells -some similar smells come form molecules with different shapes.

G-protein couples receptors (GPCR) do what?

they are on receptor ells that release ATP into extracellular space. All have same intracellular signaling mechanism. -->knocking out this mechanism knocks out all signaling of sweet, umami, and bitter -ATP directly stimulates cranial nerve endings and presynaptic cells

talk about the re-generation of olfactory and gustation receptors

they have constant neurogeneiss of receptors -lifetime 5-7 weeks for olfactory cells -and 1-2 weeks for taste receptor cells

any area where there's taste buds are sensitive to all of tastes. true or false?

true

the five responses to taste are innate. true or false?

true

without color cues, we are much leads accurate in identifying the flavor of an unknown fruit juice. true or false?

true

you eat more of the "non-fat" and artificial sweetener food than food with normal sugars and fats because they don't tell your body that you're full like the normal food would. true or false?

true

contrary to popular belief, different parts of the tongue do not have more taste receptors of specific types. true or false?

true. however, tastes may still appear to be localized because of interaction with somatic cues

what causes the "cross-talk" between different sensory areas in the brain?

two ideas: 1. failure to "prune" congenital cross-modal synaptic connections 2. reduction of inhibition of normal cross-modal feedback from higher brain centers

list the types of synesthesia

types: intramodal intermodal associators projectors names (common): sound-color grapheme effect of context number-form names (uncommon): lexical-gustatory taste-shape face-color

onset of synesthesia

typically by early childhood but awareness that others don't also experience it may lag

pseudogenes

unexpressed genes -do not produce any olfactory receptors

compare color vision and taste

vision: 1. 3 cone receptors 2. multiple ganglion/LGN neurons that combine cone signals in various ways 3. cortical processing compares these inputs to ultimately construct 4 hue categories and their combinations 4. missing one cone types causes missing color categories taste: 1. 5-6 non-bitter and 25-30 bitter taste receptors 2. multiple cranial taste neurons combine recptor signals in various ways 3. cortical processing compares these inputs to ultimately contract 5 tastes categories and their combinations 4. missing one taste receptor causes missing taste categories.

what happens without the taste and feel signals from the mouth?

we do not experience flavor, and smell sensation may be reduced

orbitofrontal cortex does what?

where taste and smell signals first meet -now also pleasant need, reward value, flavor-specific satiety

molecules that evoke similar patterns of ORN will what?

will smell similar (olfactory me tamers)

what does super-tasters appear to be associated with?

with higher density of fungiform papillae on the tongue, and , presumably, higher density of taste receptors

can you be any combination of PTOP/PTC and non tasters/taster?

yes! see the 4x4 chart

can increasing taste stimuli increase intensity of smells?

yes. adding sugar (pure taste) to pear juice increases the intensity of pear sensation, which is mediated by smell -but this only works for familiar taste/odor combinations. Adding salt does not increase the pear sensation