week 5 (olfactory) Flashcards
(14 cards)
name: ways of testing olfactory psychophysics (4)
1. detection
⤷ detect odour or not
2. discrimination
⤷ telling diff. between odours
3. recognition
- recog. that they are familiar with odour
4. identification
⤷ hardest to do
name: methods for odour detection and discrimination (3)
1. staircase method
- odourant is increasing in increments until reports smelling smth for a few times
2. magnitude estimation task
- sniff diff. conc. of an odour and asked to rank on intensity
3. triangle test
- sniff 3odours 2 same 1 diff.
- need to find the diff. one
question: what are limitations to staircase method in olfactory methods?
- pattern recognition
- oversaturating receptors -> adaptation
- can’t control how much chem. is breathed in
question: what are factors that affect detection thresholds for olfactory?
- gender
⤷ fem. > males
⤷ fem. can change with menstrual cycle
⤷ fem. have larger olfactory bulbs - age
⤷ older = decreased number of olfactory neurons - experience
⤷ initially anosmic people can become sensitive after repeated exposure
question: what are factors that temporarily affect detection thresholds for olfactory?
- attention
⤷ detect more when consciously focusing on smelling
⤷ reduces distractions - alcohol
⤷ light use increases sensitivity
⤷ heavy use impairs it - marijuana
⤷ can stimulate appetite by increases smell sensitivities
question: why is identifying an odour harder than recognition?
- no visual cues
- can’t find the words to describe olfactory exp.
- theories:
⤷ words = very disconnected bc smell not relayed through thalamus
⤷ processing in diff. hemisphere (language = left, smell = right)
⤷ piriform/olfactory cortex isnt connected to language processing networks - recog = easier bc long lasting
⤷ nostalgia
⤷ connected to hippocampus and memories
question: what are factors that affect odour identifiation?
- age
⤷ less olfactory neurons - sex
⤷ diff. for diff. scents - genetics
⤷ indiv. variation in how many and which olfactory receptors are expressed in epithelia q
question: difference between long term and short term olfactory adaptation?
SHORT TERM
- bc of receptor adaptation
- cross-adaptation = reduction in detection following expore to another odourant
- takes less than 20mins to reverse
LONG TERM
- bc of processing by olfactory sys. in brain
- cognitive habituation: long-term exposure to odour -> no longer has ability to detect the odour
- takes weeks to reverse
name + explain: types of anosmias in olfaction (5)
-
anosmia = complete loss of smell
⤷ genetics, infections, head trauma -
hyposmia = reduced perception
⤷ infections, injury, toxin exposure - specific anosmia = unable to smell particular odour
-
parosmia = distortions in odour quality
⤷ ex. going from liking smell to not liking -
phantosmia = odour perception in absence of odourants
⤷ cacosmia = olfactory hallucinations in aversive smells
explain: shape pattern theory
- odourants and olfactory recep. have diff. shapes
- odourant will be detected by specific OR to the extent that it fits into that OR
- intensity changes which recep. are activated
- odourants can fit several recep. but preferential for 1
name: an example of support for the shape pattern theory
- stereoisomers
⤷ same atoms but mirror images can small completely diff. - specific anosmias can be explained by the missing ORs
name: problem with shape pattern theory
- some smells can be recreated by 1 chemical
- 1 chem. can make the same odour image of many chem.
question: what influences olfactory hedonics?
- familiarity
- intensity
- genetics
- upbringing
explain: aromatherapy
- manipulation of odours to influence mood, psychological well being, physiological correlates of emotions (ex. blood pressure)
- truth: odours can elicit beneficial emotional, behaviour, physical effects but only if its been assoc. with the corresponding emo. before
⤷ ex. therapeutic effect is explained by the emotions assoc. with the scent
