week 10 - smell

Question 1

What type of stimuli does the vomeronasal organ respond to?

Answer 1

pheromones

Question 2

phermones

Answer 2

• chemicals detected by VNO
• substance produced by animals/human

Question 3

What occurred when the VNO was removed from male rats?

Answer 3

• loss of normal sexual behavior
• attempts to mate with males and females
• unable to locate females based on odor

Question 4

Singh and Bronstad

Answer 4

• showed a relationship between men’s rating of women’s body odors and women’s menstrual cycle
• men preferred scent of women going through ovulation

Question 5

anosmia

Answer 5

lack the ability to smell

Question 6

specific anosmia

Answer 6

inability to smell specific chemicals

Question 7

What procedures have researchers used to measure the detection threshold?

Answer 7

• yes/no procedure
• forced-choice procedure

Question 8

yes/no procedure

Answer 8

• particpants are given trials with odors along with “blank trials”
• can they smell trial? respond with yes or no

Question 9

forced-choice procedure

Answer 9

• two trials given (one with odor and one without)
• participant indicates which smells the strongest

Question 10

What makes humans different from rats and dogs when it comes to odor sensitivity?

Answer 10

individual receptors are equally sensitive but the difference lies in the number of receptors

Question 11

difference threshold

Answer 11

smallest difference in concentration that can be detected between two samples

Question 12

recognitions threshold

Answer 12

concentration needed to determine quality of an odorant

Question 13

Why do researchers have a hard time mapping perceptual experience onto physical attributes of odorants?

Answer 13

• there is no specific language for odor quality
• some molecules can have a similar structure but smell different or have different structures and smell the same

Question 14

olfactory mucosa

Answer 14

• located on top of nasal cavity
• contains receptors
• odorants are carried along the mucosa coming in contact with the olfactory receptor neurons

Question 15

What is the pathway of odor information to the glomeruli?

Answer 15

odor information is converged from multiple receptor neurons (same type) and travel through axons in the ethnoid bone and are brought to the glomeruli

Question 16

Malnic experiment (combinatorial code for odor)

Answer 16

• found that odorants are coded by patterns of activation of olfactory receptors called recognition profiles through calcium imaging
• displayed the amount of receptors used for an odorant as well as their intensities

Question 17

What type of coding does Malnic’s experiment showcase?

Answer 17

odorant recognition profiles of olfactory mucosa are reminiscent of sparse coding

Question 18

What occurs when olfactory receptors are damaged?

Answer 18

lose the ability to smell

Question 19

What type of techniques are used to show how glomeruli respond to different odorants?

Answer 19

optical imaging and 2DG

Question 20

What has optical imaging research found in regards to the glomeruli?

Answer 20

• displayed activation of olfactory bulb in response to different chemicals
• adding more carbon to each related chemicals -> activation moves left
• related chemicals found in similar areas of olfactory bulb

Question 21

What has 2DG research found in regards to the glomeruli?

Answer 21

• inject substance to illuminate radioactivity which showcases neural activation
• used different odorant chemicals to showcase different areas of activity

Question 22

What type of coding does optical imaging and 2DG showcase?

Answer 22

specificity coding

Question 23

What is the pathway of signals starting from the olfactory bulb?

Answer 23

• signals are sent to primary olfactory (piriform) cortex in the temporal lobe and amygdala
• then sent to secondary olfactory (orbitofrontal) cortex in frontal lobe

Question 24

What is the role of amygdala in the smell system?

Answer 24

plays a role in emotional reactions to odors

Question 25

Rennaker experiment (piriform cortex)

Answer 25

• used multiple electrodes to measure neural responding in the piriform cortex
• found that isoamyl acetate causes scattered activation across the cortex

Question 26

What type of coding does Rennaker’s experiment showcase?

Answer 26

sparse coding

Question 27

Settler and Axel

Answer 27

• replicated Rennaker’s experiment but with optical imaging
• displayed similar results

Question 28

Wilson experiment (peppermint)

Answer 28

• measure response of neurons in the rat’s piriform cortex to two odorants
• presented a mixture of two odors (peppermine and isoamyl acetate) and a component (isoamyl acetate)

Question 29

What were the results of Wilson’s experiment?

Answer 29

with enough exposure, the piriform cortex could discriminate the mixture and the compound

Question 30

How does odor stimuli reach the olfactory mucosa from the mouth?

Answer 30

through the retronasal route

Question 31

Clamped nose experiment

Answer 31

• limits taste to only 5 primary tastes
• blocks all info from olfactory bulb from being sent to brain

Question 32

Plassmann experiment (wine)

Answer 32

• judging taste pleasantness of wine
• same level for bottles not showing a price
• higher rating for more expensive wine despite being the same as cheap wine

Question 33

O’Doherty experiment

Answer 33

• pleasantness and food-related order are influenced by satiety
• higher rating pre-satiety and lower rates post-satiety for bananas