Lecture 2: taste and smell Flashcards

1
Q

What are taste and smell?

A

Chemical compounds

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2
Q

Outline Wedekind 1995

A

*dirty t shirts

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3
Q

Outline McCulloch et al 2006

A

*dogs can pick up diseases in people through their sense of smell

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4
Q

How do we recognise smell?

A
  • combination receptor code

- each odour has a different spatial pattern

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5
Q

How does adaptation to recognising smells work?

A

Receptors stop firing as much if repeatedly exposed

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6
Q

How does adaptation to recognising smells work?

A

Receptors stop firing as much if repeatedly exposed

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7
Q

Taste

A
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8
Q

Taste sensitivity

A

**
some people increased liking with increased sweetness, others prefer intermediate levels (Callaghan and Weingarten, 1992).

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9
Q

Taste buds

  • how long do they last?
  • what happens to food molecules
  • how many tastes per cell?
A
  • Only last about 10 days
  • Food molecules dissolve in the mouth and bind to receptors.
  • One cell – one taste.
  • Tastes buds all capable of receiving different tastes (several cells).
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10
Q

Taste: what is involved in neural relay

A

• Cranial nerve fibres relay this information to the brain.
– Preference for one taste by may respond to others.
• To thalamus – gustatory cortex (anterior insula and frontal operculum).
• Or straight to amygdala- emotion!

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11
Q

How does cortical processing work?

A

• Cortical cells can respond to all flavours.
• Scott and Plata-Salaman (1999)
– Cortical responses to taste.
– Single cell recordings – tuning preference.
– 1= responds to all tastes, 0=only responds to one taste.
– Average = 0.7
Most cortical cells respond to a variety of tastes but have a preference for one.

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12
Q

Taste adaptation

  • what happens
  • what happens to water taste after having salt solution on tongue
A
  • *
  • can adapt to specific tastes, eg rate tastes as less sour over time

-salt solution on tongue for a while makes pure water taste sweet

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13
Q

What is flavour?

A
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14
Q

What percentage of taste comes from how we think it smells?

A

Between 75-95%

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15
Q

What is retronasal olfaction

A

=smells coming from the mouth

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16
Q

What is orthonasal olfaction

A

=via the nose

17
Q

Murphy et al (1977)

A

**

18
Q

Stevenson et al (2004)

A

Caramel odorants can enhance sweetness but also diminish sour tastes.
Oral referral
Olfactory and gustatory stimuli are congruent – get flavour experience
Smell may be “referred” to the mouth.

19
Q

Taste and Fizz

A

**

20
Q

Taste and music

A
  • music influencing choice of wine purchase
  • enjoyment of sugar can be enhanced by loud music
  • oysters eaten while listening to the ‘sound of the sea’ taste significantly more pleasant than oysters eaten while listening to farm yard nosied
21
Q

Understanding multi sensory integration

A

**

22
Q

Taste primaries

A

= a theory of taste coding based on the idea that perceived taste can be broken down into basic qualities, each uniquely associated with activity in a specific neural pathway

23
Q

Umami

A

A Japanese word meaning ‘good taste’, recent evidence indicates that it is a fifth basic taste quality

24
Q

Olfactory receptor neuron

A

A specialised neutron that produces electrical responses to door molecules

25
Q

Olfactory epithelium

A

A patch of muscoous membrane in the roof of the nasal cavity containing olfactory receptor neurons, in humans contains 6 million receptor neurons

26
Q

Free nerve ending

A

A brand of a sensory nerve cell that has no specialised receptor process, but is embedded directly in tissue

27
Q

Mitral cell

A

A neuron in the olfactory bulb that receives signals from olfactory receptor neurons and relays them to the brain, 50,000 mitral cells in the human olfactory bulb

28
Q

Olfactory bulb

A

A mass of neural tissue protruding from the brain behind the nose, which conveys neural signals from the olfactory epithelium to the brain

29
Q

Olfactory glomerulus

A

A dense, spherical accumulation of dendrites and synapses, where approx 200 olfactory receptors make contact with a single mitral cell

30
Q

Primary olfactory cortex

A

The cortical destination of mitral cell fibres, thought to mediate perception of smell

31
Q

Amygdala

A

A necleus lying deep in the brain, forming part of the limbic system, involved in emotional, sexual and automatic responses

32
Q

Anosmia

A

Lack of sensitivity to door

33
Q

Taste receptor

A

A chemoreceptor cell found on taste buds in the mouth, tongue and throat, there are 50-150 recpetors on each bud

34
Q

Taste bud

A

A cluster of cells embedded in the skin of the tongue and mouth, housing taste receptors. The human tongue contains approx 5000 taste buds