Topic 4.4: smell and taste

chemical senses

olfaction (smell) ands gustation (taste) work together to enhance liking or disliking of some foods.  sense receptors are stimulated by chemicals (rather than by light or sound waves) 

Odours

• Odours are airborne chemicals that interact with the lining in our nasal passages.  

• 5 Basic tastes: 

1. Sweet 

2. Salty 

3. Sour 

4. Bitter 

5. Umami 

Smell and taste receptors

• Each olfactory neuron contains a single type of receptor, which recognizes odorants based on their shape.  

Lock and key model

• similar to NT's. 

• On the papillae of the tongue are taste buds for each base taste.  

Supertasters

•  have more taste buds, taste flavours more intensely.  

• Smell and taste senses converge in the orbitofrontal cortex.  

Pheromones

• Odourless chemicals that serve as a social signal to members of the same species. 

• Importance of pheromones for humans is unclear. 

• The typical pheromone detection system that mammals use (vomeronasal organ) is not well developed in humans.  

 

Learned responses

 Use classical conditioning to show preferences for smells and tastes are learned through association. Ex: An odor repeatedly paired with a sweet taste can become more pleasant.  

emotion and memory

 Direct link between the olfactory bulb and amygdala/hippocampus is studied to understand why smells are so powerfully tied to emotion and memory. Conditioning studies also explore how the emotional significance of  a taste/smell is learned.  

Perceptual studies

• Researchers test how factors like hunger, prior experience, or even time of day affect taste and smell perception. For example, they may investigate how different 

concentrations of an odor affect physiological responses like heart rate.