Gustation Flashcards
Differences between mammals and insects gustatory organs?
Mammals = have a single gustatory organ in the head.
Insects = have taste organs distributed over their body.
Taste pathways in the CNS
Taste neurons send axons directly to the CNS.
Most sensory neurons in legs and wings project to the ventral nerve chord.
Sensory neurons from the proboscis project to the subesophageal zone (SEZ).
Gustatory neurons and motor neurons aborize in the SEZ = sensorimotor centre for feeding.
Types of receptors involved in gustation of the fly?
Gustatory = sweet and bitter
Ionotropic = salt
pickpocket 28 = PPK channel family = water detection
How does detection of potential food usually begin?
With activation of gustatory neurons on the legs.
What does fly do upon detection of sucrose with leg gustatory neurons?
Fly stops walking and extends proboscis.
What does detection of appetitive substance cause?
Detection with probosics labellar neurons.
Causes proboscis extension and ingestion.
What does detection of bitter compounds cause?
Causes proboscis retraction.
Future Questions?
More detailed understanding of gustatory circuits.
Determine how quality and location of taste compinds is encoded, how taste detection elicits feeding behaviour.
How taste circuits modified by learning and other sensory stimuli.
How taste detection is integrated with other sensory stimuli, e.g odors to influence behavioural decision.
What are the chemical sensors in mammals and how are they grouped?
TRCs = Taste receptor cells
Grouped in taste buds, distributed into different papillae of tongue and oral cavity.
What types of cells are contained in taste buds?
3 types of TRCs (types 1,2, and 3)
Basal cells (involved in genesis of new TRCs)
What are the cranial nerves and what do they do?
3 cranial nerves (VII, IX, X)
They innervate different parts of the oral cavity and convey taste information to the rNST.
What does the rNST do?
Interconnects other CNS regions.
Receives input from:
pontine parabrachial nerve (PBN)
lateral hypothalamus
gustatory cortex (GC)
central amygdala
reciprocally from the caudal (visceral) NST
Order of projection?
PBN projects to VPMpc, prokects to GC, projects to OFC.
OFC neurons project and receive inputs from dorsolateral prefrontal cortex.
Mammalian Taste Receptor Cells and Signal Transduction.
Taste signal transmission between tongue and brain.
