Pheromone Processing - Invertebrates Flashcards
Describe the CNS of arthropods
Dorsal anterior brain (pair of fused ganglia)
Ventral nerve cord with segmental ganglia
Describe the PNS of arthropods
2-4 pairs of lateral nerves for each ganglion
Where is the principle centre for motor control in arthropods?
The subesophageal ganglion
What is the most telling property of an odorant or pheromone which determines where in the brain it will be processed?
Carbon chain length
What are the 3 kinds of sensilla?
Trichoid (hairlike)
Basiconic (peglike)
Coeloconic (recessed peglike)
How do pheromones access underlying OSNs of the sensillum?
There is a pore at the end of the sensillum
Why do pheromones or odorants need pheromone binding proteins?
Need to cross the lipophilic barrier of the sensillum
At the level of an OSN, how many synapses away from the CNS are we?
One
How many unique ligand types is an OSN capable of binding?
1
Some OSNs are capable of sensing (1) information in addition to chemosensory information
Mechanosensory
The glomeruli of the antennal lobe are made of this substance
Neuropil
Where is convergence of information happening during sensory processing of pheromones?
At the level of the glomerulus
How does convergence of information increase sensitivity to a ligand?
Increases the redundancy of information reaching the brain
What is a macroglomerular complex?
A glomerulus which is enlarged and deals with important pheromones
What are the lateral and medial tracts of projection neurons?
Projection neuron tracts which go from the antennal lobe all the way to the mushroom bodies - 2 different pathways carrying information from one brain area to the next
Where are Kenyon cells located?
In the mushroom bodies
What is contained within the mushroom body calyces?
The dendritic fields of Kenyon cells
How can the area of the mushroom bodies be increased?
Some insects have folds in the calyces for increased volume
Where are the 2 synapses in pheromone processing in invertebrates?
1st: Between OSN and PN in glomerulus of antennal lobe
2nd: Between projection neuron and Kenyon cell in calyces of mushroom bodies
As dosage of pheromone increases, so does (1) in OSNs
Frequency of action potentials
At the level of the OSN, stimulus is encoded by (1), not (2)
Firing rate, not timing or temporal patterning of spikes
At the level of the antennal lobe, the rate code of OSNs ins converted to…
Temporal code: which glomeruli are activated and when
Stimulus at the level of the projection neurons of the antennal lobe is modulated by…
Local inhibitory neurons (release GABA)
Information from all activated glomeruli of the antennal lobe is combined, a process known as…
Summation
