Aggression Flashcards
In crayfish, which neurotransmitters play a role in aggression?
Serotonin = flexor stimulated to get an aggressive posture
Octopamine = extensor and flexor stimulated to get a submissive posture
A subordinate crayfish perfused with serotonin will be more aggressive. A dominant crayfish perfused with octopamine will show reduced aggresion.
In crayfish, what is determining status?
If a dominant or isolated crayfish lateral giant neuron is in contact with serotonin, you enhance the amount of β-EPSPs in the neuron while in the case of a subordinate crayfish, serotonin inhibits β-EPSPs. The NS tuning and status vary with social experience depending if the crayfish was winning during aggressive encounters or not.
In fruit flies, what chemical promotes aggression?
The male pheromone (z)-7-tricosene released by organs called œnocytes (oe). When those organs are deficient, you need this pheromone to get aggression instead of courtship in male-male interactions.
Do fruit flies have dominance hierarchies?
Yes, they do. Dominant flies will have a longer access to a food source and will demonstrate a more aggressive behavior (more lunges). Also, flies remember with who they fought and if they lost, they don’t try again.
What is the fighting style of male fruit flies vs. females?
Males: mostly lunge, sometimes do a shove and a wing threat, rarely a headbutt and a lunge-like.
Females: combination of shove and headbutt and a little of lunge-like
The behavior is sexually dimorphic and females do not show hierarchies like males: they won’t have consecutive wins.
In fruit flies, what is happening when a male has the nervous system of a female (expresses fruF)?
He will fight like a female. The reverse occurs in females which fight like male when they express the FruM gene instead of the feminine one.
What is particular with P1 and P2 neurons of fruit flies?
They are sexually dimorphic neurons. In males, when P1 is activated at low levels in the presence of another male, you get aggression, courtship in the presence of a female. However, when it is overstimilated, you will get courtship no matter what. Therefore, those neurons regulate both aggression and courtship.
What are the evidences in fruit flies that you have the choice between courtship vs. aggression? (2)
Female 227 promoter masculinized: you get courtship like males and fighting like females. Seems that only the circuit leading to courtship has been masculinized.
Tachykinin: neurons releasing this peptide regulate aggression and also express the fruitless gene.s. But tachykinin is not produced a lot by females. When you KO, aggression is affected, but not courtship.
What is the reaction of a male mouse to a male intruder that is castrated? Castrated perfumed with male urine? Why?
Castrated = no aggression Urine = aggresion
Aggression is mediated by olfaction because when you remove vomeronasal olfaction (induce mutation in Trp gene), the male does not react to the intruder.
Where is aggression processed in mice brains? What happens?
In the ventromedial hypothalamus which is sexually dimorphic (males have more progesterone receptor-expressing neurons).
1. When you remove some of those neurons, you reduce aggression.
2, When males court, activity of VMH shuts down. When they fight, it’s a really active region.
3. When VMH is inactivated, aggression is reduced
4. When you activates VMH cell, you get aggression
What protein is common between mice and fruit flies for the aggressive behvaior?
Tachykinin. If mice don’t have the receptor, aggression is greatly reduced. Once again, it is not involved in courtship.
How do you get inhibition of VMH in mice? Activation?
I: Infect with a virus carrying ivermectin receptor chloride channel.
A: Infect with a virus carrying channelrhodopsin so activated by light.
Do mice show dominance?
Yes they do, it is a transitive one. It is controlled by the strength of synapses in the medial prefrontal cortex (more activity when dominance) which are expressing glutamate receptors. When you have more glutamate receptors, you have a greater rank (synapse is stronger). When you have less glutamate receptors, you get down in hierarchy.
What proteins play a role in human aggressive behavior?
Serotonin which is metabolized with monoamine oxidase. When you have monoamine oxidase KO, you get aggressive people.
