Lecture 18: Hypothalamus - Agression Flashcards
Compare and contrast the views of Hess, Hunsperger and Flynn on the representation of fight and flight in the hypothalamus and midbrain
Hess
- implanted electrodes in cat brains and stimulated different sites in the brain stem over a period of years.
- Identified specific sites (posterior medial aspect of hypothalamus) in the brainstem that were able to evoke naturally looking agressive behaviour in cats (sham rage)
Hunsperger
- Followed a similar method to hess - electrically stimulating the hypothalamus
- Identified discrete regions of the brain which produced discrete elements of aggressive behaviour
- defense
- attack
- flight
- gowling and hissing
- Concluded that there had to be a hierarchicahal organisation of these behaviours that can be subject to environmental modulation.
Flynn
- investigating notion of sensory motor bias
hypothalamus received somatosensory visual inputs which could guide these behaviours
“affective attack” - behaviour that were seen by hess and hunsperger
chracterized by sympathetic NS arousal
hisses/snarls, back arched and attacks
electrical stimulation of ventromedial hypothalamus nucleus was critical
“quite biting attack”
different type of aggression
cat would stalk prey and pounce on it and bite its neck
no vocalisation (no sounds)
evoked by stimulation of lateral hypothalamic nuclei
turning stimulating off: aggressive behaviour stops immediately: stimulation of hypothalamus has changed behavioural drive
this was not an aversive event (not unpleasant): cats have no memory of this behaviour
hypothalamus contains critical neuronal cirtcuity that drives 2 types of aggressive behaviour
