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Predatory aggression induced by hypothalamic stimulation: modulation by midbrain periaqueductal gray (PAG)
S K Manchanda1, A Poddar, S Saha
1Department of Physiology, All India Institute of Medical Sciences, New Delhi, India.
Neurobiology (Budapest, Hungary)
|January 1, 1995
Summary
Electrical stimulation of the hypothalamus can induce predatory aggression in cats. Midbrain enkephalinergic mechanisms, specifically in the periaqueductal gray (PAG), modulate this attack behavior.
Area of Science:
- Neuroscience
- Animal Behavior
- Neuropharmacology
Background:
- The hypothalamus plays a crucial role in regulating motivated behaviors, including aggression.
- The periaqueductal gray (PAG) is a midbrain structure involved in the expression of defensive and offensive behaviors.
Purpose of the Study:
- To investigate the role of midbrain periaqueductal gray (PAG) mechanisms in modulating hypothalamic-induced predatory attack behavior in cats.
- To assess the effects of lesions and drug microinjections in the PAG on the excitability of hypothalamic attack loci.
Main Methods:
- Electrical stimulation of hypothalamic regions to elicit predatory aggression in cats.
- Electrocoagulative lesions and microinjections of delta-alanine-methionine enkephalin (DAME) and naloxone in the dorsal PAG.
- Stimulus-response (S-R) curves were used to quantify behavioral components of attack.
Main Results:
- Anodal lesions in the dorsal PAG increased the excitability of hypothalamic attack sites.
- Microinjection of DAME into the dorsal PAG suppressed somatomotor attack components and inhibited affective displays.
- Naloxone administration at the same sites facilitated attack behavior and reversed DAME's inhibitory effects.
Conclusions:
- Midbrain enkephalinergic pathways within the PAG are involved in the neural circuitry of predatory aggression.
- These findings highlight the modulatory role of the PAG in hypothalamic-driven attack behaviors.