title: The effects of external stimuli on the emotional-aversive response evoked by intrahypothalamic carbachol injections.
abstract: The aim of this investigation was to examine the effects of threatening (the sight and barking of the dog) or "Neutral" (flash and tone) stimuli on the emotional-aversive response evoked by direct intracerebral application of carbachol in cats. Unilateral microinjections of carbachol in 10 microgram doses and 2 mu1 volume into anterior hypothalamic/preoptic area caused a full-blown emotional response with marked vocalization. All stimuli which might be threatening for cats caused a significant increase of vocalization. "Neutral" stimuli of comparable intensity were without effect. To investigate the effects of stimulation intensity two clocks: low and loud (difference of 27 dB), were used. The loud click significantly increased vocalization level while the low click of the same intensity as a dog's barking had no significant influence on the carbachol-induced response. Cholinergic stimulation of the anterior hypothalamic/preoptic area seems to be specifically responsible for the obtained change of perception towards increased sensitivity to any potentially threatening alteration of the environment.
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D002217:Carbachol / Q000008:administration & dosage / Q000494:pharmacology*; D002415:Cats; D004644:Emotions / Q000187:drug effects*; D005260:Female; D007031:Hypothalamus; D007032:Hypothalamus, Anterior; D008297:Male; D008845:Microinjections; D010775:Photic Stimulation; D011301:Preoptic Area; D014785:Vision, Ocular; D014828:Vocalization, Animal / Q000187:drug effects
chemical_list: D002217:Carbachol