Acetylcholine injection into the amygdala elicits vocalization in domestic pigs ( Sus scrofa)

In a pilot study we have injected the amygdala of five female pigs (age 8 weeks) with acetylcholine (ACh, 5.5 μM/20 μl) and recorded short latency utterances. The evoked vocalizations displayed the characteristics of natural screams in sonagram appearance and hearing impression. Quantitative analyses, too, revealed the similarity of the ACh-evoked vocalizations with natural screaming. The results demonstrate for the first time that aversive vocalizations can be triggered by cholinergic amygdala stimulation.