Two vocalization-related subregions in the midbrain periaqueductal gray of the guinea pig

Vocal communications are well-developed in guinea pigs: they emit a separation call when isolated from the conspecifics, and vocalize mating calls during sexual activities. Similar calls were induced by the electrical stimulation of the midbrain periaqueductal gray (PAG) and the locations where the separation and mating calls were induced were segregated in the PAG. The morphological findings demonstrated that the PAG subregion where the separation call was induced receives massive input from the anterior cingulate cortex (which is related to social attachment behavior), while the subregion where the mating call was emitted has inputs mainly from the medial hypothalamus (related to sexual behaviors), suggesting that guinea pigs used multiple neuronal networks for various species-specific calls.