Mammalian vocalizations require precise timing and control over a variety of muscles. Our project addresses four aspects of vocalization control in mammals: (i) We will further characterize the circuits that form the sound pattern generator in the brainstem. This work is a continuation of our previous VPG mapping work using cooling and large-scale recordings. This work will be carried out on anesthetized animals, in which calls are elicited by midbrain stimulation. (ii) We will investigate how these brainstem circuits are controlled by the periaqueductal gray (PAG). In this part of the project, we will combine viral tracking with large-scale recordings of the PAG and brainstem in awake animals. This part of the project focuses on the anatomical and activity-based interactions of the PAG and brainstem. (iii) In the third part of the project, we will attempt to understand how population activity in the PAG predicts vocalizations. (iv) In the final part of our project, we will investigate how vocalizations and the PAG coordinate playfulness in rats. In both humans and rats, play fighting and tickling are initiated less frequently and are less enjoyable when vocalizations are absent. We will investigate how vocalization-mediated playfulness is mediated by PAG activity.