Ultrasonic vocalizations (USVs) in rats are thought to contain ecological signals reflecting emotional states. These USVs are centered on 50-kHz. and frequency modulation (FM) is hypothesized to indicate positive emotion; however. results from recent studies are inconsistent with this hypothesis. https://www.diegojavierfares.com/discount-Los-Angeles-Rams-NFL-Womens-Bottom-Line-Crop-Top-p11321-best-save/