Background
Rats emit 50-kHz ultrasonic vocalizations (USVs) to communicate positive emotional states, and these USVs are increasingly being investigated in preclinical studies on reward and motivation. Although it is the activation of dopamine receptors that initiates the emission of 50-kHz USVs, non-dopaminergic mechanisms may modulate calling in the 50 kHz frequency band. To further elucidate...