Case Study: Effects of Ultrasonic Vocalizations on Rat Behavior and Place Cell Remapping in the Hippocampus

Spatial information is known to be encoded in the hippocampus, and small changes in the environment can alter the way that it is represented by our hippocampal place cells in a process called remapping. Hearing is an important sense that can be used to orient ourselves and react to the environment accordingly. In this case study, a rat model is used to test the effects of emotional auditory stimuli, behaviorally significant ultrasonic vocalizations (USVs) (50 kHz, emitted during play; 22 kHz, emitted during danger), on rat behavior on a linear track and place cell remapping in the hippocampus. Behaviorally, it was found that the rat slowed down significantly going in one direction on the track when exposed to these novel USVs. On a neuronal level, the firing rates of place cells trended to increase as the rat was exposed to the 50 kHz sound but not the 22 kHz sound. Some place cells remapped, and those changes either persisted or reverted after the auditory stimuli were turned off, while others did not