Just as a musician can train to more sharply distinguish subtle differences in pitch, mammals can improve their ability to interpret hearing, vision, and other senses with practice. This process, which is called perceptual learning, may be enhanced by activating a major nerve that connects the brain to nearly every organ in the body, a new study in mice shows. Led by researchers at NYU Langone Health, the investigation centers on the vagus nerve, which carries signals between the brain and the heart, digestive system, and other organs.
Experts have long explored targeting this nerve with mild electrical pulses to treat a wide variety of conditions ranging from epilepsy and depression to posttraumatic stress disorder and hearing disorders. Results of such efforts have been mixed, however, and the underlying mechanisms that might lead to improved hearing had until now remained unclear. To more closely examine whether vagus nerve stimulation can boost perceptual learning, the study team trained 38 mice to tell apart musical tones.
At first, performance improved for all animals, which made fewer and fewer mistakes over time. However, while those without the treatment maxed out after about a week of training, rodents that received nerve stimulation continued to get better at the task, making roughly 10% fewer errors on average for most tests than they did prior to simulation. In addition, mice in this group made half as many mistakes as their counterparts on the most challenging a.