The inner ear is connected to the brain by two kinds of sensory neurons and is controlled by two neuronal feedback systems. The Liberman Lab studies all four of these pathways, in normal hearing and in sensorineural hearing loss, particularly that caused by acoustic overexposure.

One important focus of his recent research has been the effects of efferent feedback systems on the auditory system. His work has shown that this efferent feedback helps us discriminate sounds in a noisy environment and also protects the inner ear from damage following overexposure to loud sounds. His work uses a variety of approaches from systems neuroscience to cell and molecular biology.