Jos J. Eggermont

Professor Emeritus



Hotchkiss Brain Institute

Research and teaching

Research activities

My research comprises most aspects of audition with an emphasis on the electrophysiology of the auditory system in experimental animals, and is specifically focused on the role that is played by neural synchrony in the coding of complex (e.g., speech like) sounds in the auditory cortex. For that purpose extracellular single-unit recordings are made with electrode arrays (8 or 16 electrodes) simultaneously from 25-50 neurons from the auditory cortex of cats and kittens in response to a wide variety of complex stimuli. The data are analyzed with respect to both neural interaction, and single unit and population stimulus-response relationships. We developed an animal model of tinnitus to further our understanding of this disorder and, by comparison with the effects of external sounds of similar nature, to investigate how normal and pathological sound sensations are encoded in the central nervous system and the role of cortical reorganization played herein. I currently focus on the effects of long-term non-traumatic sound exposure on cortical activiry and organization. These effects occur at sound levels well below the safe standards for occupational noise exposure, which are based solely on hearing loss and not on hearing problems. We have shown that stimulating continuous or intermittently, to mimic occupational/recreational noise exposure interspersed with quiet periods (sleep), with particular sounds produces long-lasting decreases in the cortical representation of these sounds. This is expected to affect the perception of communication sounds, and may also lead to hypersensitivity for sounds with frequencies at the edge of the exposure spectrum, as well as to tinnitus (without the usual comorbid hearing loss). Extensive parametric studies into these effects are planned for the coming years.


Retired effective July 1, 2013