Groh Research

How do our senses work together? Our eyes and ears cooperate to help us understand our environment. We frequently perceive visual and auditory stimuli as being bound together if they seem likely to have arisen from a common source. That's why we tend not to notice that the speakers on TV sets or in movie theatres are located beside, and not behind, the screen. Research in my laboratory is devoted to investigating the question of how the brain coordinates the information arising from the ears and eyes. Our findings challenge the historical view of the brain's sensory processing as being automatic, autonomous, and immune from outside influence.

The Brain and Space

Auditory Prostheses in the Brain

Over the last several decades, auditory prostheses have revolutionized the treatment of deaf patients. However, nearly all of this success has involved prostheses placed in the cochlea, in the ear, rather than in the brain. A subset of patients cannot use a cochlear implant due to structural problems with the cochlea or due to bilateral damage in the auditory nerve. These patients can only be helped by a brain prosthesis. Yet, the current generation of prostheses placed within the brain have not been as successful as cochlear implants: patients typically are not able to understand speech well enough to use the telephone (e.g. Lenarz et al., 2001; Colletti and Shannon, 2005; Tatagiba and Gharabaghi, 2005). This is true both of implants placed in the cochlear nucleus (the more commonly used site) and the inferior colliculus (more recently investigated in a small number of patients). Why these implants have not fulfilled their promise is not clear. This project seeks to shed light on what might be going wrong and how these problems might be solved. The project focuses on an animal model, the non-human primate, and is motivated by the idea that testing in an animal model affords opportunities for combined anatomical, electrophysiological, and behavioral approaches that would be difficult or impossible to conduct in human patients.