Philip H. Smith

Philip Smith
Professor, Department of Neuroscience
(608) 262-0291


Ph.D. Purdue University

Research Focus:

Auditory processing in the thalamus and cortex

Research Strength:

Neural Circuits

Research Description:

I have studied/published data on the structure and function of all stations of the auditory central nervous system including auditory nerve, auditory brainstem, inferior colliculus, medial geniculate and auditory cortex. My present primary interest is in the mechanisms used by an auditory brainstem nucleus, the medial superior olive (MSO) to process binaural information.

Binaural hearing is thought to play a key role in the development of speech and language perception because the normal development of the brain’s binaural circuitry requires the proper activation of these inputs. Besides being instrumental in the development of normal circuitry, recent evaluation of bilateral cochlear implant patients has shown some improvements in sound localization, speech intelligibility and speech in noise perception. However, many patients are unable to exploit temporal binaural differences that provide the main cue for sound localization and speech perception in the presence of multiple sound sources. One of the major impediments for our lack of understanding as to why this is the case is that we still do not have a complete understanding the basic brainstem circuitry involved in binaural processing and the mechanisms used by this circuitry to extract the critical auditory cues. The MSO is the initial binaural site in the auditory pathway where major excitatory inputs activated by the two ears converge. It is by far the most prominent of the auditory brainstem nuclei in the human superior olivary complex. Interestingly, virtually all children with autistic spectral disorder (ASD) have auditory related dysfunction and the MSO is the most severely and consistently malformed brainstem nucleus in the autistic brain. All of these observations would indicate that a more thorough understanding of MSO structure and function is critical.


Please see PubMed for most recent publications