The mission of LECOM’s Auditory Research Center (ARC) is: Using the auditory pathways as a model system, conduct research that will enhance our understanding of the structure and function of the nervous system in health and disease. Shown in the figure below is a schematic of the human auditory pathways. The superior olivary complex [SOC] is a constellation of nuclei in the brainstem that function in sound localization, coding temporal features of sound and in descending modulation of the cochlea.

Currently, the research efforts of the ARC are guided by three broad objectives:

A. Determine the effects of developmental disorders and of prenatal teratogen exposure on structure and function of the central auditory pathways. We continue to study the cytoarchitecture of auditory neurons in the brainstems of individuals diagnosed with autism and in animals prenatally exposed to valproic acid (an animal model of autism).

Hypothesis: The hearing deficits present in autism are directly related to dysmorphology of auditory brainstem neurons and dysfunction within auditory brainstem circuits.

Projected Outcomes: The results from our study of normal and autistic brains will contribute a more thorough understanding of the neurobiology of developmental disorders and may lead to the development of learning/interventional strategies for individuals with autism. Our study of animals prenatally exposed to valproic acid provide insight into errors in axonal projections and neurochemistry and will provide a background for more detailed investigations into function on the cellular level in autism.

B. Determine the effects of age and sensory deprivation on the structure and distribution of perineuronal nets (PNN), specialization of the brain extracellular matrix. We are using an animal model to study the postnatal development of PNN, extracellular structures with implicated roles in neuronal protection and plasticity.

Hypothesis: The postnatal development of PNN in the auditory system is dependent on neuronal activity within auditory circuits and thus intimately related to the onset hearing.

Projected Outcomes: The results from this project will contribute to our understanding of critical periods and neuronal plasticity and provide background information required for the development of interventional strategies in acute and chronic brain injury.

C. Describe the neuronal morphology and neurochemistry of human auditory brainstem neurons.

Hypothesis: Despite significant interspecies variation, the human auditory brainstem is arranged according to the same basic structural and functional principles that govern all primates, carnivores and rodents.

Projected Outcomes: The results from this ongoing investigation will contribute to our understanding of the structure and function of the mammalian auditory system.

Shown above are neurons from the human medial superior olive [MSO], the most prominent of the cell groups within the superior olivary complex. The MSO is the first major site of convergence of auditory information from the right and left ears. Thus, MSO compares information from the left and right and plays an essential role in sound localization.