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.
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
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.
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
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.