College
Buchtel College of Arts and Sciences
Date of Last Revision
2025-12-11 06:52:10
Major
Biomedical Science
Honors Course
Sr Honors Project in Biology 003 (BIOL 499-003)
Number of Credits
3
Degree Name
Bachelor of Science
Date of Expected Graduation
Spring 2026
Abstract
The inferior colliculus is a nucleus in the auditory midbrain that plays an important role in sound and speech processing through how it encodes temporal precision. Temporal precision depends on the balance of inhibition and excitation within the IC. This balance degrades during aging. Age-related changes in synapses have been described in the lemniscal IC as a contributing factor for this imbalance. However, it is unknown if aging affects synapses throughout the non-lemniscal IC in a similar manner. We sought to determine this by examining the dorsal cortex of the IC. The ICd is a non-lemniscal nucleus that is well known for its extensive innervation by the auditory cortex. Electron microscopy techniques were used across age groups of young 2–3 months, middle 19–21 months and older age 27–29 months Fischer Brown Norway rats. Our data demonstrates a small loss of GABAergic synaptic density in middle age, with a significant loss during older age. We also demonstrate decreases with age in terminal area and mitochondrial ultrastructure across both synaptic types. Collectively our data suggest a net loss of inhibition in the ICd. Thus, the balance of excitation and inhibition in the ICd is likely altered and may contribute to factors underlying age-related hearing loss.
Research Sponsor
Dr. Brian Bagatto
First Reader
Dr. Jeffrey Mellot
Second Reader
Dr. JJ Ramirez
Honors Faculty Advisor
Dr. Brian Bagatto
Proprietary and/or Confidential Information
No
Recommended Citation
Tenney, Kylee M.; Smallridge, Dakota; Barach, Gillian; Singh, Gurveer; Beskitt, Erin; Busby, Justine; Duncan, Syllissa; Wawrzyniak, Alexa; Vega, Brenda; Tokar, Nick; Ohl, Andrew; Young, Jesse; and Mellott, Jeffrey, "Age-related Ultrastructural Differences in the Dorsal Cortex of the Inferior Colliculus in the Fischer Brown Norway Rat" (2026). Williams Honors College, Honors Research Projects. 2071.
https://ideaexchange.uakron.edu/honors_research_projects/2071