College
Buchtel College of Arts and Sciences
Date of Last Revision
2024-09-19 12:09:10
Major
Biomedical Science
Honors Course
71335
Number of Credits
3
Degree Name
Bachelor of Science
Date of Expected Graduation
Spring 2024
Abstract
Neurons transmit signals through an electrochemical reaction: synapses on dendrites and the cell body receive neurotransmitters, and their effect on the cell determines the signal the cell will transmit. From dendrites to axon and then to another cell at a synaptic cleft, signals can propagate, enhance each other, or inhibit other transmissions until the message is received by the target area. Understanding the science behind neural signaling and structural function begins at the level of the synapse. The neurotransmitter acetylcholine (ACh) plays a substantial role in modulating neural activity in the auditory system, but for many brainstem nuclei the source of cholinergic input is unknown. Identifying the source of ACh holds such significance because different sources are likely to perform different functions. The present study categorizes cholinergic input to the Ventral Nucleus of the Lateral Lemniscus (VNLL), one of the largest sources of inhibitory input to the Inferior Colliculus (IC), a midbrain center that processes nearly all auditory information received by the brain. Using retrograde and anterograde labeling of cholinergic cell bodies and axons, we identified three regions- the Pontomesenphalic Tegmentum (PMT), the Superior Olivary Complex (SOC), and the Lateral Paragigantocellular Nucleus (LPGi)- transmitting acetylcholine to the VNLL in mouse. Mouse models allowed for selective manipulation of cholinergic axons through viral injection of fluorescent protein in transgenic-bred mouse lines. Retrograde experiments identified cholinergic cell bodies in the three regions of interest communicating with the VNLL by labeling cells with a RetroBead marker originally injected into the VNLL followed by antibody tissue staining, and anterograde studies validated this communication pattern by labeling cholinergic axons in the VNLL coming from fluorescent injections placed in each of the three regions of interest. Axon termination patterns demonstrate the degree of communication between these areas and also suggest that individual VNLL neurons receive converging input from multiple cholinergic sources, likely to be active for different roles in modulating VNLL neurons and their responses to sound.
Research Sponsor
Dr. Brian Bagatto
First Reader
Dr. Brett Schofield
Second Reader
Dr. Quin Liu
Honors Faculty Advisor
Dr. Brian Bagatto
Proprietary and/or Confidential Information
No
Recommended Citation
Echols, Emily, "Sources and Termination Patterns of Cholinergic Input to the Ventral Nucleus of the Lateral Lemniscus" (2024). Williams Honors College, Honors Research Projects. 1896.
https://ideaexchange.uakron.edu/honors_research_projects/1896