THE EFFECTS OF GAP JUNCTIONS AND INHIBITION ON SYNCHRONIZATION OF BIOPHYSICALLY DETAILED NEURAL NETWORK MODELS OF BUSHY CELLS OF VENTRAL COCHLEAR NUCLEUS
| dc.contributor.advisor | Bruce, Ian | |
| dc.contributor.author | Yayli, Melih | |
| dc.contributor.department | Electrical and Computer Engineering | en_US |
| dc.date.accessioned | 2025-04-30T18:30:12Z | |
| dc.date.available | 2025-04-30T18:30:12Z | |
| dc.date.issued | 2025 | |
| dc.description.abstract | The cochlear nucleus is the first stage in the central auditory nervous system (CANS) that receives information from auditory nerve fibers (ANFs). Sound identification and localization cues are extracted here and propagated to the upper levels of the CANS. One of the main cell types of the ventral cochlear nucleus is the bushy cells which can be divided into two subtypes as globular and spherical bushy cells (GBCs and SBCs). Bushy cells receive excitation from ANFs and inhibition from D-stellate and tuberculoventral cells via chemical synapses. Additionally, bushy cells are connected via electrical synapses known as gap junctions and form clusters. One of the main features of bushy cells is enhancing the synchronization behavior seen in ANFs. Although coincidence detection can be the underlying mechanism for the GBCs to show this behavior, SBCs’ synchrony enhancement mechanism is still unclear. In this thesis, biophysically detailed neural network models of SBCs and GBCs are built to investigate the effect of gap junctions on the excitability and the synchronization behavior of GBCs and SBCs. Current injection simulations show that gap junctions substantially affect the excitability of the bushy cell models and allow the spread of excitation within and between the cell clusters. Simulations made with more realistic synaptic inputs indicate that inhibition and gap junctions strongly affect the synchronization of the model SBCs and GBCs. Although the effects of the inhibition on synchronization is non-monotonic, the effects of gap junctions on the synchronization found to be clearer. A grid search is done to investigate the effects of the inhibition, gap junctions, and strength of excitation on the synchronization of bushy cell models and a set of parameters is hand-picked to fit the model results to the recorded physiological data. | en_US |
| dc.description.degree | Doctor of Philosophy (PhD) | en_US |
| dc.description.degreetype | Thesis | en_US |
| dc.description.layabstract | The cochlear nucleus (CN) is an integral part of sound processing in the brainstem. One of the main cell types of the CN, bushy cells, extracts crucial sound localization cues. Apart from the excitation and inhibition bushy cells receive through chemical synapses, they are also connected via electrical synapses called gap junctions. Although previous studies investigate the effect of gap junctions on cell behaviors in other parts of the brain, their impacts on bushy cells are yet to be explored. Our studies use biophysically detailed neural network models to determine how bushy cells process incoming sound stimuli. Our simulations show that the gap junction connections have a substantial effect on the excitability of bushy cells and the spread of excitation between bushy cells. Gap junctions also contribute to the synchronized firing behavior in bushy cells, while the inhibition’s effect on the synchronization is found to be non-monotonic. | en_US |
| dc.identifier.uri | http://hdl.handle.net/11375/31592 | |
| dc.language.iso | en | en_US |
| dc.subject | Cochlear Nucleus | en_US |
| dc.subject | Bushy Cells | en_US |
| dc.subject | Gap Junctions | en_US |
| dc.subject | Synchronization | en_US |
| dc.subject | Inhibition | en_US |
| dc.title | THE EFFECTS OF GAP JUNCTIONS AND INHIBITION ON SYNCHRONIZATION OF BIOPHYSICALLY DETAILED NEURAL NETWORK MODELS OF BUSHY CELLS OF VENTRAL COCHLEAR NUCLEUS | en_US |
| dc.type | Thesis | en_US |