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Signal processing by octopus cells for acoustic and electrical hearing : a modelling study
Dissertation (MEng (Bio-Engineering))--University of Pretoria, 2016.
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| Format: | Thesis |
| Language: | English |
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2026
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| _version_ | 1867613691162132480 |
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| access_status_str | Open Access |
| author2 | Hanekom, J.J. |
| author_browse | Hanekom, J.J. |
| author_facet | Hanekom, J.J. |
| collection | Thesis |
| description | Dissertation (MEng (Bio-Engineering))--University of Pretoria, 2016. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/110142 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:40:10.037Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/110142 Signal processing by octopus cells for acoustic and electrical hearing : a modelling study Hanekom, J.J. lizablignaut@tuks.co.za Blignaut, Gertruida Elizabeth Octopus cell Cochlear implant Temporal pitch Cochlear nucleus Travelling wave delay Dissertation (MEng (Bio-Engineering))--University of Pretoria, 2016. A computational model of a single octopus cell as well as a population of octopus cells was developed. The models were used to investigate the ability of octopus cells to compensate for the travelling wave delay, remove jitter from the neural activity and encode pitch for normal hearing. Furthermore the response of octopus cells to cochlear implant (CI) stimulation with the ACE strategy was investigated to determine whether pitch can be extracted from CI stimulation in the same way as from acoustic stimulation. Their ability to extract the pulse rate from single-electrode stimulation was also investigated. The response of the octopus cells to single-electrode stimulation at different pulse rates was used to predict pulse rate difference limens, which were compared to psychoacoustic measurements found in literature. It was found that octopus cells are sensitive to the delay of synaptic inputs on their dendrites but are broadly tuned to this delay. By evaluating the jitter together with the travelling wave delay present in the activity of auditory nerve fibres (ANFs), it was determined that octopus cells may rather act as coincidence detectors, which extract common interspike intervals (ISIs) from many ANFs. The octopus cell model was found to encode the frequency of pure tones in their ISIs for pure tone acoustic stimulation. They were also found to encode the pitch of a vowel in their ISIs, which was the same as the fundamental frequency extracted from the vowel with a speech processing algorithm. The octopus cell model responded to the pulse rate of the CI stimulation and could therefore not extract the frequency of pure tones from CI stimulation in the same way as from acoustic stimulation. The entrainment of the modelled octopus cell population decreased when the pulse rate of a single electrode increased beyond 300 pps. Pulse rate difference limens were predicted from the standard deviation of the ISIs of the octopus cell population response to single electrode stimulation. The predicted difference limens were in the same range as measured values, which suggests that octopus cells may play a role in the measured perceptual limit at 300 pps. From the findings of this study it is suggested that CI stimulation strategies should be developed to encode pitch in the periodicity of their stimulation to enable octopus cells to extract pitch information from CI stimulation Electrical, Electronic and Computer Engineering MEng (Bio-Engineering) 2026-05-15T17:26:25Z 2026-05-15T17:26:25Z 17/02/13 2016 Dissertation http://hdl.handle.net/2263/110142 en application/pdf |
| spellingShingle | Octopus cell Cochlear implant Temporal pitch Cochlear nucleus Travelling wave delay Signal processing by octopus cells for acoustic and electrical hearing : a modelling study |
| title | Signal processing by octopus cells for acoustic and electrical hearing : a modelling study |
| title_full | Signal processing by octopus cells for acoustic and electrical hearing : a modelling study |
| title_fullStr | Signal processing by octopus cells for acoustic and electrical hearing : a modelling study |
| title_full_unstemmed | Signal processing by octopus cells for acoustic and electrical hearing : a modelling study |
| title_short | Signal processing by octopus cells for acoustic and electrical hearing : a modelling study |
| title_sort | signal processing by octopus cells for acoustic and electrical hearing a modelling study |
| topic | Octopus cell Cochlear implant Temporal pitch Cochlear nucleus Travelling wave delay |
| url | http://hdl.handle.net/2263/110142 |