Dunn, Soraya Louise Salahi;
(2019)
Dynamics of theta oscillations in the ferret hippocampus.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The hippocampus is a brain region with important roles in memory and spatial navigation. Theta oscillations are a prominent component of hippocampal local field potential and play a critical role in many models of hippocampal function. These models are based almost exclusively on rodent studies, where theta activity occurs mainly during running behaviour. However, active sensation in the form of whisking and sniffing at frequencies within the theta range also occur during locomotion. As such, it remains an open question whether theta is functionally linked to locomotion and/or active sensation. Here we introduce the ferret (Mustela putorius furo) as a new model species for the study of hippocampal theta. Ferrets are predatory carnivores that rely predominantly on the distal senses of vision and audition, in contrast to the proximal sensing strategies of whisking and sniffing in rodents. Ferrets and rodents share several other ethological similarities, so the impact of dominant sensory strategy can be explored. We have identified theta oscillations in the ferret hippocampus which occur at a 3-7 Hz, a lower frequency band than commonly observed in the rat (5-12 Hz). Ferret hippocampal theta showed many similarities with theta oscillations found in the rat, particularly regarding the strong relationship of theta activity with speed. While theta frequency was found to have a positive correlation with the animals’ speed, the gradient of this relationship in ferrets was roughly half that found in rats over the same speed range. Rats and ferrets were trained on comparable auditory/visual localisation tasks designed to manipulate sensory attention. Ferret theta oscillations were generally found to be continuous while the ferrets performed the behavioural task, even during immobility. Our between species comparison of behavioural correlates of hippocampal theta provide a valuable addition to the canon of hippocampal species comparisons.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Dynamics of theta oscillations in the ferret hippocampus |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2019. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. - Some third party copyright material has been removed from this e-thesis. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > The Ear Institute |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10071903 |
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