Yen Na Lau, Joanna;
(2020)
Supraspinal activity patterns underpinning locomotor diversity in larval zebrafish.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
How do supraspinal circuits produce the diversity of locomotor outputs needed for an animal’s survival? To answer this question, I study the reticulospinal (RS) system of larval zebrafish, as these cells provide the main source of descending motor control. I combine two-photon calcium imaging of RS neurons with high-speed behavioural tracking to study RS activity across a range of kinematically distinct swim types. Examination of reticulospinal recruitment across different swim types has revealed unique, but partially overlapping activity patterns, suggesting that some cells encode kinematics common to multiple swim types, while others encode kinematics which are characteristic of a specific swim type. By developing regression-based encoding models which describe a cell’s activity using low-level tail kinematics, we identify “kinematic modules”. These modules contain cells with similar kinematic encoding and thus represent the core combinations of kinematic features encoded by RS activity. I find that laser ablation of cells within a module produce specific kinematic deficits without affecting shared elements of locomotion. This data suggest a circuit architecture where kinematic modules can be differentially combined to produce locomotor diversity through the context-specific recruitment of particular groups of RS neurons. I also describe a novel preparation for the imaging of fluorescent activity indicators in larval zebrafish using an acousto-optic lens microscope. This methodology allows for rapid 3D point scanning of the entire reticulospinal complex during visual stimulus presentation and behavioural tracking. The improved temporal resolution and sampling across the whole population provides an opportunity to examine the relative timing of activity between reticulospinal neurons.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Supraspinal activity patterns underpinning locomotor diversity in larval zebrafish |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/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. |
| 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 Life Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences > Neuro, Physiology and Pharmacology |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10094187 |
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