[{"degree_awarded":"MS","ddc":["570","596","005"],"abstract":[{"lang":"eng","text":"Left–right alternation is a defining feature of spinal locomotor circuits, yet the level of neuronal\r\ndetail required to generate and maintain this pattern remains unclear. This thesis investigates how\r\nmodels spanning multiple levels of abstraction—from biophysically detailed Hodgkin–Huxley (HH)\r\nneurons to adaptive integrate–and–fire (I&F) formulations and synfire-chain modules—can account\r\nfor the generation of fictive swimming in the spinal cord of the Xenopus laevis tadpole. The guiding\r\nhypothesis is that a small set of neuronal mechanisms is sufficient to reproduce the essential features\r\nof rhythmic alternation, and that moving between modeling scales helps distinguish core principles\r\nfrom biological detail.\r\nA minimal bilateral HH network comprising only four canonical neuron classes—excitatory\r\ndescending interneurons (dINs), inhibitory commissural interneurons (cINs), ipsilateral inhibitory\r\ninterneurons (aINs) and motoneurons—served as a biophysical proof of concept. Tuned to reproduce\r\nexperimentally observed firing modes, the model demonstrated that rebound-prone dIN excitability,\r\ncontralateral inhibition and modest electrical coupling are sufficient to generate stable alternating\r\nactivity, even in very small networks. These results motivated the transition to simpler models\r\ncapable of efficient analysis and scaling.\r\nAdaptive exponential I&F (AdEx) neurons were calibrated to physiological recordings using\r\nsimulation-based inference, yielding tonic and phasic/rebound templates that preserved the key\r\ndynamical signatures of the HH model. Phase-plane analysis clarified the mechanisms underlying\r\nsingle-spike responses and rebound firing in dINs. At network level, the I&F models robustly\r\nreproduced left–right alternation, while highlighting constraints on synaptic kinetics and adaptation\r\nneeded to avoid multi-spike responses.\r\nFinally, a synfire-chain framework provided a complementary, timing-centric perspective, demonstrating how precise spike synchrony, synaptic delays and minimal inhibitory coupling can generate\r\nalternating left–right sequences in a feedforward setting. Together, these approaches converge on a\r\ncommon conclusion: rebound-prone ipsilateral excitation combined with precisely timed contralateral inhibition constitutes a sufficient substrate for alternating spinal rhythms.\r\nBy integrating bottom-up and top-down modeling strategies, this thesis provides a unified, extensible framework for studying spinal pattern generation. The results show that essential locomotor\r\ndynamics can be captured across multiple abstraction levels, offering both mechanistic insight and\r\npractical tools for future data-driven investigations of spinal circuit development, robustness and\r\nmodulation."}],"date_published":"2025-12-09T00:00:00Z","status":"public","file":[{"file_name":"tadpoleAdEx.zip","date_updated":"2026-01-02T13:05:07Z","checksum":"9e3b6b73f8cbec2c3687d17fe8e30410","relation":"source_file","file_size":566072368,"file_id":"20919","creator":"awilson","date_created":"2026-01-01T17:26:30Z","access_level":"closed","content_type":"application/zip"},{"date_created":"2026-01-04T12:58:49Z","creator":"awilson","access_level":"open_access","content_type":"application/pdf","file_size":7170097,"relation":"main_file","file_id":"20923","checksum":"13f4c0d33923e9d5c9d56731345cf21d","success":1,"file_name":"Masters_Thesis_Alexia_Wilson_FINAL_pdfA.pdf","date_updated":"2026-01-04T12:58:49Z"}],"user_id":"ba8df636-2132-11f1-aed0-ed93e2281fdd","oa":1,"publication_status":"published","author":[{"orcid":"0000-0001-6191-1367","last_name":"Wilson","first_name":"Alexia C","full_name":"Wilson, Alexia C","id":"5230e794-15b2-11ec-abd3-e2d5335ebd1d"}],"title":"Modelling the spinal cord of a tadpole : Exploring different ways to model the spinal cord in the Xenopus frog","year":"2025","_id":"20735","oa_version":"Published Version","month":"12","article_processing_charge":"No","alternative_title":["ISTA Master's Thesis"],"date_updated":"2026-04-07T12:36:08Z","OA_place":"publisher","has_accepted_license":"1","supervisor":[{"full_name":"Vogels, Tim P","id":"CB6FF8D2-008F-11EA-8E08-2637E6697425","first_name":"Tim P","last_name":"Vogels","orcid":"0000-0003-3295-6181"},{"first_name":"Lora Beatrice Jaeger","full_name":"Sweeney, Lora Beatrice Jaeger","id":"56BE8254-C4F0-11E9-8E45-0B23E6697425","orcid":"0000-0001-9242-5601","last_name":"Sweeney"}],"corr_author":"1","language":[{"iso":"eng"}],"publication_identifier":{"issn":["2791-4585"]},"file_date_updated":"2026-01-04T12:58:49Z","date_created":"2025-12-08T09:49:41Z","department":[{"_id":"GradSch"},{"_id":"TiVo"},{"_id":"LoSw"}],"page":"110","day":"09","publisher":"Institute of Science and Technology Austria","doi":"10.15479/AT-ISTA-20735","related_material":{"record":[{"status":"public","relation":"part_of_dissertation","id":"13097"}]},"type":"dissertation","citation":{"ama":"Wilson AC. Modelling the spinal cord of a tadpole : Exploring different ways to model the spinal cord in the Xenopus frog. 2025. doi:<a href=\"https://doi.org/10.15479/AT-ISTA-20735\">10.15479/AT-ISTA-20735</a>","chicago":"Wilson, Alexia C. “Modelling the Spinal Cord of a Tadpole : Exploring Different Ways to Model the Spinal Cord in the Xenopus Frog.” Institute of Science and Technology Austria, 2025. <a href=\"https://doi.org/10.15479/AT-ISTA-20735\">https://doi.org/10.15479/AT-ISTA-20735</a>.","short":"A.C. Wilson, Modelling the Spinal Cord of a Tadpole : Exploring Different Ways to Model the Spinal Cord in the Xenopus Frog, Institute of Science and Technology Austria, 2025.","mla":"Wilson, Alexia C. <i>Modelling the Spinal Cord of a Tadpole : Exploring Different Ways to Model the Spinal Cord in the Xenopus Frog</i>. Institute of Science and Technology Austria, 2025, doi:<a href=\"https://doi.org/10.15479/AT-ISTA-20735\">10.15479/AT-ISTA-20735</a>.","ista":"Wilson AC. 2025. Modelling the spinal cord of a tadpole : Exploring different ways to model the spinal cord in the Xenopus frog. Institute of Science and Technology Austria.","apa":"Wilson, A. C. (2025). <i>Modelling the spinal cord of a tadpole : Exploring different ways to model the spinal cord in the Xenopus frog</i>. Institute of Science and Technology Austria. <a href=\"https://doi.org/10.15479/AT-ISTA-20735\">https://doi.org/10.15479/AT-ISTA-20735</a>","ieee":"A. C. Wilson, “Modelling the spinal cord of a tadpole : Exploring different ways to model the spinal cord in the Xenopus frog,” Institute of Science and Technology Austria, 2025."}},{"tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"article_number":"1146449","department":[{"_id":"LoSw"}],"file_date_updated":"2024-01-03T13:33:21Z","date_created":"2023-05-28T22:01:04Z","external_id":{"pmid":["37180760"],"isi":["000984606200001"]},"corr_author":"1","date_updated":"2026-04-07T12:36:07Z","has_accepted_license":"1","publication_identifier":{"issn":["1662-5110"]},"intvolume":"        17","quality_controlled":"1","language":[{"iso":"eng"}],"publication":"Frontiers in Neural Circuits","related_material":{"record":[{"id":"20735","relation":"dissertation_contains","status":"public"}]},"type":"journal_article","day":"26","publisher":"Frontiers","doi":"10.3389/fncir.2023.1146449","volume":17,"citation":{"mla":"Wilson, Alexia C., and Lora B. Sweeney. “Spinal Cords: Symphonies of Interneurons across Species.” <i>Frontiers in Neural Circuits</i>, vol. 17, 1146449, Frontiers, 2023, doi:<a href=\"https://doi.org/10.3389/fncir.2023.1146449\">10.3389/fncir.2023.1146449</a>.","apa":"Wilson, A. C., &#38; Sweeney, L. B. (2023). Spinal cords: Symphonies of interneurons across species. <i>Frontiers in Neural Circuits</i>. Frontiers. <a href=\"https://doi.org/10.3389/fncir.2023.1146449\">https://doi.org/10.3389/fncir.2023.1146449</a>","ista":"Wilson AC, Sweeney LB. 2023. Spinal cords: Symphonies of interneurons across species. Frontiers in Neural Circuits. 17, 1146449.","ieee":"A. C. Wilson and L. B. Sweeney, “Spinal cords: Symphonies of interneurons across species,” <i>Frontiers in Neural Circuits</i>, vol. 17. Frontiers, 2023.","short":"A.C. Wilson, L.B. Sweeney, Frontiers in Neural Circuits 17 (2023).","chicago":"Wilson, Alexia C, and Lora B. Sweeney. “Spinal Cords: Symphonies of Interneurons across Species.” <i>Frontiers in Neural Circuits</i>. Frontiers, 2023. <a href=\"https://doi.org/10.3389/fncir.2023.1146449\">https://doi.org/10.3389/fncir.2023.1146449</a>.","ama":"Wilson AC, Sweeney LB. Spinal cords: Symphonies of interneurons across species. <i>Frontiers in Neural Circuits</i>. 2023;17. doi:<a href=\"https://doi.org/10.3389/fncir.2023.1146449\">10.3389/fncir.2023.1146449</a>"},"oa":1,"file":[{"content_type":"application/pdf","date_created":"2024-01-03T13:33:21Z","creator":"dernst","access_level":"open_access","file_id":"14729","file_size":6667157,"relation":"main_file","success":1,"checksum":"7efd06de284a28e91e97127611a9c3fd","file_name":"2023_FrontiersNeuralCircuits_Wilson.pdf","date_updated":"2024-01-03T13:33:21Z"}],"isi":1,"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","author":[{"last_name":"Wilson","orcid":"0000-0001-6191-1367","first_name":"Alexia C","full_name":"Wilson, Alexia C","id":"5230e794-15b2-11ec-abd3-e2d5335ebd1d"},{"id":"56BE8254-C4F0-11E9-8E45-0B23E6697425","full_name":"Sweeney, Lora Beatrice Jaeger","first_name":"Lora Beatrice Jaeger","orcid":"0000-0001-9242-5601","last_name":"Sweeney"}],"license":"https://creativecommons.org/licenses/by/4.0/","project":[{"name":"Development and Evolution of Tetrapod Motor Circuits","grant_number":"101041551","_id":"ebb66355-77a9-11ec-83b8-b8ac210a4dae"}],"publication_status":"published","article_type":"original","acknowledgement":"This work was supported by the ERC Starting grant, ERC-2021-STG #101041551.","ddc":["570"],"status":"public","scopus_import":"1","date_published":"2023-04-26T00:00:00Z","abstract":[{"lang":"eng","text":"Vertebrate movement is orchestrated by spinal inter- and motor neurons that, together with sensory and cognitive input, produce dynamic motor behaviors. These behaviors vary from the simple undulatory swimming of fish and larval aquatic species to the highly coordinated running, reaching and grasping of mice, humans and other mammals. This variation raises the fundamental question of how spinal circuits have changed in register with motor behavior. In simple, undulatory fish, exemplified by the lamprey, two broad classes of interneurons shape motor neuron output: ipsilateral-projecting excitatory neurons, and commissural-projecting inhibitory neurons. An additional class of ipsilateral inhibitory neurons is required to generate escape swim behavior in larval zebrafish and tadpoles. In limbed vertebrates, a more complex spinal neuron composition is observed. In this review, we provide evidence that movement elaboration correlates with an increase and specialization of these three basic interneuron types into molecularly, anatomically, and functionally distinct subpopulations. We summarize recent work linking neuron types to movement-pattern generation across fish, amphibians, reptiles, birds and mammals."}],"month":"04","pmid":1,"article_processing_charge":"Yes","title":"Spinal cords: Symphonies of interneurons across species","oa_version":"Published Version","year":"2023","_id":"13097"}]