---
OA_place: publisher
_id: '20735'
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."
alternative_title:
- ISTA Master's Thesis
article_processing_charge: No
author:
- first_name: Alexia C
  full_name: Wilson, Alexia C
  id: 5230e794-15b2-11ec-abd3-e2d5335ebd1d
  last_name: Wilson
  orcid: 0000-0001-6191-1367
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>'
  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>'
  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>.'
  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.'
  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.'
  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>.'
  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.'
corr_author: '1'
date_created: 2025-12-08T09:49:41Z
date_published: 2025-12-09T00:00:00Z
date_updated: 2026-04-07T12:36:08Z
day: '09'
ddc:
- '570'
- '596'
- '005'
degree_awarded: MS
department:
- _id: GradSch
- _id: TiVo
- _id: LoSw
doi: 10.15479/AT-ISTA-20735
file:
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  creator: awilson
  date_created: 2026-01-01T17:26:30Z
  date_updated: 2026-01-02T13:05:07Z
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  file_name: tadpoleAdEx.zip
  file_size: 566072368
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- access_level: open_access
  checksum: 13f4c0d33923e9d5c9d56731345cf21d
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  creator: awilson
  date_created: 2026-01-04T12:58:49Z
  date_updated: 2026-01-04T12:58:49Z
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  file_name: Masters_Thesis_Alexia_Wilson_FINAL_pdfA.pdf
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  success: 1
file_date_updated: 2026-01-04T12:58:49Z
has_accepted_license: '1'
language:
- iso: eng
month: '12'
oa: 1
oa_version: Published Version
page: '110'
publication_identifier:
  issn:
  - 2791-4585
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '13097'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Tim P
  full_name: Vogels, Tim P
  id: CB6FF8D2-008F-11EA-8E08-2637E6697425
  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
  last_name: Sweeney
  orcid: 0000-0001-9242-5601
title: 'Modelling the spinal cord of a tadpole : Exploring different ways to model
  the spinal cord in the Xenopus frog'
type: dissertation
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
year: '2025'
...