Showing 1 - 4 of 4 Items
The Regulatory Effect of High Dopamine on the Hyperpolarization-Activated Inward Current (Ih) and its Role in the Stability and Rhythmicity of Mammalian Locomotor Neural Networks Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2025-06-01
Date: 2022-01-01
Creator: Abigail Raymond
Access: Access restricted to the Bowdoin Community
Fall forward, spring back: Drivers of synchrony in the sea star crawl-bounce gait transition
Date: 2024-01-01
Creator: Brady R Nichols
Access: Open access
- The Froude number is the ratio of kinetic energy to gravitational potential energy used during locomotion and is often used to analyze gait transitions. Here, I compare and contrast the human walk-run gait transition, which occurs at a consistent Froude number of 1 because there exists a mechanical speed limit to walking, and the sea star crawl-bounce gait transition, which occurs around Froude numbers of 1*10^-3. In this thesis I investigate why sea stars exhibit two gaits despite lacking brains and moving at Froude numbers far below other known gait transitions, hypothesizing (1) that the crawl-bounce transition may be mechanical and thus still depends on the Froude number, and (2) that the crawl-bounce transition is best modeled gradually compared to the instantaneous human walk-run transition. Thirty sea stars were filmed and the resulting kinematic data is used here to inform thinking about the crawl-bounce transition. I first discuss damped driven harmonic motion of a single oscillator, but eventually turn to using coupled oscillators and deriving that a coupling constant between metronomes on a moving base is the Froude number, which is therefore relevant for the crawl-bounce transition. I lastly discuss a purely mathematical analogue of the crawl-bounce transition as a Hopf bifurcation in horizontal speed and vertical velocity phase space, which leads to a rough model with results qualitatively similar to observed kinematic data from films, and indicates that a gradual transition is in fact a good fit for the crawl-bounce transition.
The impact of temperature on the sea star oscillatory gait This record is embargoed.
- Embargo End Date: 2025-05-14
Date: 2020-01-01
Creator: Emma Victoria Bertke
Access: Embargoed
The modulation of calcium-activated potassium channels for the stabilization of mammalian spinal locomotor activity This record is embargoed.
- Embargo End Date: 2026-12-14
Date: 2023-01-01
Creator: Hattie Sargent Slayton
Access: Embargoed