UBC Theses and Dissertations
Locomotor-respiratory synchrony in the Canada goose Funk, Gregory Douglas
Using a variety of preparations, (intact birds during treadmill and overground walking/running and free-flight; decerebrate birds during electrically induced walking/running, passive wing flapping, and electrically induced wing flapping and "Active" flight), this thesis examines some of the mechanisms involved in the production and control of locomotor-respiratory coordination (entrainment) during alternating hindlimb locomotion (walking/running) and synchronous forelimb locomotion ("flight") in the Canada goose. Significant coordination of locomotor and respiratory rhythms was observed during both modes of locomotion in intact as well as decerebrate birds. While coordination of forelimb motion and respiration was virtually complete, coordination of hindlimb motion and respiration was sporadic. The level of entrainment during hindlimb locomotion, however, increased with increased stride frequency, rather than increased work rate, suggesting that proprioceptive feedback from the limbs is involved in the production of locomotor-respiratory entrainment. Further evidence for a role of proprioceptive feedback in the production of entrainment was provided by the entrainment of respiration by passive wing motion in decerebrate geese. Although feedback from the periphery was sufficient for the entrainment of wing motion and respiration, motor nerve outputs to the wing and respiratory musculature were also synchronized in paralyzed, decerebrate birds during electrically induced activity, in the complete absence of phasic afferent feedback. Thus, both feedback and feedforward mechanisms appear sufficient for the coordination of wing beat and respiration.