Control of breathing in vertebrates

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Research in my lab examines the evolutionary origins of respiratory processes and the adaptive changes in these processes that allow animals to exploit diverse environments. As such it contributes to our understanding of the mechanistic basis of biodiversity and the physiological costs of habitat selection. Within this context we examine respiratory and cardiovascular adaptations in vertebrate animals under various conditions (at rest, sleep, exercise, altitude, dormancy, hibernation, diving, etc.). Breathing is essential for providing oxygen and removing carbon dioxide from tissues in all large, multi-cellular organisms. Certain areas within the brain of all vertebrates (from fish to man) produce a respiratory rhythm but this rhythm is not always expressed. This natural rhythm is modified by information from different sensory systems and from other areas in the brain that determine if, when and how breathing occurs. This leads to the hypothesis that the wide variety of breathing patterns and ventilatory responses observed in vertebrate animals result from differences in the net balance of inputs to a common system, and from differences in the sensitivity of the various components of the system. There are many breathing patterns seen in vertebrates, including those that contain prolonged periods during which breathing ceases (apneas etc.). These breathing patterns not only challenge this hypothesis, they also suggest that a mechanism that can explain the episodes where breathing stops in turtles and hibernating squirrels may also explain episodic breathing in carp and sleep apnea in man. Using species differences (phylogeny), developmental changes (ontogeny) and genetic manipulations as tools, we hope to determine the sites and neural basis of respiratory rhythm and pattern formation (fundamental mechanisms). We also hope to determine the manner in which cardiovascular and respiratory responses can be modified in the short term (acclimation) and have been shaped by evolution in the long term (adaptation) to meet the demands of vertebrate animals living in diverse habitats.