My area of research is respiratory physiology and neurobiology. My research program examines respiratory control systems with particular emphasis on how the brain produces discontinuous breathing patterns (e.g. , episodic breathing) and how central (brain) and peripheral (arterial; lung) control systems are altered by long-term exposure to low oxygen or high carbon dioxide levels.
Research Area: Respiratory Physiology and Neurobiology; Comparative Physiology
Currently my research is focused on three main areas: 1) how the brain produces discontinuous patterns of breathing in amphibians and how respiratory control systems in these animals are altered by chronic hypoxia and hypercapnia. We are examining regions in the midbrain that likely communicate with respiratory control regions in the medulla oblongata to convert a continuous breathing pattern into a discontinuous, or episodic pattern. This work examines specific regions and the specific neurotransmission that occurs within these regions. We are investigating how central pH/CO2 chemoreceptor function is altered by exposure to chronic hypoxia and chronic hypercapnia as well as the role of altered afferent input from arterial oxygen chemoreceptors, olfactory CO2 receptors and lung stretch receptors on central CO2 chemoreceptor function. These studies use an isolated brainstem-spinal cord preparation from amphibians such as cane toads or leopard frogs. The brainstem-spinal cord is superfused in vitro with artificial cerebral spinal fluid and motor output from respiratory-related nerves serves as an index of breathing. 2) how exposure to chronic hypoxia alters breathing in mammals (rats) and how changes in glutamate and GABA neurotransmission within the brain produce these alterations in breathing. These studies measure breathing in rats using plethysmography with and without pharmacological manipulation to alter respiratory control systems that may change during chronic hypoxia.