NEUROPHYSIOLOGY

Neurophysiology research in the Department of Physiology at MCW is closely linked to respiratory physiology research. It is centered on understanding the neural mechanisms involved in the control of breathing at various stages of maturity and in response to various environmental and physical stressors. Other projects focus on stroke and the reduction of the neural deficits resulting from it.

Maturation of the ventilatory control system takes place following birth, although the factors influencing this maturation remain under investigation. Studies use different animal models to gain insight into the time-course of normal development of the ventilatory control system, as well as the effect of environmental and genetic influences on these changes during development.  A newborn piglet model is currently being used to determine whether a critical window of development exists in the ventilatory control system that has been proposed as a part of a triple-risk model in Sudden Infant Death Syndrome. In addition, the interaction of plasticity and genetic influences is being studied using inbred strains of rats exposed to perinatal hyperoxia. In combination, these studies are aimed at understanding how the ventilatory control system matures under both normal and stressed conditions.

Research is also directed toward elucidating mechanisms that regulate breathing in adults. Breathing, respiratory muscle activity, heart rate and arterial blood pressure are continuously measured in all studies, which are completed in awake or asleep states. These studies provide insights into mechanisms of respiratory rhythm and pattern generation and intracranial chemoreception during normal conditions, during exercise, or when O 2 and CO 2 levels change in the brain. All these studies relate to disease conditions of central and obstructive sleep apnea, Sudden Infant Death syndrome, congenital central alveolar hypoventilation, and traumatic brainstem injury.

In addition, the department has an interest in understanding and quantifying the neural deficits caused by stroke and determining factors that can either protect the brain against ischemic damage or enhance recovery following cerebrovascular accident. Certain hormones and pharmaceutical agents have been shown to enhance brain capillary growth and also reduce the extent of infarction resulting from exposure of the brain to ischemia. Research efforts are underway to elucidate the mechanisms of the capillary growth as well as of the stroke-protection.