David A. McCrea, Ph.D.

Professor Emeritus, Physiology & Pathophysiology

University of Manitoba

409 BMSB
My research focussed on understanding spinal cord motor systems organization to produce purposeful movements. This research is still being carried out in the SCRC by Dr. Katinka Stecina and others. Fictive locomotion is a rhythmic and coordinated activity of limb motoneurons similar to that occurring during normal overground locomotion. We use fictive locomotion to examine the activity of identified spinal interneurons with a focus on the identification of new types of spinal neurons. We wish to determine the connections between neurons, their activity during fictive locomotion and the neurotransmitters used. Peripheral nerve stimulation is used to perturb the locomotor cycle and examine how interneurons in spinal reflex pathways operate in conjunction with locomotor circuitry to adapt the locomotor pattern to a changing environment. Techniques include intracellular and extracellular recording from spinal interneurons and motoneurons, intracellular staining and anatomical reconstruction, analysis of cellular membrane properties, and analysis of the locomotor step cycle. Interneuron identification also involves simultaneous recordings from the interneuron and the neuron on which it makes synaptic contact. These experiments use combinations of dual microelectrode recordings, sucrose gap electrodes, and spike train or field potential analysis. Electrophysiological experiments on neurotransmitter systems use iontophoretic or pressure ejection of drugs with simultaneous extra or intracellular recording from neurons.
Areas of Expertise
Spinal cord electrophysiology, spinal motor circuitry, pre- and postsynaptic control mechanisms.
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See Also
Dept. of Physiology & Pathophysiology profile for Dr. McCrea