Grant: Doctoral Award - Frederick Banting and Charles Best Canada Graduate Scholarships

Following a spinal cord transection, it has been shown in cat and rat the application of the neuromodulator serotonin (5-HT) can restore locomotor-like behaviour. This locomotor-like behaviour is characterized by the alternating muscle activity between the flexor muscles and extensor muscles. The restoration in locomotor-like behaviour occurs at least in part by 5-HT activating channels in the spinal network that increases the excitation of spinal motoneurons, ultimately causing muscle to contract. Evidence has suggested that a potential difference in extensor motoneurons (neurons that cause extensor muscles to contract) and flexor motoneurons (neurons that cause flexor muscles to contract) to activate these channels exist - favoring the extensor motoneurons. Furthermore, after a spinal cord injury, spasticity is generally seen in extensor muscles but not flexor muscles and spasticity is thought to occur by an increase in sensitivity to 5-HT. Combined, this suggests that differences exist in sensitivity to 5-HT between extensor and flexor motoneurons. The purpose of my PhD will be to examine which motoneurons properties 5-HT alters in a normal state and a period of inactivity. As well to examine if there are differences in how 5-HT modulates extensor and flexor motoneuron properties and to compare the potential differences in the number of channels and receptors on the motoneurons that 5-HT is known to activate. This research is significant because it will provide insight into how motoneurons are modulated by 5-HT in different activity levels. As well, it will provide important information about differences in extensor and flexor motoneurons for the purpose of therapeutic and pharmacological interventions aimed at restoring walking after a spinal cord injury.