Northwestern Events Calendar

Apr
24
2017

PTHMS Special Seminar: Alain Frigon, PhD

When: Monday, April 24, 2017
12:00 PM - 1:00 PM CT

Where: 645 N. Michigan Avenue, Room 800, Chicago, IL 60611 map it

Audience: Faculty/Staff - Student - Public - Post Docs/Docs - Graduate Students

Contact: Erin Neal  

Group: PTHMS

Category: Lectures & Meetings

Description:

Alain Frigon, PhD
Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Sherbrooke, Quebec
“The control of left-right coordination and speed by spinal locomotor circuits” MONDAY, APRIL 24, 2017
12:10-1:00
RM. 800 645 N. MICHIGAN

Abstract:   The basic locomotor pattern is generated by a network of neurons within the spinal cord called a central pattern generator (CPG). It is thought that each hindlimb is controlled by its own spinal locomotor CPG and that left-right coordination is mediated by commissural interneurons. To investigate the control of left-right coordination by spinal circuits interacting with somatosensory feedback, adult cats were spinal-transected at low thoracic levels and trained to recover hindlimb locomotion. Cats were implanted with electrodes to record muscle activity (EMG, electromyography) and to stimulate peripheral nerves to evoke reflexes. After stable hindlimb locomotion recovered, cats performed tied-belt (equal left-right speeds) and split-belt (unequal left-right speeds) locomotion. The results show that cutaneous reflexes are modulated non-linearly with speed during tied-belt locomotion. Moreover, during split-belt locomotion, cutaneous reflex amplitude is smaller than what would be predicted based on belt speed. We propose that the spinal locomotor network modulates somatosensory feedback to optimize dynamic stability when changing speed and when left-right coordination is challenged.  

Bio:   I have a broad background in neuroscience and kinesiology, with specific expertise in spinal cord neurophysiology and locomotor control. For the past 15 years, my research has focused on the neural control of rhythmic movements (arm cycling, locomotion and scratching) and on neurophysiological and biomechanical changes that take place after spinal cord or peripheral nerve injuries. I have research experience with human subjects and the cat model. I received experimental training with the cat model in three different laboratories that used different preparations including in vivo recordings in awake behaving cats (Serge Rossignol), intracellular/extracellular recordings in curarized decerebrate cats (Jean-Pierre Gossard) and electromyography and force recordings in immobilized decerebrate cats (Charles J. Heckman). I currently use or have used a wide range of experimental techniques to study the control of movement in the cat. My lab has developed a unique approach to study the neural and biomechanical control of interlimb coordination during locomotion using a treadmill with four independent running surfaces. With this treadmill, the speed of the left and right sides (left-right split-belt) or of the forelimbs and hindlimbs (transverse split-belt) can be independently controlled in intact or spinal cord-injured cats. This allows the control of interlimb coordination to be systematically challenged and studied before and after injury. To investigate neural and biomechanical control mechanisms, split-belt locomotion is combined with lesions (spinal cord, peripheral nerves), chronic implantations for electromyography or nerve stimulation and 3D motion capture.

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