Our research program aims to study the neuronal mechanisms involved in the control of locomotion. Our work spans a broad range of populations, from patient models of neurodegeneration extending to elite sport performance modeling superior function and integrates types of methodology such as non-invasive brain stimulation, brain imaging, and motion sensors to better understand how balance and gait are controlled and to develop innovative evidence-based interventions for gait impairments.

Study Populations

Parkinson’s disease is a neurodegenerative disease that causes a variety of motor and non-motor symptoms. In the HBCL lab, our focus is to identify the neural causes of gait impairments and how they can be targeted for rehabilitative interventions aimed at improving mobility and at the same time, quality of life. Better understanding how non-motor symptoms of this disease, such as fatigue, interact with locomotor symptoms is also part of our research program. Furthermore, we are involved in a CIHR-funded clinical trial investigating which type of exercise modality can better improve sleep in individuals living with Parkinson’s disease.

• Potvin-Desrochers et al. Upregulation of the parietal cortex improves freezing of gait in Parkinson's disease. 2023, J Neurol Sci. doi: 10.1016/j.jns.2023.120770.
• Potvin-Desrochers et al. Levodopa alters resting-state functional connectivity more selectively in Parkinson's disease with freezing of gait. 2023 Eur J Neurosci. doi: 10.1111/ejn.15849.
• Cristini et al. The Effect of Different Types of Exercise on Sleep Quality and Architecture in Parkinson Disease: A Single-Blinded Randomized Clinical Trial Protocol. 2023, Phys Ther. doi:10.1093/ptj/pzad073.
• Mitchell et al. Cerebral metabolic changes in Parkinson’s disease with freezing of gait during complex walking. 2018 J Nucl Med. doi: 10.2967/jnumed.118.218248
• Mitchell et al. Gait and trunk kinematics during prolonged turning in Parkinson's disease with freezing of gait. 2019 Park & Rel Disord doi: 10.1016/j.parkreldis.2019.04.011.

Research work is also achieved with older adults. Specifically, we try to identify how aging impacts the neural control of balance and gait with the goal of contributing to the development of preventive programs to compensate for declines in posture and mobility.

• Conradsson et al. The effects of dual-tasking on temporal gait adaptation and de-adaptation to the split-belt treadmill in older adults. 2019 Exp Geront doi: 10.1016/j.exger.2019.110655.
• Mitchell et al. Impaired sensorimotor processing during complex gait precedes behavioral changes in middle-aged adults. 2018 J of Geront: Biol Sci doi: 10.1093/gerona/gly210.

The HBCL lab also contributes to sports science research by studying the involvement of the central nervous system in sports performance of elite athletes. We also aim to identify neuroplastic hallmarks of exercise throughout the lifespan, from young elite runners to masters’ athletes.

• Potvin-Desrochers et al. Resting-state functional connectivity of the motor and cognitive areas is preserved in masters athletes. Under revision in Neuroscience.
• Fernandes et al. Increasing brain excitability of prefrontal and motor areas enhances time-trial performance in endurance runners. Presentation at Minds in motion, McGill University, 2023.
• Lajeunesse et al. Investigating the Effects of iTBS on Cortical Excitability in Endurance Runners. Poster at Canadian Association for Neuroscience, Canada, 2023.
• Sierra et al. Sex Differences of Increased Excitability of the Prefrontal and Motor Cortex to Improve Performance. Poster at Organization for Human Brain Mapping, Montréal, 2023

We also conduct research in healthy young adults to identify brain structures and neuronal networks directly involved in the control of posture, locomotion and steering of human locomotion. This work is paramount as it acts as a first step towards its application to clinical populations.

• Parent-L’Ecuyer. Mapping and quantifying the excitability of a bilateral cortical representation of the tibialis anterior muscles: a TMS study. MSc Thesis, McGill University, 2023.
• Hinton et al. Does dual-task placement and duration affect split-belt treadmill adaptation? 2020 Gait Posture. doi: 10.1016/j.gaitpost.2019.10.005.
• Hinton et al. Everyday multitasking habits: University students seamlessly text and walk on a split-belt treadmill. 2018 Gait Posture. doi: 10.1016/j.gaitpost.2017.10.011.

Methodology

HBCL lab has expertise in different types of brain imaging techniques. Its location beside the world-renowned Montreal Neurological Institute (MNI) makes it a place of choice to conduct neuroimaging studies. We have been using structural and functional MRI to identify neuroplastic changes associated with the practice of high-level sports and Parkinson’s disease at rest. We also use a full brain imaging approach to quantify brain activation changes DURING real walking: 18F-fluorodesoxy-glucose Positron Emission Tomography (18F-FDG PET) imaging.

The laboratory is also fully equipped with a neuro-navigated transcranial magnetic stimulation (TMS) system that allows us to conduct studies assessing and/or modulating the cortical excitability of upper and lower limbs. We use single-coil and dual-coil protocols to directly study brain networks and their alterations in clinical populations. TMS is also used in his repetitive form (rTMS) to modulate specific brain regions for sports performance or to alleviate symptoms of Parkinson’s disease, for example. A wide variety of coils (i.e., figure-of-eight ranging from 25 to 70-mm, dome, double cone) is available in the lab to ensure an optimal stimulation of each brain region.

Locomotion behavior can also be directly studied in unconstrained environments using wearable inertial measurements units (IMU). Different gait parameters can be quantified, thus allowing to determine the impact of Parkinson’s disease on gait performance and to detect specific gait impairments. The IMU can also be used to study body movement during sports performance. When combined with brain imaging or TMS techniques, IMU can further complement the modeling of neuroplastic changes associated with locomotion.

Locomotor adaptation can be studied in HBCL lab using a split-belt treadmill. This type of treadmill allows the feet to be driven at different speeds by independently controlled treadmill belts. When combined with other methodologies, such as 18F-FDG PET imaging or inertial measurements units (IMU), the use of the split-belt treadmill can help identify mechanisms involved in locomotor adaptation.

Funding