The overall goal of the Sensorimotor Neuroscience Lab is to determine how the brain acquires, deals with changes in the quality of, and uses visual information to control and adapt walking (and movement in general). Essentially, we try to understand how the brain uses what it sees to move.
The following describes our three primary research themes:
How People Make Decisions About Where to Look and Where to Walk
Consider walking through a crowded sidewalk or shopping mall, or hiking through the cluttered terrain of a forest. Visual information about the world helps people make good decisions as to where to move in these situations. The brain shifts gaze to points of interest to acquire this visual information. And it must incorporate what it sees with its expectations and current goals. Our research in this area poses two questions: (1) What factors influence the decision of where, when, and for how long to allocate gaze for guiding movement? (2) What are the visual perceptual and cognitive factors that influence collision avoidance behaviour?
Select Related Publications:
- da Eira Silva V, Marigold DS. Fork in the road: how self-confidence about terrain influences gaze behaviour and path choice. https://www.biorxiv.org/content/10.1101/2023.06.29.547105v2.
- Domínguez-Zamora FJ, Marigold DS. Motives driving gaze and walking decisions. Curr Biol 31: 1632-1642, 2021.
- Domínguez-Zamora FJ, Lajoie K, Miller AB, Marigold DS. Age-related changes in gaze sampling strategies during obstacle navigation. Gait Posture 76: 252-258, 2020.
- Domínguez-Zamora FJ, Marigold DS. Motor cost affects the decision of when to shift gaze for guiding movement. J Neurophysiol 122: 378-388, 2019.
- Domínguez-Zamora FJ, Gunn SM, Marigold DS. Adaptive gaze strategies to reduce environmental uncertainty during a sequential visuomotor behaviour. Sci Rep 8: 14112, 2018.
How the Brain Adapts to Movement Errors: Visuomotor Learning
The ability to adapt to our surroundings and retain what is learned is essential for survival and performing many daily activities. When moving, however, we must contend with the effects of aging, injury, disease, and an ever-changing environment. These effects can change the normal relationship (or mapping) between sensory input and motor output, thus causing errors in movement. Experience suggests we can learn and retain new mappings. For instance, we can quickly determine how to control a cursor on a screen using a mouse or trackpad. We can also transfer (or generalize) mappings to new situations; for example, this can allow us to switch between different tablets or cell phones.
We study these processes, usually in the context of walking, by systematically exposing the brain to perturbations that shift the visual field. This technique artificially alters the visuomotor mapping, resulting in a mismatch between the expected and actual outcome of a movement. Over time, individuals adapt to this change in mapping and become more accurate. Our research is focused on identifying factors that enhance how we learn, retain, and transfer these mappings. This insight may assist in the development of more effective rehabilitation strategies.
Select Related Publications:
- Bakkum A, Marigold DS. Learning from the physical consequences of our actions improves motor memory. eNeuro 9: ENEURO.0459-21.2022, 2022.
- Bakkum A, Donelan JM, Marigold DS. Savings in sensorimotor learning during balance-challenged walking but not reaching. J Neurophysiol 125: 2384-2396, 2021.
- Bakkum A, Donelan JM, Marigold DS. Challenging balance during sensorimotor adaptation increases generalization. J Neurophysiol 123: 1342-1354, 2020.
- Maeda RS, McGee SE, Marigold DS. Long-term retention and reconsolidation of a visuomotor memory. Neurobiol Learn Mem 155: 313-321, 2018.
- Maeda RS, O'Connor SM, Donelan JM, Marigold DS. Foot placement relies on state estimation during visually guided walking. J Neurophysiol 117: 480-491, 2017.
How Visual Impairment Affects Gaze and Mobility
The inability to properly see makes activities of daily living difficult to perform. Decreased quality of vision, which affects hundreds of millions of people worldwide, increases the risk of colliding with objects, tripping, falling, and the likelihood of injury. As a consequence of poor vision, people change the way they look at, or visually sample, the environment. This can prevent the formation of an accurate representation of their surroundings, such as the location of objects. Because when and where a person looks is tightly related to limb movement, this also disrupts how vision guides goal-directed actions. For instance, one must direct gaze to a sidewalk curb at the correct time and for sufficient duration to decide when and how high to step.
In one aspect of our research, we study how older adults with glaucoma navigate around obstacles and step precisely onto certain locations on the ground. We have found that when and where these individuals look during these tasks relates to greater object collisions and reduced foot-placement accuracy. This suggests that these individuals are using their remaining visual function ineffectively, which provides an avenue for intervention. Gaze training may improve mobility in these individuals.
Select Related Publications:
- Gunn SM, Lajoie K, Zebehazy KT, Strath RA, Neima DR, Marigold DS. Mobility-related gaze training in individuals with glaucoma: a proof-of-concept study. Transl Vis Sci Technol 8(5):23, 2019.
- Lajoie K, Miller AB, Strath RA, Neima DR, Marigold DS. Glaucoma-related differences in gaze behavior when negotiating obstacles. Transl Vis Sci Technol 7(4):10, 2018.
- Miller AB, Lajoie K, Strath RA, Neima DR, Marigold DS. Coordination of gaze behavior and foot placement during walking in persons with glaucoma. J Glaucoma 27: 55-63, 2018.
- Alexander MS, Lajoie K, Neima DR, Strath RA, Robinovitch SN, Marigold DS. Effects of macular degeneration and ambient light on curb negotiation. Optom Vis Sci 91: 975-989, 2014.
- Alexander MS, Lajoie K, Neima DR, Strath RA, Robinovitch SN, Marigold DS. Effect of ambient light and macular degeneration on precision walking. Optom Vis Sci 91: 990-999, 2014.
Other Research Interests
How non-visual sensory input is integrated with normal or degraded vision during walking
The role of the posterior parietal cortex in visually guided movement
Current and/or Past Research Funding
Natural Sciences and Engineering Research Council of Canada (NSERC)
Glaucoma Research Society of Canada
Canadian National Institute for the Blind (CNIB)
Simon Fraser University - Office of the VPR