New research from 91亚色's Faculty of Graduate Studies sheds light on how the brain adjusts during movement with findings that could inform how people relearn skills, including in rehabilitation settings.
Everyday actions such as reaching for a cup or typing on a keyboard, rely on constant feed back from the brain. It monitors how each movement was executed and makes small refinements as needed. If a hand lands slightly off target, for example, that error is used to improve the next attempt.
Researchers distinguish between two ways the brain's neural activity updates these movements. Sometimes it fine鈥憈unes an existing skill, making small, automatic adjustments 鈥 like when a baseball pitcher corrects their aim after a missed throw. Other times, it must develop a new way of moving altogether, especially when familiar patterns no longer work, such as when moving a computer mouse with your hand one way makes the on-screen cursor move in the opposite direction.
Research led by PhD candidate Raphael Gastrock, supervised by Professor Denise Henriques and research associate Bernard Marius 鈥檛鈥疕art, examines what happens in neural systems when the brain responds to these two forms of learning. Published in , the study compares how the brain responds to errors when refining an existing skill (motor adaptation) versus learning a new one (de novo learning).
鈥淲e wanted to explore how the brain processes errors across these two forms of learning,鈥 Gastrock says. 鈥淎lthough previous research has identified brain signals linked to adapting movements, no studies have directly compared those signals between adaptation and acquiring a completely new way of moving. With this work, we aimed to address that gap.鈥
To test this, participants completed simple "reaching" tasks using a stylus to move a cursor toward a target on a screen. After establishing how participants moved under normal conditions, researchers altered the visual feedback to compare the two types of learning.
In one case, the cursor was slightly rotated, requiring participants to adjust their aim, representing 鈥渁daptation鈥 learning, where neural systems gradually tweak an existing motion. The other scenario flipped the display like a mirror, meaning left and right were reversed, presenting the more demanding "type of skill "de novo" learning, where the brain creates a new plan to adapt to the movement.
Researchers recorded neural activity using electroencephalography, or EEG, to track how the brain prepared each movement and how it responded after participants saw the result. They found when participants adjusted to the rotated display, their neural activity changed as they improved, suggesting the brain gradually learns how to correct the action. As their aim got better, their responses to errors also became smaller, showing the task was becoming more predictable.
The mirror reversal showed a different pattern, however. Although participants movements improved, their neural activity changed very little, suggesting they had to actively think through each motion instead of relying on automatic adjustments.
Together, the findings point to a simple idea: the brain uses different approaches depending on the kind of problem it faces. When errors are consistent and predictable, it can fine鈥憈une movements automatically; however, when the task requires a new set of rules, it depends more on deliberate, effortful strategies.
This distinction may help explain why some skills are easier to learn 鈥 or relearn 鈥 than others.
鈥淢otor learning plays a central role in everyday activities, from acquiring new skills to recovering function after injury,鈥 Gastrock says. That recovery process is one area where the team鈥檚 findings could have real鈥憌orld impact.
The findings could be especially relevant for physical rehabilitation, where repeated practice and feedback are used to help people regain movement. Understanding when the brain can refine automatically versus when it requires more more cognitively demanding and effortful adaptation, could help design more effective programs.
鈥淏y better understanding the mechanisms behind it, we may be able to improve training and rehabilitation strategies,鈥 he adds.
The researchers describe the work as an early step, but one that helps clarify how the brain handles different kinds of learning 鈥 and area that has been rarely examined side by side. The dataset has also been made publicly available to support further research.
By showing that human鈥檚 neural systems use distinct processes to fine鈥憈une actions or build new ones, the study offers a clearer framework for understanding how people gain and regain skills.
鈥淚n the long term, I hope findings from these types of studies can help inform rehabilitation approaches, educational strategies and skill training,鈥 Gastrock says.