Summary: Researchers found that visual aids creating illusions of movement, like screens showing a hands motion, can enhance motor performance and early-stage motor learning. Functional near-infrared spectroscopy revealed distinct brain activity changes in motor learning regions compared to traditional third-person motion observation. These findings may have implications for innovative treatments for hemiplegic stroke patients.

Key Facts:

Source: Tokyo Metropolitan University

Researchers from Tokyo Metropolitan University showed that visual aids which create the illusion of movement, like a screen placed in front of ones hand showing the hand move, can improve motor performance and the early stages of motor learning.

Compared to observing third-person motions, functional near-infrared spectroscopy data also showed greater changes in brain activity in regions associated with motor learning. Findings like this might inform new treatment strategies for hemiplegic stroke patients.

Visual-motor illusion (VMI) is the curious illusion of watching your body move even while it is still. Imagine having a tablet screen placed in front of your hand. Your hand is hidden behind the tablet, and your hand is not moving. Now, imagine the screen playing a video of your hand moving; your eyes are telling you that your hand is moving, but it is not moving at all.

This unsettling situation is instantly resolved if you put the screen somewhere else; watching the screen now simply entails action observation (AO). Previous work has already shown that VMI and AO entail different responses in the brain, but the wider implications of VMI remained unclear.

Now, a team of scientists led by Assistant Professor Katsuya Sakai from Tokyo Metropolitan University have shown that VMI can improve motor performance and early-stage motor learning. Volunteers were set a specific task, rolling two metal ball around in one hand. After some initial testing, a visual aid was used which showed hands performing this exact action.

One group had the visual aid placed in front of their hand to invoke VMI, while another group simply watched the same video normally. Performance could be measured by the number of complete rolls that people managed.

Though both groups showed improvement, the VMI group showed more improvement than the AO group, both immediately after the video was shown to volunteers, and one hour afterwards. This not only shows improvement in performance but highlights that early-stage learning has also improved i.e. the changes can persist.

To understand what is happening in the brain, the team used functional near-infrared spectroscopy, a non-invasive technique that helps track activity in specific parts of the brain using external probes. They were able to find key differences between AO and VMI volunteers in parts of the brain associated with learning new movements.

Importantly, these changes were found to persist an hour after the visual stimuli, matching what they found from performance on the task. This was also in line with previous findings from the group showing how connectivity in parts of the brain responsible for motor execution was enhanced by VMI.

The team note that there is still a lot of work to be done. For example, these findings come from a study on healthy individuals, and there is yet to be any assessment of mid to long-term motor performance.

However, the insights gleaned from this study shed light on a unique strategy to improve motor performance and learning, which may one day be applied to the rehabilitation of hemiplegic stroke patients and guide the development of new treatments.

Funding: This work was supported by JSPS KAKENHI Grant Number 22K17569.

Author: GO TOTSUKAWA Source: Tokyo Metropolitan University Contact: GO TOTSUKAWA Tokyo Metropolitan University Image: The image is credited to Neuroscience News

Original Research: Open access. Differences in the early stages of motor learning between visualmotor illusion and action observation by Katsuya Sakai et al. Scientific Reports

Abstract

Differences in the early stages of motor learning between visualmotor illusion and action observation

The visual-motor illusion (VMI) induces a kinesthetic illusion by watching ones physically-moving video while the body is at rest. It remains unclear whether the early stages (immediately to one hour later) of motor learning are promoted by VMI. This study investigated whether VMI changes the early stages of motor learning in healthy individuals.

Thirty-six participants were randomly assigned to two groups: the VMI or action observation condition. Each condition was performed with the left hand for 20min.

The VMI condition induced a kinesthetic illusion by watching ones ball-rotation task video. The action observation condition involved watching the same video as the VMI condition but did not induce a kinesthetic illusion. The ball-rotation task and brain activity during the task were measured pre, post1 (immediately), and post2 (after 1h) in both conditions, and brain activity was measured using functional near-infrared spectroscopy.

The rate of the ball-rotation task improved significantly at post1 and post2 in the VMI condition than in the actionobservation condition. VMI condition lowers left dorsolateral prefrontal cortex and right premotor area activity from post1 to pre compared to the actionobservation condition. In conclusion, VMI effectively aids early stages ofmotor learning in healthy individuals.

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Enhancing Motor Learning with Visual-Motor Illusions - Neuroscience News