motor imagery

What if the key to athletic performance and physical recovery wasn't just practice, but the ability to imagine movement itself? New research from Dr. William Dupont at the University of Grenoble Alps has uncovered a startling reality: people with aphantasia - the inability to form mental images - show fundamentally different brain responses when trying to imagine movement, potentially limiting their access to proven training and rehabilitation techniques.

The discovery challenges decades of sports psychology and physical therapy practices that rely heavily on "motor imagery" - the mental rehearsal of movements that has been shown to improve strength, coordination, and recovery from injury. For the estimated 1-4% of people with aphantasia, these widely used techniques may be essentially useless.

The Hidden World of Motor Simulations

Most of us take for granted a remarkable ability: we can imagine moving without actually moving. This "motor simulation" isn't just daydreaming about sports - it's a sophisticated brain process that activates the same neural networks involved in real movement.

"Motor simulations involve a mental representation of a movement and its sensory motor consequences without an actual production of movement," explains Dupont, a post-doctoral researcher whose work employs neuroimaging and neuropsychological methods to explore the relationships between motor systems and cognitive processes.

These simulations come in different forms. There's explicit motor imagery, where you deliberately imagine performing a movement, and implicit simulations that happen automatically when you watch someone else move or even read about movement. All of these processes, research has shown, can actually improve physical performance.

The Performance Enhancement Nobody Talks About

The power of motor imagery in improving athletic performance has been documented for decades. Studies show that athletes who spend weeks practicing mental rehearsal of movements can increase their muscle strength without ever lifting a weight.

"You can see here that kinesthetic motor imagery - imagining the muscle and articular sensation of movement - we can observe an increased motor performance," Dupont notes, referencing studies showing strength improvements following motor imagery training.

The effects extend beyond athletics. Stroke patients who practice motor imagery during rehabilitation recover faster and maintain better strength. Even reading action words like "grip" or "throw" can temporarily increase grip strength compared to reading abstract words.

But all of these benefits depend on one crucial assumption: that everyone can engage their motor systems through imagination.

The Brain Stimulation Breakthrough

To understand what happens in the brain during motor imagery, Dupont's team used transcranial magnetic stimulation (TMS) - a non-invasive technique that applies magnetic pulses to specific brain regions and measures the response in muscles.

"When stimulating the brain area controlling the right hand, we can record motor evoked potentials whose amplitude reflects the motor system excitability," he explains. This "corticospinal excitability" provides a direct measure of how activated the motor system becomes during different mental tasks.

Previous research had established a clear pattern: when people with typical imagery abilities imagine moving, watch others move, or read about movement, their motor systems show increased excitability - essentially "revving up" as if preparing for real movement.

The question Dupont wanted to answer was simple but profound:

"Are individuals with aphantasia able to activate the motor system during these processes? And if not, what does this imply for their ability to understand actions?"

The Aphantasia Motor Mystery

Dupont's team recruited 17 people with aphantasia and 17 with typical imagery abilities for a series of experiments. Participants first completed questionnaires measuring their ability to imagine movement and their tendency to use imagery in daily life.

The results confirmed what researchers expected: people with aphantasia reported severe impairment or complete inability to perform motor simulations and rarely used imagery in daily life.

But the brain stimulation results revealed something more surprising.

When asked to perform kinesthetic motor imagery - imagining the feeling of a pinching movement - people with typical imagery showed the expected increase in motor system excitability. People with aphantasia showed no change at all.

"We observed that phantasic participants increased the corticospinal excitability during kinesthetic motor imagery while aphantasic did not exhibit some modulation compared to the baseline," Dupont reports.

The same pattern emerged when participants watched videos of hand movements: typical imagers showed increased motor activation, while those with aphantasia remained at baseline levels.

The Reading Revelation

The second experiment extended the investigation to something even more fundamental: reading about movement.

When people read sentences like "John gripped the handle tightly," their motor systems typically activate automatically - an implicit simulation that helps with comprehension. This happens without any conscious effort to imagine movement.

But when Dupont's team measured brain responses during action reading, they found the same striking difference: people with typical imagery showed increased motor system excitability when reading about movement, while those with aphantasia showed no change.

Perhaps more concerning, this motor activation difference correlated with reading comprehension problems. While both groups performed equally well on basic reading tasks, people with aphantasia scored significantly lower on high-level comprehension questions that required making inferences about the text.

"Motor simulations and the absence of motor simulations can impact the reading comprehension in aphantasics," Dupont concludes.

The Kinesthetic Exception

One of the most intriguing findings involved the small number of people with aphantasia who could still perform kinesthetic (feeling-based) motor imagery, even though they couldn't visualize movements.

"Some individuals have multisensory aphantasia where kinesthetic motor imagery is impaired, and we can relate this subjective reports to the corticospinal excitability," Dupont explains. Those who retained kinesthetic abilities showed some motor system activation, while those with complete multisensory aphantasia showed none.

This suggests that different types of mental simulation - visual versus kinesthetic - rely on partially separate brain networks, and that the specific pattern of someone's imagery abilities determines their motor system responses.

The Athletic Implications

The findings raise profound questions about athletic training and rehabilitation for people with aphantasia. Mental rehearsal techniques are widely used across sports, from basketball free throws to tennis serves, with documented performance improvements.

"Between 1989 and 2022 there are several studies that demonstrated beneficial effects of motor imagery on motor training and sports training," Dupont notes, citing research showing improved basketball shooting and tennis performance following imagery training.

But if people with aphantasia can't activate their motor systems through imagery, do these techniques work for them at all?

When asked whether he'd be surprised to find athletes with aphantasia competing at elite levels, Dupont was diplomatic:

"I won't be surprised if aphantasics can be the highest athletes, better sportsmen in the world. It's just maybe they used some other strategies to be the best performers in the world."

The key question is what those alternative strategies might be, and whether traditional training methods are systematically excluding or disadvantaging athletes with aphantasia.

The Rehabilitation Crisis

Perhaps even more concerning are the implications for medical rehabilitation. Motor imagery is widely used in physical therapy, particularly for patients recovering from stroke, injury, or surgery.

"Recent studies show that combining action observation and motor imagery and performing five days per week is good for motor imagery training," Dupont explains, referring to standard rehabilitation protocols.

But these protocols assume patients can engage in motor imagery effectively. For people with aphantasia - who may not even realize they're different from other patients - these expensive and time-intensive treatments may provide little benefit.

"We don't have any data about aphantasics and motor rehabilitation," Dupont admits, highlighting a critical gap in medical knowledge that could be affecting millions of patients worldwide.

The Measurement Challenge

One practical challenge the research highlights is identifying who has different types of imagery abilities. While visual aphantasia is increasingly recognized, kinesthetic motor imagery is harder to assess and understand.

"It's really difficult for me also to imagine kinesthetic motor imagery," Dupont acknowledges. He describes it as trying to feel the muscular and joint sensations of movement without actually moving: "Try to feel this sensation as you make it, basically what would it feel like to move without actually moving."

This difficulty in explanation and measurement means that many people may be unaware they have different imagery abilities, particularly for non-visual senses like proprioception and kinesthesia.

The Brain Stimulation Solution

Looking forward, Dupont sees potential in neurostimulation techniques to help people with aphantasia engage their motor systems more effectively.

His research plan involves two steps: "First, brain investigation, and second, overcome these brain differences by stimulating the brain." The goal is to identify the specific neural networks that function differently in people with aphantasia, then use targeted brain stimulation to activate or enhance these systems.

"The purpose of such stimulation techniques is to overcome, compensate the brain differences, the hypoactivities, to see if we can help aphantasics for creating motor simulations," he explains.

This approach could potentially allow people with aphantasia to benefit from motor imagery training and rehabilitation techniques that are currently ineffective for them.

What This Means for Understanding Movement

Dupont's research reveals that the relationship between mind and body is more complex and variable than previously understood. The ability to mentally simulate movement - something most people assume everyone can do - turns out to be a specific neurological capacity that some people lack.

This has implications beyond athletics and rehabilitation. It suggests that fundamental aspects of how we understand and learn about movement, from reading action scenes in novels to following exercise instructions, may work differently for people with aphantasia.

The research also highlights the importance of recognizing neurological diversity in designing training programs, therapeutic interventions, and even educational materials. What works for the majority may be ineffective or inaccessible for significant minorities.

The Path Forward

As Dupont continues his research, several critical questions remain unanswered. Can neurostimulation actually help people with aphantasia engage in motor imagery? What alternative training methods work best for athletes and patients who can't use traditional imagery techniques? How many people are currently receiving ineffective treatment because their imagery differences haven't been recognized?

"How can we help aphantasics to create motor simulations? For us, this is the most important question," Dupont emphasizes. "Maybe it's not possible with our hypothesis, but we want to try."

The stakes are high. Motor imagery isn't just a performance enhancement technique - it's a fundamental tool for rehabilitation, learning, and human movement. Understanding how to make these tools work for everyone could transform approaches to athletic training, physical therapy, and motor skill development.

As research into aphantasia continues to reveal the hidden diversity of human consciousness, Dupont's work reminds us that even our most basic assumptions about how minds and bodies connect may need rethinking. The motor system, it turns out, is listening to the imagination - but not everyone's imagination speaks the same language.

Invisible Rehearsal: How Aphantasia Affects Motor Simulation and Rehabilitation