In a groundbreaking advance at the intersection of neuroscience and brain-machine interfaces, researchers led by Jean-Paul Noel at the University of Minnesota have elucidated the intricacies of how the human brain links intention to action in real time. Published on April 17, 2025, in the open-access journal PLOS Biology, their study reveals profound insights into the phenomenon of temporal binding between intention and action — a cognitive process that causes intentional movements to be perceived as occurring faster than their actual duration. This pivotal finding was made possible by an ingenious experimental design that separated the components of voluntary movement—intention, action, and sensory effect—using cutting-edge neurotechnology in a participant with paralysis.
The experimental subject, a man with tetraplegia caused by damage to his C4/C5 vertebrae, was implanted with a microelectrode array of 96 electrodes positioned over the hand region of his primary motor cortex. This unprecedented access to the human motor cortex afforded the research team a unique window on the neural correlates of intention on a single-neuron level—a level of precision typically unobtainable in humans. The brain-machine interface (BMI) utilized sophisticated machine learning algorithms to interpret the participant’s neural activity in real time, distinguishing between “squeeze” and “relax” signals, thereby translating these intents into electrical stimulations of hand muscles to effect movement.
Central to the findings was the measurement of perceived temporal intervals from intention to physical action. Through this brain-machine link, the participant was able to squeeze a ball, which produced an auditory cue. Remarkably, the participant consistently perceived the interval between his intent to move and the execution of the movement to be about 71 milliseconds shorter than the objective time recorded. This discrepancy points to a temporal compression effect, where the conscious experience of intention and consequent action converge more tightly in subjective time than in actual physiological sequence.
To dissect this perceptual phenomenon, the researchers strategically manipulated components of the movement chain. By delivering random electrical stimulations to induce hand squeezes without accompanying intention, the experiment effectively removed the subjective intent component. Under these conditions, the participant’s perception of when the action occurred shifted, with actions estimated to happen later than usual. Contrarily, when the participant attempted to generate an intention to squeeze but no actual movement ensued due to lack of muscle stimulation, the temporal perception of intention was altered if the sound cue remained. In such cases, the intention seemed to arise earlier in time, emphasizing the role of sensory feedback in anchoring temporal perception.
These observations illuminate the neural underpinnings of agency—the sensation that one is the creator of their own actions. Electrophysiological recordings revealed that neuronal firing rates in the primary motor cortex closely matched the participant’s subjective onset of movement intention, demonstrating co-occurrence between the neural signature and conscious experience. This coalescence challenges traditional views that locate the genesis of intention in frontal cortical areas alone, suggesting that the primary motor cortex also participates in representing volitional signals at the final cortical step before motor execution.
The study builds upon prior seminal work, such as that by Fried and colleagues (2011), which identified frontal cortical regions encoding intention up to a second before subjective awareness. While those studies provided valuable non-invasive insights and occasional single-neuron data, the current research extends understanding by interrogating the primary motor cortex, considered the last cortical waypoint before action reaches the spinal cord. This node’s involvement in the subjective experience of intention widens the scope of neural networks underlying volition and motor planning.
Technically, this research relied on the synergy of multiple disciplines including neurosurgery, neuroscience, neuroengineering, and machine learning, highlighting the collaborative nature required for such complex human experimentation. The precise implantation of electrodes demanded neurosurgical expertise, while algorithmic decoding of neural signals integrated advanced computational methods. By leveraging the capabilities of brain-machine interfaces, the team could achieve unprecedented separation of intention from action and its sensory consequences—something previously unfeasible in human participants.
The implications of these findings extend far beyond basic neuroscience. Understanding how the brain temporally binds intention to action with sensory feedback may shed light on disorders of agency and motor control seen in conditions like Parkinson’s disease, stroke, or schizophrenia. Moreover, the refined decoding of movement intentions from neural ensembles paves the way for improved brain-machine interfaces to restore motor functions in paralyzed individuals. By elucidating the fine temporal mechanics underlying volitional movement, this study brings science closer to real-world applications that could enhance human-machine integration.
The experimental paradigm’s elegance lies in its temporary dissociation of the normally inseparable components of voluntary movement. By independently manipulating intention (via attempted movement), action (via electrical stimulation), and outcome (via auditory feedback), the researchers could precisely chart how each element contributes to the conscious experience of agency. The finding that sensory feedback—in this case, the sound following a grip—modulates the subjective timing of intention reflects the brain’s integrative processing of multimodal signals to produce coherent conscious awareness.
Furthermore, the observed temporal binding phenomenon supports theories suggesting that volitional awareness and action are not strictly linear in time but can be subjectively compressed. The accelerated perception of intentional actions may functionally facilitate rapid interaction with the environment, optimizing sensorimotor responsiveness. Additionally, demonstrating that neural firing in the motor cortex aligns with the subjective timing of intention suggests that conscious volition emerges within widely distributed motor networks rather than relying solely on high-order cognitive regions.
This study sets an important precedent for the ethical use of invasive neural recordings in humans to probe fundamental questions about free will and conscious experience. With no competing interests declared and transparent funding disclosures, the multidisciplinary team including members from the United States, Switzerland, and the United Kingdom, underscores a global effort toward unraveling the neural basis of human agency. Supported by various foundations and fellowships, this research exemplifies the potential of combining clinical neurotechnology with basic neuroscience research.
The implications for the broader scientific and philosophical discourse are considerable. The debate surrounding free will—whether our intentions are genuinely generated by conscious volition or are predetermined by prior neural activity—receives fresh evidence that the primary motor cortex participates actively in the real-time subjective onset of intention. This challenges simplistic interpretations and urges a re-examination of how conscious experiences relate temporally and causally to brain processes.
As brain-machine interfaces evolve, the capacity to decode and respond to human intentions promises transformative applications in neuroprosthetics, rehabilitation, and augmented human capabilities. This study not only advances technical methodologies but also provides deeply human insights into how we perceive control over our actions. Such insights enrich both the scientific understanding of consciousness and the practical pursuit of restoring autonomy to individuals with motor disabilities.
In summary, through deft use of intracortical recordings, machine-learning decoding, and controlled sensory manipulations, Jean-Paul Noel and colleagues have revealed that the human primary motor cortex’s neuronal activity corresponds intimately with the instant we feel the urge to move. The temporal binding they documented compresses the timeframe between intention and action, highlighting a crucial aspect of how conscious will is experienced and enacted. This landmark research stands as a testament to the profound capabilities unlocked at the nexus of human neuroscience and advanced neuroengineering.
Subject of Research: People
Article Title: Neuronal responses in the human primary motor cortex coincide with the subjective onset of movement intention in brain–machine interface-mediated actions
News Publication Date: April 17, 2025
Web References:
http://dx.doi.org/10.1371/journal.pbio.3003118
References:
Noel J-P, Bockbrader M, Bertoni T, Colachis S, Solca M, Orepic P, et al. (2025) Neuronal responses in the human primary motor cortex coincide with the subjective onset of movement intention in brain–machine interface-mediated actions. PLoS Biol 23(4): e3003118.
Image Credits:
Noel J-P, et al., 2025, PLOS Biology, CC-BY 4.0
Keywords:
brain-machine interface, temporal binding, motor cortex, movement intention, neuroprosthetics, neural decoding, paralysis, volition, subjective experience, sensorimotor integration, neuroengineering, conscious will
Tags: brain-machine interfacescognitive processes in motor controlintention and action correlationmachine learning in neurosciencemicroelectrode array studiesmotor cortex explorationneuroscience researchneurotechnology in movementparalysis and brain researchsingle-neuron level analysistemporal binding in cognitionvoluntary movement neuroscience