Real-time intracortical decoding from human motor cortex reveals a task-independent commitment to act that aligns with conscious intent

Neural signals within the brain's motor cortex that occur before a movement begins have been identified for some time. However, the true meaning behind these signals - whether they indicate a commitment to act, align with conscious intention, or can be controlled voluntarily - remains a matter of ongoing discussion.

To shed light on this topic, researchers conducted a closed-loop experiment featuring a strategic timing game. In this game, a virtual opponent observed participants' intracortical sensorimotor activity and intervened when their intention to move was detected. This experiment involved three individuals with tetraplegia who still had control over their wrist extension muscles.

The study found that movement onset could be reliably predicted from signals in motor cortex 250-400 milliseconds before the actual action took place. Despite participants' efforts to act unpredictably, they were preempted 94% of the time. Even when the opponent interrupted their actions, the intended movement generally followed through.

Interestingly, participants reported intending to act on 88% of the instances where they were preempted. Furthermore, the same decoding method used to predict movements during the competitive task accurately predicted participants' actions in a non-competitive scenario, without the need for retraining.

These findings demonstrate that late, task-independent motor-cortical states serve as a marker for a voluntary commitment to act. Participants' reports of intention align with these neural signals, even when disrupted by external factors.