Attempted vs imagined movement decoding

In intracortical motor BCI, participants are typically instructed to attempt a movement — to actually try to move the paralyzed limb or hand — rather than merely to imagine it. Attempted movement recruits the motor-cortical machinery for action execution and tends to evoke stronger, more consistent, and more spatially structured population activity than pure motor imagery, which is closer to a covert planning or observation state. For people with paralysis whose descending pathways are interrupted but whose cortex is intact, the attempt produces robust cortical output even though no overt movement results.

The distinction is practical and consequential. Attempted-movement strategies generally yield better decoding, and the instruction itself (attempt writing, attempt reaching, attempt speaking) shapes which cortical patterns appear and thus what a decoder can learn. This connects motor BCI to the imagined-versus-attempted-speech question in speech neuroprostheses, where the same choice strongly affects signal quality. The residual attempt-related activity in chronically paralyzed cortex is a large part of why intracortical BCI is feasible at all.