  We and others have previously developed brain-machine-interfaces (BMIs),
which allowed ensembles of cortical neurons to control artificial limbs (1-4).
However, it is unclear whether cortical ensembles could operate a BMI for
whole-body navigation. Here we show that rhesus monkeys can learn to navigate a
robotic wheelchair while seated on top of it, and using their cortical activity
as the robot control signal. Two monkeys were chronically implanted with
multichannel electrode arrays which simultaneously sampled activity of roughly
150 premotor and sensorimotor cortex neurons per monkey. This neuronal ensemble
activity was transformed by a linear decoder into the robotic wheelchair's
translational and rotational velocities. During several weeks of training,
monkeys significantly improved their ability to navigate the wheelchair toward
the location of a food reward. The navigation was enacted by ensemble
modulations attuned to the whole-body displacements, and also to the distance
to the food location. These results demonstrate that intracranial BMIs could
restore whole-body mobility to severely paralyzed patients in the future.

Neurons and Cognition