Sense of agency for intracortical brain–machine interfaces

Abstract

Intracortical brain-machine interfaces decode motor commands from neural signals and translate them into actions, enabling movement for paralysed individuals. The subjective sense of agency associated with actions generated via intracortical brain-machine interfaces (BCI actions), the neural mechanisms involved and its clinical relevance are currently unknown, although the sense of agency for bodily actions of for example human hand actions has been deeply investigated.

By experimentally manipulating the coherence between decoded motor commands and sensory feedback in a tetraplegic individual using a brain-machine interface (with a brain implant in primary motor cortex, M1), we provide evidence that M1 processes sensory feedback signals, sensorimotor conflicts (between the intended action and visual and/or somatosensory feedback) and subjective states of actions for BCI actions (that is for actions generated via the brain-machine interface). Interestingly, neural signals associated with the subjective sense of agency or control over the BCI action affected the proficiency of the brain-machine interface and were implemented to improve BCI control, underlining the clinical potential of the present approach.

These findings link basic human neuroscience and neurotechnology with clinical translation. We show that primary motor cortex (M1) encodes information related to action and sensing, but also sensorimotor and for the first time that M1 encodes subjective agency signals, which in turn are relevant for clinical applications of brain-machine interfaces, but also for the impact of neurotechnology on the sense of agency and its ethical, legal, and social impact.