title: Point-and-click cursor control with an intracortical neural interface system by humans with tetraplegia.
abstract: We present a point-and-click intracortical neural interface system (NIS) that enables humans with tetraplegia to volitionally move a 2-D computer cursor in any desired direction on a computer screen, hold it still, and click on the area of interest. This direct brain-computer interface extracts both discrete (click) and continuous (cursor velocity) signals from a single small population of neurons in human motor cortex. A key component of this system is a multi-state probabilistic decoding algorithm that simultaneously decodes neural spiking activity of a small population of neurons and outputs either a click signal or the velocity of the cursor. The algorithm combines a linear classifier, which determines whether the user is intending to click or move the cursor, with a Kalman filter that translates the neural population activity into cursor velocity. We present a paradigm for training the multi-state decoding algorithm using neural activity observed during imagined actions. Two human participants with tetraplegia (paralysis of the four limbs) performed a closed-loop radial target acquisition task using the point-and-click NIS over multiple sessions. We quantified point-and-click performance using various human-computer interaction measurements for pointing devices. We found that participants could control the cursor motion and click on specified targets with a small error rate (< 3% in one participant). This study suggests that signals from a small ensemble of motor cortical neurons (∼40) can be used for natural point-and-click 2-D cursor control of a personal computer.
authors.affiliation: Department of Computer Science, Brown University, Providence, RI 02912, USA. spkim@cs.brown.edu
authors.forename: Sung-Phil
authors.initials: SP
authors.lastname: Kim
authors.forename: John D
authors.initials: JD
authors.lastname: Simeral
authors.forename: Leigh R
authors.initials: LR
authors.lastname: Hochberg
authors.forename: John P
authors.initials: JP
authors.lastname: Donoghue
authors.forename: Gerhard M
authors.initials: GM
authors.lastname: Friehs
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Black
mesh_terms: D000328:Adult; D000465:Algorithms; D000690:Amyotrophic Lateral Sclerosis / Q000150:complications; D030141:Feedback, Psychological; D005260:Female; D006801:Humans; D033182:Intention; D007858:Learning; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D015233:Models, Statistical; D009044:Motor Cortex / Q000166:cytology / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D011782:Quadriplegia / Q000209:etiology; D020521:Stroke / Q000150:complications; D014584:User-Computer Interface