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Neuronal ensemble control of prosthetic devices by a human with tetraplegia


Neuromotor prostheses (NMPs) aim to replace or restore lost motor functions in paralysed humans by routeing movement-related signals from the brain, around damaged parts of the nervous system, to external effectors. To translate preclinical results from intact animals to a clinically useful NMP, movement signals must persist in cortex after spinal cord injury and be engaged by movement intent when sensory inputs and limb movement are long absent. Furthermore, NMPs would require that intention-driven neuronal activity be converted into a control signal that enables useful tasks. Here we show initial results for a tetraplegic human (MN) using a pilot NMP. Neuronal ensemble activity recorded through a 96-microelectrode array implanted in primary motor cortex demonstrated that intended hand motion modulates cortical spiking patterns three years after spinal cord injury. Decoders were created, providing a ‘neural cursor’ with which MN opened simulated e-mail and operated devices such as a television, even while conversing. Furthermore, MN used neural control to open and close a prosthetic hand, and perform rudimentary actions with a multi-jointed robotic arm. These early results suggest that NMPs based upon intracortical neuronal ensemble spiking activity could provide a valuable new neurotechnology to restore independence for humans with paralysis.

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The authors thank J. Joseph and D. Morris for assistance; L. Mermel for clinical planning advice; V. Zerris and M. Park for surgical assistance; G. Polykoff for clinical trial assistance; W. Truccolo for power spectral density analysis development; and the employees of Cyberkinetics for device engineering, manufacturing and clinical trial design and management. The authors also thank MN for his participation in this trial, and the nursing staff at his assisted care facility for their assistance. The authors are grateful to M. Serra and Sargent Rehabilitation Center, the study site, for administrative support. The photograph of MN (Fig. 1) is copyright 2005 Rick Friedman. This work was supported by Cyberkinetics Neurotechnology Systems, Inc.

Author information

Competing interests

L.R.H.: Clinical trial support, Cyberkinetics Neurotechnology Systems (CKI); G.M.F.: stock holdings, consultant, CKI; J.A.M.: principal investigator, consultant, CKI; M.D.S.: salary, consultant, stock holdings, CKI; M.S.: salary, stock options, CKI; A.H.C.: salary, stock options, stock holdings, CKI; A.B.: salary, stock options, CKI; D.C.: clinical trial support, CKI; R.D.P.: clinical trial support, CKI; J.P.D.: Chief Scientific Officer, compensation, stock holdings, director, CKI.

Correspondence to John P. Donoghue.

Supplementary information

Supplementary Notes

This file contains Supplementary Figures 1 and 2 and legends, Supplementary Methods and Results, Supplementary Discussion, Supplementary Video Legends and Supplementary References. The two figures illustrate neuronal selectivity for imagined and performed movements, and center-out task performance with an alternate post-hoc control. Also reported is additional information regarding signal quality and variety; MI activity during neural cursor control; center-out task; grid task; summary of neurophysiologic findings; comparison with previous work; video legends. (PDF 176 kb)

Supplementary Video 1

Center-Out task. (MOV 3821 kb)

Supplementary Video 2

Video showing use of a computer interface with the neural cursor. (MOV 1645 kb)

Supplementary Video 3

Neurally-controlled television. (MOV 1608 kb)

Supplementary Video 4

Neural "Pong". (MOV 2978 kb)

Supplementary Video 5

Neural "HeMan" game. (MOV 2888 kb)

Supplementary Video 6

Direct neural control of a prosthetic hand. MN was initially instructed to move a neural cursor "up" to open the hand, and "down" to close the hand. (MOV 2330 kb)

Supplementary Video 7

Transport of an object from one location to another via direct neural control of a multi-articulated robot arm. (MOV 1745 kb)

Supplementary Video 8

Trial Participant #2 performing Center-Out task. (MOV 7551 kb)

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Figure 1: Intracortical sensor and placement, participant 1.
Figure 2: Electrical recordings from a sample of four electrodes.
Figure 3: Neuronal selectivity for imagined and performed movements.
Figure 4: Directional tuning during centre-out task.
Figure 5: Reconstruction of neural cursor position during pursuit tracking.
Figure 6: Centre-out task performance.


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