Abstract
Recording the motor output of the central nervous system from the cervical spinal cord was investigated as a method of generating voluntary command signals, potentially to be used in quadriplegic individuals. Corticospinal volleys evoked by motor cortex stimulation were recorded from the spinal cord surface with multicontact electrodes in anesthetized cats. The multicontact recordings were analyzed for their information-carrying capacity as a neural interface. Neural signals resulting from the stimulation of various points in the motor cortex were considered as symbols of an alphabet that were sent through a discrete information channel. The information capacity of this channel at the thermal noise level of the electrode contacts was calculated. The maximum information rate was 1.57 bits in a trial for a 4-symbol alphabet. The background noise that reduces the information rate to 50% of its maximum theoretical value was defined as the half-bitrate–noise–tolerance (HBR-NoiseTol) and used as a measure of symbol distinguishability. The HBR-NoiseTol for all trials on average was 24 ± 12%, 18 ± 10%, and 15 ± 9% for interfaces with 2-, 3-, and 4-symbol alphabets (n = 11 trials). The average peak-to-peak amplitude of the neural volleys was 13.5 ± 6.7 μV (n = 11). These results suggest that the corticospinal signals can be recorded with spatial selectivity from the spinal cord surface and thus warrant further investigation of their potential use for a spinal cord–computer interface.
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REFERENCES
Burke, D., R. Hicks, J. Stephen, I. Woodforth, and M. Crawford. Assessment of corticospinal and somatosensory conduction simultaneously during scoliosis surgery. Electroencephal. Clin. Neurophys. 85:388–396, 1992.
Boyd, S. G., J. C. Rothwell, J. M. A. Cowan, P. J. Webb, T. Morley, P. Asselman, and C. D. Marsden. A method of monitoring function in corticospinal pathways during scoliosis surgery with a note on motor conduction velocities. J. Neurol. Neurosurg. Psychiat. 49:251–257, 1986.
Chapin, J. K., K. A. Moxon, R. S. Markowitz, and M. A. L. Nicolelis. Real-time control of a robot arm using simultaneously recorded neurons in the motor cortex. Nat. Neurosci. 2:664–670, 1999.
Chen, Y., P. R. Christensen, K. D. Strange, and J. A. Hoffer. Multi-channel recordings from peripheral nerves. 2: Measurement of selectivity. In: Proceedings of the Second Annual IFESS Conference and Neural Prosthesis, BC, Canada, 1997.
Dawnay, N. A. H., and P. Glees. Somatotopic analysis of fiber and terminal distribution in the primate corticospinal pathway. Dev. Brain Res. 26:115–123, 1986.
Goode, G. E., and D. E. Haines. Origin, course, and termination of corticospinal fibers in a prosimian primate (Galago). Brain Behav. Evol. 12:334–361, 1975.
Hern, J. E. C., S. Landgren, C. G. Phillips, and R. Porter. Selective excitation of corticofugal neurons by surface-anodal stimulation of the baboon's motor cortex. J. Physiol. 161:73–90, 1962.
Inghilleri, M., A. Berardelli, B. Cioni, G. Cruccu, M. Meglio, and M. Manfredi. Corticospinal potentials after transcranial stimulation in humans. J. Neurol. Neurosug. Psychiat. 52:970–974, 1989.
Jeffery, N. D., and M. Fitzgerald. Lack of topographical organization of the corticospinal tract in the cervical spinal cord of the adult rat. Brain Res. 833:315–318, 1999.
Lichtenberg, B. K., and C. J. DeLuca. Distinguishability of functionally distinct evoked neuroelectric signals on the surface of a nerve. IEEE Tran. Biomed. Eng. 26:228–237, 1979.
Loughnan, B. A., S. K. Anderson, M. A. Hetreed, P. F. Weston, S. G. Boyd, and G. M. Hall. Effects of halothane on motor evoked potentials recorded in the extradural space. Br. J. Anaesth. 63:561–564, 1989.
Moye, R. J., A. Pailet, and M. W. Smith. Clinical use of xylazine in dogs and cats. Vet. Med. Small Anim. Clin. 68:236–241, 1973.
Pelosi, L., G. Caruso, and P. Balbi. Characteristics of spinal potentials to transcranial motor cortex stimulation: Intraoperative recording. In: Non-Invasive Stimulation of Brain and Spinal Cord: Fundamentals and Clinical Applications, edited by P. M. Rossini and C. D. Marsden. New York: Alan R. Liss, 1988, pp. 297–304.
Pratila, M. G., and S. V. Pratila. Anesthetic agents and cardiac electromechanical activity. Anesthesiology 49:338–355, 1978.
Sahin, M. Noise tolerance as a measure of channel discrimination for multi-channel neural interfaces. In: 23rd Annual Internation Conference of the IEEE Engineering in Medicine and Biological Socience, Istanbul, Turkey, 2001.
Sahin, M. Selective recordings of motor signals from the corticospinal tract. In: Proceedings of the Sixth Annual IFESS Conference and Neural Prosthesis, Cleveland, OH, 2001.
Sahin, M., and D. M. Durand. Selective recordings with a multi-contact nerve cuff electrode. In: 18th Annual International Conference of the IEEE Engineering in Medicine and Biological Science, Amsterdam, the Netherlands, 1996.
Schwartz, A. B. Motor Cortical activity during drawing movements: Population representation during sinusoid tracing. J. Neurophys. 70:28–36, 1993.
Shannon, C. E., and W. Weaver. The Mathematical Theory of Communication. Urbana: The University of Illinois Press, 1949, pp. 34–48.
Tie, Y., and M. Sahin. Separation of multi-channel spinal cord recordings using unsupervised adaptive filtering. In: Proceedings of the Second Joint EMBS/BMES Conference, Houston, TX, October 2002.
Wessberg, J., C. R. Stambaugh, J. D. Kralik, P. D. Beck, M. Laubach, K. J. Chapin, J. Kim, J. S. Biggs, M. A. Srinivasan, A. Mandayam, Nicolelis, and A. L. Miguel. Real-time prediction of hand trajectory by ensembles of cortical neurons in primates. Nature 408:361–365, 2000.
Wolfaw, R. J., N. Birbaumer, W. J. Heetderks, D. J. McFarland, P. H. Peckham, G. Schalk, E. Donchin, L. A. Quotrono, C. J. Robinson, and T. M. Vaughan. Brain-computer interface technology: A review of the first international meeting. IEEE Tran. Rehab. Eng. 8:164–173, 2000.
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Sahin, M. Information Capacity of the Corticospinal Tract Recordings as a Neural Interface. Annals of Biomedical Engineering 32, 823–830 (2004). https://doi.org/10.1023/B:ABME.0000030258.26583.94
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DOI: https://doi.org/10.1023/B:ABME.0000030258.26583.94