Restoration of function after brain damage using a neural prosthesis

Restoration of function after brain damage using a neural prosthesis

1. David J. Guggenmos^a,^b,¹,
2. Meysam Azin^c,²,
3. Scott Barbay^a,^b,
4. Jonathan D. Mahnken^d,
5. Caleb Dunham^a,^b,
6. Pedram Mohseni^c, and
7. Randolph J. Nudo^a,^b,³

Author Affiliations

1. Edited* by Michael Merzenich, Brain Plasticity Institute, San Francisco, CA, and approved November 15, 2013 (received for review September 6, 2013)

Significance

Closed-loop systems, or brain–machine–brain interfaces (BMBIs), have not been widely developed for brain repair. In this study, we targeted spared motor and somatosensory regions of the rat brain after traumatic brain injury for establishment of a functional bridge using a battery-powered microdevice. The results show that by using discriminated action potentials as a trigger for stimulating a distant cortical location, rapid recovery of fine motor skills is facilitated. This study provides strong evidence that BMBIs can be used to bridge damaged neural pathways functionally and promote recovery after brain injury. Although this study is restricted to a rodent model of TBI, it is likely that the approach will also be applicable to other types of acquired brain injuries.

Abstract

Neural interface systems are becoming increasingly more feasible for brain repair strategies. This paper tests the hypothesis that recovery after brain injury can be facilitated by a neural prosthesis serving as a communication link between distant locations in the cerebral cortex. The primary motor area in the cerebral cortex was injured in a rat model of focal brain injury, disrupting communication between motor and somatosensory areas and resulting in impaired reaching and grasping abilities. After implantation of microelectrodes in cerebral cortex, a neural prosthesis discriminated action potentials (spikes) in premotor cortex that triggered electrical stimulation in somatosensory cortex continuously over subsequent weeks. Within 1 wk, while receiving spike-triggered stimulation, rats showed substantially improved reaching and grasping functions that were indistinguishable from prelesion levels by 2 wk. Post hoc analysis of the spikes evoked by the stimulation provides compelling evidence that the neural prosthesis enhanced functional connectivity between the two target areas. This proof-of-concept study demonstrates that neural interface systems can be used effectively to bridge damaged neural pathways functionally and promote recovery after brain injury.

• brain–machine–brain interface
• neural plasticity
• traumatic brain injury
• closed-loop
• long-term potentiation

Footnotes

• ¹Present address: Department of Neurobiology, Duke University, Durham, NC 27705.
• ²Present address: Qualcomm CDMA Technologies, Qualcomm, Inc., San Diego, CA 92121.
• ³To whom correspondence should be addressed. E-mail: rnudo@kumc.edu.

• Author contributions: D.J.G., M.A., P.M., and R.J.N. designed research; D.J.G., M.A., and S.B. performed research; D.J.G., M.A., J.D.M., C.D., P.M., and R.J.N. analyzed data; and D.J.G., M.A., J.D.M., P.M., and R.J.N. wrote the paper.
• The authors declare no conflict of interest.
• *This Direct Submission article had a prearranged editor.
• This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1316885110/-/DCSupplemental.

Freely available online through the PNAS open access option.