Restoration of function after brain damage using a neural prosthesis

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 proofof-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 T he view of the brain as a collection of independent anatomical modules, each with discrete functions, is currently undergoing radical change. New evidence from neurophysiological and neuroanatomical experiments in animals, as well as neuroimaging studies in humans, now suggests that normal brain function can be best appreciated in the context of the complex arrangements of functional and structural interconnections among brain areas. Although mechanistic details are still under refinement, synchronous discharge of neurons in widespread areas of the cerebral cortex appears to be an emergent property of neuronal networks that functionally couple remote locations (1). It is now recognized that not only are discrete regions of the brain damaged in injury or disease but, perhaps more importantly, the interconnections among uninjured areas are disrupted, potentially leading to many of the functional impairments that persist after brain injury (2). Likewise, plasticity of brain interconnections may partially underlie recovery of function after injury (3).Technological efforts to restore brain function after injury have focused primarily on modulating the excitability of focal regions in uninjured parts of the brain (4). Purportedly, increasing the excitability of neurons involved in adaptive plasticity expands the neural substrate potentially involved in functional recovery. However, no methods are yet available to alter the functional connectivity between spared brain regions directly, with the intent to restore normal communication patterns. The present paper tests the hypothesis that an artificial communication link between uninjured regions of the...

Targeted, activity-dependent spinal stimulation produces long-lasting motor recovery in chronic cervical spinal cord injury

“…Additionally, this finding strongly suggests that the enhanced recovery afforded by TADSS is an effect unique to activity-dependent conditioning of specific neural circuits post-SCI. Consistent with this notion, focal, activitydependent intracortical stimulation has recently been shown to accelerate motor recovery over focal, open-loop intracortical stimulation after mild traumatic brain injury (16). Focal but open-loop ISMS was recently shown to improve forelimb recovery after cervical SCI in rats (17) but to a much lesser extent than we Fig.…”

Review article: DOES INTRA-ARTERIAL HEPARIN FLUSHING (IAHF) CAN ACTUALLY INCREASE MANUAL MUSCLE TEST (MMT) SCORE IN CHRONIC ISCHEMIC STROKE PATIENTS?

“…In the discussion was written as follows: "Lesion in motor cortex especially in M1 region in stroke accident and brain trauma will ended up as necrosis in focal area that finally will cause the loss of M1 output to spinal cord and in the end will cause functional disability" (Guggenmos et al 2013). This is the abstract of Guggenmos: "Neural interface systems are becoming increasingly more feasible for brain repair strategies.…”

Optimization of Stimulation Parameters for Targeted Activation of Multiple Neurons Using Closed-Loop Search Methods

“…The prosthesis field is expansive, including peripheral and cortical prostheses, with applications including restoration of lost motor and sensory function in artificial limbs; cochlear prostheses for restoring audition [5,6]; retinal prostheses for restoring vision [7][8][9]; and cortical prostheses for inducing sensory percepts and reading motor intent directly from the brain [10][11][12][13][14][15][16]. An effective prosthesis must encode a variety of unique stimuli.…”