Sea cucumbers, like other echinoderms, have the ability to rapidly and reversibly alter stiffness of their inner dermis. It has been proposed that modulus this tissue is controlled by regulating interactions among collagen fibrils, which reinforce a low-modulus matrix. We report on family polymer nanocomposites, mimic architecture display similar chemoresponsive mechanic adaptability. Materials based rubbery host rigid cellulose nanofibers exhibit reversible reduction factor 40 tensile...

Electrical stimulation, using patterned intensity, applied through cuff-type peripheral nerve interfaces provided stable touch perceptions in the fingers, thumb, and hand of two subjects with upper limb loss for 16 to 24 months.

One of the important goals peripheral nerve electrode development is to design an for selective recruitment different functions a common trunk. A challenging task gaining access central axon populations. In this paper, simple that takes advantage neural plasticity reshape presented. The flat interface (FINE) reshapes into geometry increase surface area and move populations close surface. was implanted acutely on sciatic eight cats. FINE can significantly fascicles (p<0.0001) while...

Objective. The mechanisms underlying intracortical microelectrode encapsulation and failure are not well understood. A leading hypothesis implicates the role of mechanical mismatch between rigid implant materials much softer brain tissue. Previous work has established benefits compliant on reducing early neuroinflammatory events. However, recent studies late onset a disease-like neurodegenerative state. Approach. In this study, we implanted mechanically-adaptive materials, which initially...

Electrical connections between nerves and a prosthetic device enable amputees to discern precise, graded sensory intensity ranging from light touch intense pressure.

Objective. Tactile feedback is critical to grip and object manipulation. Its absence results in reliance on visual auditory cues. Our objective was assess the effect of sensory task performance individuals with limb loss. Approach. Stimulation peripheral nerves using implanted cuff electrodes provided two subjects intensity proportional forces thumb, index, middle fingers their prosthetic hand during Both perceived sensation phantom at locations corresponding hand. A bend sensor measured...

The loss of a hand has many psychosocial repercussions. While advanced multi-articulated prostheses can improve function, without sensation, they cannot restore the full experience and connection hand. Direct nerve interfaces naturalistic sensation to amputees. Our sensory restoration system produced tactile proprioceptive sensations on via neural stimulation through chronically implanted electrodes. In this study, upper limb amputees used sensory-enabled prosthesis in their homes...

The hypothesis is that the mechanical mismatch between brain tissue and microelectrodes influences inflammatory response. Our unique, mechanically adaptive polymer nanocomposite enabled this study within cerebral cortex of rats. initial tensile storage modulus 5 GPa decreases to 12 MPa 15 min under physiological conditions. response was compared surface-matched, stiffer implants traditional wires (411 GPa) coated with identical substrate implanted on contralateral side. Both were tethered....

Objective. Stability and selectivity are important when restoring long-term, functional sensory feedback in individuals with limb-loss. Our objective is to demonstrate a chronic, clinical neural stimulation system for providing selective response two upper-limb amputees. Approach. Multi-contact cuff electrodes were implanted the median, ulnar, radial nerves of upper-limb. Main results. Nerve produced on 19 20 contacts 16 subjects 1 2, respectively. Stimulation elicited multiple, distinct...

We recently introduced a series of stimuli-responsive, mechanically adaptive polymer nanocomposites. Here, we report the first application these bio-inspired materials as substrates for intracortical microelectrodes. Our hypothesis is that ideal electrode should be initially stiff to facilitate minimal trauma during insertion into cortex, yet become compliant match stiffness brain tissue and minimize forces exerted on tissue, attenuating inflammation. Microprobes created from reinforced...

Nine spiral nerve cuff electrodes were implanted in two human subjects for up to three years with no adverse functional effects. The objective of this study was look at the long term and muscle response stimulation through electrodes. conduction velocity remained within clinically accepted range entire testing period. thresholds stabilized after approximately 20 weeks. variability activation over time not different from muscle-based used electrical systems. Three had multiple, independent...

Sensory systems adapt their sensitivity to ambient stimulation levels improve responsiveness changes in stimulation. The sense of touch is also subject adaptation, as evidenced by the desensitization produced prolonged vibratory skin. Electrical nerves elicits tactile sensations that can convey feedback for bionic limbs. In this study, we investigate whether artificial despite fact peripheral mechanotransducers are bypassed.Using well-established psychophysical paradigms, characterize time...

Abstract Objective . Sensory input in lower-limb amputees is critically important to maintaining balance, preventing falls, negotiating uneven terrain, responding unexpected perturbations, and developing the confidence required for societal participation public interactions unfamiliar environments. Despite noteworthy advances robotic prostheses amputees, such as microprocessor knees powered ankles, natural somatosensory feedback from lost limb has not yet been incorporated current prosthetic...

Somatosensory feedback of the hand is essential for object identification. Without somatosensory feedback, individuals cannot reliably determine size or compliance an object. Electrical nerve stimulation can restore localized tactile and proprioceptive with intensity discrimination capability similar to natural sensation. We hypothesized that adding artificial somatosensation improves recognition accuracy when using a prosthesis. To test this hypothesis, we provided different forms sensory...

Upper limb prostheses are specialized tools, and skilled operation is learned by amputees over time. Recently, neural using implanted peripheral nerve interfaces have enabled advances in artificial somatosensory feedback that can improve prosthesis outcomes. However, the effect of sensory learning on somatosensation has not been studied, despite its known influence intact analogous neuroprostheses. Sensory involves changes perception interpretation may further functional psychosocial In this...

Electrical stimulation of the peripheral nerves has been shown to be effective in restoring sensory and motor functions lower upper extremities. This neural can applied via non-penetrating spiral nerve cuff electrodes, though minimal information published regarding their long-term performance for multiple years after implantation.Since 2005, 14 human volunteers with cervical or thoracic spinal cord injuries, limb amputation, were chronically implanted a total 50 electrodes on 10 different...

Electrical stimulation of the peripheral nerves human participants provides a unique opportunity to study neural determinants perceptual quality using causal manipulation. A major challenge in coding touch has been isolate role spike timing—at scale milliseconds or tens milliseconds—in shaping sensory experience. In present study, we address this question by systematically varying pulse frequency (PF) electrical trains delivered seven with upper and lower extremity limb loss via chronically...

Functional electrical stimulation (FES) can restore limb movements through electrically initiated, coordinated contractions of paralyzed muscles. The peripheral nerve is an attractive site for using cuff electrodes. Many applications will require the electrode to selectively activate many smaller populations axons within a common trunk. purpose this study computationally model performance flat interface (FINE) on proximal femoral standing and stepping applications. Simulations investigated...

The number of applications using neural prosthetic interfaces is expanding. Computer models are a valuable tool to evaluate stimulation techniques and electrode designs. Although our understanding anatomy has improved, its impact on the effects not well understood. This study evaluated fascicle perineurial thickness, diameter, position axonal excitation thresholds population recruitment finite element NEURON simulations. thickness human fascicles was found be 3.0% plusmn 1.0% diameter....