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The ability to control a prosthetic device directly from the neocortex has been demonstrated in rats, monkeys and humans. Here we investigate whether neural control can be accomplished in situations where (1) subjects have not received prior motor training to control the device (naive user) and (2) the neural encoding of movement parameters in the cortex is(More)
Current neuroprosthetic systems based on electro-physiological recording have an extended, yet finite working lifetime. Some posited lifetime-extension solutions involve improving device biocompatibility or suppressing host immune responses. Our objective was to test an alternative solution comprised of applying a voltage pulse to a microelectrode site,(More)
Reactive tissue encapsulation of chronically implanted microelectrode probes can preclude long-term recording of extracellular action potentials. We investigated an intervention strategy for functionally encapsulated microelectrode sites. This method, known as "rejuvenation," involved applying a +1.5 V dc bias to an iridium site for 4 s. Previous studies(More)
The reactive response of brain tissue to implantable intracortical microelectrodes is thought to negatively affect their recordable signal quality and impedance, resulting in unreliable longitudinal performance. The relationship between the progression of the reactive tissue into a glial scar and the decline in device performance is unclear. We show that(More)
Accurate assessment of brain-implantable microdevice bio-integration remains a formidable challenge. Prevailing histological methods require device extraction prior to tissue processing, often disrupting and removing the tissue of interest which had been surrounding the device. The Device-Capture Histology method, presented here, overcomes many limitations(More)
Direct recording from sequential processing stations within the brain has provided opportunity for enhancing understanding of important neural circuits, such as the corticothalamic loops underlying auditory, visual, and somatosensory processing. However, the common reliance upon microwire-based electrodes to perform such recordings often necessitates(More)
The successful use of implantable neural microelectrodes as neuroprosthetic devices depends on the mitigation of the reactive tissue response of the brain. One of the factors affecting the ultimate severity of the reactive tissue response and the in vivo electrical properties of the microelectrodes is the initial adsorption of proteins onto the surface of(More)
OBJECTIVE Somatosensation is critical for effective object manipulation, but current upper limb prostheses do not provide such feedback to the user. For individuals who require use of prosthetic limbs, this lack of feedback transforms a mundane task into one that requires extreme concentration and effort. Although vibrotactile motors and sensory(More)
Sensory cortical prostheses have potential to aid people suffering from blindness, deafness and other sensory deficits. However, research to date has shown that sensation thresholds via epicortical stimulation are surprisingly large. These thresholds result in potentially deleterious electrical currents, as well as large activation volumes. Large activation(More)
Chronic microstimulation-based devices are being investigated to treat conditions such as blindness, deafness, pain, paralysis, and epilepsy. Small-area electrodes are desired to achieve high selectivity. However, a major trade-off with electrode miniaturization is an increase in impedance and charge density requirements. Thus, the development of novel(More)