Restoring the Sense of Touch Using a Sensorimotor Demultiplexing Neural Interface.

Paralyzed muscles can be reanimated following spinal cord injury (SCI) using a brain-computer interface (BCI) to enhance motor function alone. Importantly, the sense of touch is a key component of motor function. Here, we demonstrate that a human participant with a clinically complete SCI can use a BCI to simultaneously reanimate both motor function and the sense of touch, leveraging residual touch signaling from his own hand.

Clinically Significant Gains in Skillful Grasp Coordination by an Individual With Tetraplegia Using an Implanted Brain-Computer Interface With Forearm Transcutaneous Muscle Stimulation.

Objective: To demonstrate naturalistic motor control speed, coordinated grasp, and carryover from trained to novel objects by an individual with tetraplegia using a brain-computer interface (BCI)-controlled neuroprosthetic.

Design: Phase I trial for an intracortical BCI integrated with forearm functional electrical stimulation (FES). Data reported span postimplant days 137 to 1478.

A Characterization of Brain-Computer Interface Performance Trade-Offs Using Support Vector Machines and Deep Neural Networks to Decode Movement Intent.

Laboratory demonstrations of brain-computer interface (BCI) systems show promise for reducing disability associated with paralysis by directly linking neural activity to the control of assistive devices. Surveys of potential users have revealed several key BCI performance criteria for clinical translation of such a system. Of these criteria, high accuracy, short response latencies, and multi-functionality are three key characteristics directly impacted by the neural decoding component of the BCI system, the algorithm that translates neural activity into control signals.

Meeting brain-computer interface user performance expectations using a deep neural network decoding framework.

Brain-computer interface (BCI) neurotechnology has the potential to reduce disability associated with paralysis by translating neural activity into control of assistive devices. Surveys of potential end-users have identified key BCI system features, including high accuracy, minimal daily setup, rapid response times, and multifunctionality. These performance characteristics are primarily influenced by the BCI's neural decoding algorithm, which is trained to associate neural activation patterns with intended user actions.

Extracting wavelet based neural features from human intracortical recordings for neuroprosthetics applications.

Background: Understanding the long-term behavior of intracortically-recorded signals is essential for improving the performance of Brain Computer Interfaces. However, few studies have systematically investigated chronic neural recordings from an implanted microelectrode array in the human brain.

Methods: In this study, we show the applicability of wavelet decomposition method to extract and demonstrate the utility of long-term stable features in neural signals obtained from a microelectrode array implanted in the motor cortex of a human with tetraplegia.

Dexterous Control of Seven Functional Hand Movements Using Cortically-Controlled Transcutaneous Muscle Stimulation in a Person With Tetraplegia.

Individuals with tetraplegia identify restoration of hand function as a critical, unmet need to regain their independence and improve quality of life. Brain-Computer Interface (BCI)-controlled Functional Electrical Stimulation (FES) technology addresses this need by reconnecting the brain with paralyzed limbs to restore function. In this study, we quantified performance of an intuitive, cortically-controlled, transcutaneous FES system on standardized object manipulation tasks from the Grasp and Release Test (GRT).

Neuroprosthetic-enabled control of graded arm muscle contraction in a paralyzed human.

Neuroprosthetics that combine a brain computer interface (BCI) with functional electrical stimulation (FES) can restore voluntary control of a patients' own paralyzed limbs. To date, human studies have demonstrated an "all-or-none" type of control for a fixed number of pre-determined states, like hand-open and hand-closed. To be practical for everyday use, a BCI-FES system should enable smooth control of limb movements through a continuum of states and generate situationally appropriate, graded muscle contractions.

Big data challenges in decoding cortical activity in a human with quadriplegia to inform a brain computer interface.

Recent advances in Brain Computer Interfaces (BCIs) have created hope that one day paralyzed patients will be able to regain control of their paralyzed limbs. As part of an ongoing clinical study, we have implanted a 96-electrode Utah array in the motor cortex of a paralyzed human. The array generates almost 3 million data points from the brain every second.

Effects of passive dendritic tree properties on the firing dynamics of a leaky-integrate-and-fire neuron.

We study the effects of dendritic tree topology and biophysical properties on the firing dynamics of a leaky-integrate-and-fire (LIF) neuron that explicitly includes spiking dynamics. We model the dendrites as a multi-compartment tree with passive dynamics. Owing to the simplicity of the system, we obtain the full analytical solution for the model which we use to derive a lower dimensional return map that captures the complete dynamics of the system.

A Multi-Area Stochastic Model for a Covert Visual Search Task.

Decisions typically comprise several elements. For example, attention must be directed towards specific objects, their identities recognized, and a choice made among alternatives. Pairs of competing accumulators and drift-diffusion processes provide good models of evidence integration in two-alternative perceptual choices, but more complex tasks requiring the coordination of attention and decision making involve multistage processing and multiple brain areas.

Constructing Precisely Computing Networks with Biophysical Spiking Neurons.

Unlabelled: While spike timing has been shown to carry detailed stimulus information at the sensory periphery, its possible role in network computation is less clear. Most models of computation by neural networks are based on population firing rates. In equivalent spiking implementations, firing is assumed to be random such that averaging across populations of neurons recovers the rate-based approach.

Effects of moderate noise on a limit cycle oscillator: counterrotation and bistability.

The effects of noise on the dynamics of nonlinear systems is known to lead to many counterintuitive behaviors. Using simple planar limit cycle oscillators, we show that the addition of moderate noise leads to qualitatively different dynamics. In particular, the system can appear bistable, rotate in the opposite direction of the deterministic limit cycle, or cease oscillating altogether.

The robustness of phase-locking in neurons with dendro-dendritic electrical coupling.

We examine the effects of dendritic filtering on the existence, stability, and robustness of phase-locked states to heterogeneity and noise in a pair of electrically coupled ball-and-stick neurons with passive dendrites. We use the theory of weakly coupled oscillators and analytically derived filtering properties of the dendritic coupling to systematically explore how the electrotonic length and diameter of dendrites can alter phase-locking. In the case of a fixed value of the coupling conductance (gc) taken from the literature, we find that repeated exchanges in stability between the synchronous and anti-phase states can occur as the electrical coupling becomes more distally located on the dendrites.

Can post-error dynamics explain sequential reaction time patterns?

We investigate human error dynamics in sequential two-alternative choice tasks. When subjects repeatedly discriminate between two stimuli, their error rates and reaction times (RTs) systematically depend on prior sequences of stimuli. We analyze these sequential effects on RTs, separating error and correct responses, and identify a sequential RT tradeoff: a sequence of stimuli which yields a relatively fast RT on error trials will produce a relatively slow RT on correct trials and vice versa.

Constraints on the use of lifespan-shortening Wolbachia to control dengue fever.

Dengue fever, a viral disease spread by the mosquito Aedes aegypti, affects 50-100 million people a year in many tropical countries. Because the virus must incubate within mosquito hosts for two weeks before being able to transmit the infection, shortening the lifespan of mosquitoes may curtail dengue transmission. We developed a continuous time reaction-diffusion model of the spatial spread of Wolbachia through a population of A.

Effects of dendritic load on the firing frequency of oscillating neurons.

We study the effects of passive dendritic properties on the dynamics of neuronal oscillators. We find that the addition of a passive dendrite can sometimes have counterintuitive effects on firing frequency. Specifically, the addition of a hyperpolarized passive dendritic load can either increase, decrease, or have negligible effects on firing frequency.

Effects of lacidipine on vascular responses in patients with coronary artery disease.

Background: To evaluate the effects of the calcium channel blocker lacidipine on vascular responses, such as endothelial function and carotid intima-media thickness (IMT), and on levels of high-sensitivity C-reactive protein (hs-CRP) in patients with coronary artery disease (CAD).

Methods: Endothelial function was assessed by measuring the flow-mediated vasodilation (FMD) of the brachial artery and IMT was measured in the common, bifurcating, and in the internal carotid artery by using high-resolution ultrasound. The study population consisted of 96 consecutive patients [mean age 60 years, male (n) = 70] who showed at least one coronary artery narrowed by more than 50% (coronary angiography).

Effects of low-dose atorvastatin on vascular responses in patients undergoing percutaneous coronary intervention with stenting.

Background: The primary endpoint of this study was to evaluate the effects of low-dose atorvastatin on carotid intima-media thickness (IMT) and endothelial function, and the secondary endpoint comprised restenosis and target lesion revascularization (TLR) in patients undergoing percutaneous coronary intervention (PCI) with stenting for the treatment of coronary artery disease.

Methods: Two hundred five consecutive patients (mean age, 60 years) undergoing PCI were prospectively randomized to usual therapy (control group, n = 100) or to 10 mg of atorvastatin daily plus usual therapy (statin group, n = 105). Carotid IMT, endothelial function (flow-mediated dilatation [FMD] of the brachial artery), and coronary angiograms were taken before the study and 6 months after randomization.

Impact of left ventricular ejection fraction on endothelial function in patients with coronary artery disease.

Background: Endothelial dysfunction is present in patients with coronary artery disease (CAD) or with congestive heart failure.

Hypothesis: This study was performed to evaluate the impact of systolic heart function on endothelial function in patients with CAD.

Methods: The study population consisted of 283 consecutive patients (mean age 59 years, 176 men) undergoing coronary angiography.

Significance of the intima-media thickness of the thoracic aorta in patients with coronary atherosclerosis.

Background: The prevalence and clinical significance of atherosclerotic aortic disease have now been documented in a variety of patient populations by use of transesophageal echocardiography (TEE). There are many reports that atherosclerotic aortic plaques detected by TEE are a marker for coronary artery disease (CAD).

Hypothesis: The study was undertaken to evaluate the significance of the intima-media thickness (IMT) and formation of atherosclerotic plaques of the thoracic aorta (TA) in patients with CAD, especially in terms of a correlation between the IMT of the TA and the extent of coronary atherosclerosis.

New approaches to overcome tolerance to nitrates.

In isolated cells (vascular smooth muscle, endothelium, platelets), perfused hearts, in vivo experiments, conscious instrumented animals, and in human subjects the induction of tachyphylaxis and tolerance to various exogenous NO-donors was analyzed. Various ways to circumvent tolerance were successfully tested. Different nitrovasodilators were associated with different rates and magnitudes of generation of tolerance and reactive oxygen radicals (ROS) in all models tested, beginning with PETN (pentaerithrityltetranitrate) (lowest rate) and concluding with GTN (highest rate).

Postprandial hypertriglyceridemia-induced endothelial dysfunction in healthy subjects is independent of lipid oxidation.

Background: To analyze the effects of postprandial hypertriglyceridemia with or without antioxidant supplementation-on endothelial function as related to lipid oxidation in healthy young subjects.

Methods And Results: Ten healthy male subjects (mean age: 26 years) were examined three times in fasting state (10 hours) following a high-fat meal, a low-fat meal, or a high-fat meal with additional antioxidant vitamin E (800 IU), respectively. Serum triglycerides significantly increased 2 and 4 hours after eating the high-fat meal with or without additional vitamin E.