Selective peripheral nerve recordings from nerve cuff electrodes using convolutional neural networks.

Objective: Recording and stimulating from the peripheral nervous system are becoming important components in a new generation of bioelectronics systems. Although neurostimulation has seen a history of successful chronic applications in humans, peripheral nerve recording in humans chronically remains a challenge. Multi-contact nerve cuff electrode configurations have the potential to improve recording selectivity.

Classification of naturally evoked compound action potentials in peripheral nerve spatiotemporal recordings.

Peripheral neural signals have the potential to provide the necessary motor, sensory or autonomic information for robust control in many neuroprosthetic and neuromodulation applications. However, developing methods to recover information encoded in these signals is a significant challenge. We introduce the idea of using spatiotemporal signatures extracted from multi-contact nerve cuff electrode recordings to classify naturally evoked compound action potentials (CAP).

The Impact of Anisotropy on the Accuracy of Conductivity Imaging: A Quantitative Validation Study.

We present a quantitative validation study to assess the accuracy of low-frequency conductivity imaging methods, based on a testing current measured using Current Density Imaging (CDI). We tested the proposed procedure to study the influence of tissue anisotropy on the accuracy of conductivity reconstruction methods, using a finite element model of anisotropic brain tissue. Simulations were carried out for three different levels of tissue anisotropy to compare the results obtained by our recently developed anisotropic conductivity method with those obtained by our well-established conductivity method that assumes isotropic conductivity.

Use of spatiotemporal templates for pathway discrimination in peripheral nerve recordings: a simulation study.

Objective: Extraction of information from the peripheral nervous system can provide control signals in neuroprosthetic applications. However, the ability to selectively record from different pathways within peripheral nerves is limited. We investigated the integration of spatial and temporal information for pathway discrimination in peripheral nerves using measurements from a multi-contact nerve cuff electrode.

Experimental implementation of a new method of imaging anisotropic electric conductivities.

This paper presents the first experiment of imaging anisotropic impedance using a novel technique called Diffusion Tensor Current Density Impedance Imaging (DTCD-II). A biological anisotropic tissue phantom was constructed and an experimental implementation of the new method was performed. The results show that DT-CD-II is an effective way of non-invasively measuring anisotropic conductivity in biological media.

Polar decomposition radio-frequency current density imaging.

Polar Decomposition Radio-frequency Current Density Imaging (PD-RFCDI) is an imaging technique that non-invasively measures RF current density components inside a sample using MRI. Previous PD-RFCDI implementations suffer from the strict constraint on the amount of applied current as well as severe interference from the unwanted induced current. This work proposes solutions to both problems which successfully remove the current constraints of PD-RFCDI.

Radio-frequency current density imaging based on a 180 (°) sample rotation with feasibility study of full current density vector reconstruction.

Radio-frequency current density imaging (RF-CDI) is a technique that noninvasively measures current density distributions at the Larmor frequency utilizing magnetic resonance imaging. Previously implemented RF-CDI methods reconstruct the applied current density component J(z) along the static magnetic field of the imager [(B)\vec](0) (the z direction) based on the assumption that the z-directional change of the magnetic field component H(z) can be ignored compared to J(z). However, this condition may be easily violated in biomedical applications.

Multislice radio-frequency current density imaging.

Radio-frequency current density imaging (RF-CDI) is an imaging technique that noninvasively measures current density distribution at the Larmor frequency utilizing magnetic resonance imaging (MRI). Previously implemented RF-CDI techniques were only able to image a single slice transverse to the static magnetic field B(0) . This paper describes the first realization of a multislice RF-CDI sequence on a 1.

Current density impedance imaging.

Current density impedance imaging (CDII) is a new impedance imaging technique that can noninvasively measure the conductivity distribution inside a medium. It utilizes current density vector measurements which can be made using a magnetic resonance imager (MRI) (Scott , 1991). CDII is based on a simple mathematical expression for inverted Delta sigma / sigma = inverted Delta ln sigma, the gradient of the logarithm of the conductivity sigma, at each point in a region where two current density vectors J1 and J2 have been measured and J1 x J2 not equal 0.

Comparison of current densities measured in a pig heart during states of ventricular fibrillation and post-mortem for different defibrillation electrode positions.

Current density imaging (CDI) is an MRI technique used to quantitatively measure current density vectors in biological tissue. A fast CDI sequence was developed that can image the whole body of a 4 kg pig in about 15 minutes. A state of ventricular fibrillation (VF) can be sustained for nearly 30 minutes allowing two complete CDI scans of the same subject.

Noise analysis for multi-slice radio frequency current density imaging.

Radio frequency current density imaging (RF-CDI) is an imaging technique that measures current density distribution at the Larmor frequency utilizing magnetic resonance imaging (MRI). The multi-slice RF-CDI sequence has extended the ability of RF-CDI to image multiple slices and thus has enhanced its capacity for biomedical applications. In this paper, the influence of MRI random noise on the sensitivity of multi-slice RF-CDI measurement is studied.