Classification of stance and swing gait states during treadmill walking from non-invasive scalp electroencephalographic (EEG) signals

In Contreras-Vidal and colleagues have shown the feasibility of inferring the linear and angular kinematics of treadmill walking from scalp EEG. Here, we apply a discrete approach to the same problem of decoding the human gait. By reducing the gait process to a mere succession of Stance and Swing phases for each foot, the average decoding accuracy reached 93.71%. This is sufficient to design a gait descriptor that relies only on this classification of two possible states for each foot over time as input, which could complement the model-based continuous decoding method that lacks in some aspects (foot placement at landing, weight acceptance, etc.). A final implementation of this method could be used in a powered exoskeleton to help impaired people regain walking capability

Neuroscience, Ethics, and National Security: The State of the Art

Military involvement and research in neuroscience generates unique ethical, legal, and social issues that require careful elucidation and consideration in order to align the potentially conflicting needs of national defense, public interest, and scientific progress

Non-Invasive Brain-to-Brain Interface (BBI): Establishing Functional Links between Two Brains

Transcranial focused ultrasound (FUS) is capable of modulating the neural activity of specific brain regions, with a potential role as a non-invasive computer-to-brain interface (CBI). In conjunction with the use of brain-to-computer interface (BCI) techniques that translate brain function to generate computer commands, we investigated the feasibility of using the FUS-based CBI to non-invasively establish a functional link between the brains of different species (i.e. human and Sprague-Dawley rat), thus creating a brain-to-brain interface (BBI). The implementation was aimed to non-invasively translate the human volunteer's intention to stimulate a rat's brain motor area that is responsible for the tail movement. The volunteer initiated the intention by looking at a strobe light flicker on a computer display, and the degree of synchronization in the electroencephalographic steady-state-visual-evoked-potentials (SSVEP) with respect to the strobe frequency was analyzed using a computer. Increased signal amplitude in the SSVEP, indicating the volunteer's intention, triggered the delivery of a burst-mode FUS (350 kHz ultrasound frequency, tone burst duration of 0.5 ms, pulse repetition frequency of 1 kHz, given for 300 msec duration) to excite the motor area of an anesthetized rat transcranially. The successful excitation subsequently elicited the tail movement, which was detected by a motion sensor. The interface was achieved at 94.0 +/- 3.0% accuracy, with a time delay of 1.59 +/- 1.07 sec from the thought-initiation to the creation of the tail movement. Our results demonstrate the feasibility of a computer-mediated BBI that links central neural functions between two biological entities, which may confer unexplored opportunities in the study of neuroscience with potential implications for therapeutic applications.open12

The Use of Modified Deconvolution Averaging Algorithm for the Analysis of Auditory Evoked Activity

Continuous Loop Averaging Deconvolution (CLAD) is a recently developed mathematical theory and algorithm that allows to deconvolve averaged electrophysiological signals obtained at high stimulation (Delgado and Özdamar (2004) [1]). It assumes that the individual unit responses are linearly combined to form quasi-steady state responses. One limitation of this algorithm is related to the fact that the length of the recording window has to be equivalent to the duration of the response. In this study, we have developed a modified deconvolution averaging algorithm to derive deconvolved responses when the length of the recording is longer than the duration of the response. The algorithm uses the Least Mean Square (LMS) optimization method to find the deconvolved recording that best fits the acquired data. The method has been applied to study the evoked activity in 40 Hz auditory responses

First results of the novel photon beam position monitor for undulator beamlines of Elettra RID G-7348-2011

The latest generation SR sources have severe constraints for the stability of the delivered radiation. The high brightness beamlines using undulator radiation are most sensitive to electron beam oscillations. Therefore, photon beam position monitors for undulator radiation are being built as detectors of beam movement and as references for feedback systems. A significant part of the radiation coming from the upstream and downstream dipoles is superimposed on the undulator radiation. A novel detector, incorporating photoelectron analysers, has been developed at Elettra. It can be tuned to the working energy of the undulator from few eV to some keV, the active elements intercepting the tails of the photon distribution. A prototype has been developed for the vertical photon beam position monitoring, and a complete set of characterisation measurements has been performed down to the lowest photon energies of the undulator peak. A description of the detector and its features are presented along with the commissioning results. (C) 2001 Elsevier Science B.V. All rights reserved