Search PubMedSearch

PubMed · 7582328

A high-resolution large array (HRLA) surface EMG system.

Abstract

A high-resolution large-array (HRLA) SEMG system comprising 256 separate channels has been developed. SEMG signals are detected by a "bracelet" active electrode array connected to a stack of newly designed biopotential instrumentation amplifiers. A stand-alone data logger acquires and stores the array EMG activity at high sampling rates. A RISC multiprocessor network supports computationally-intensive array signal processing and analysis algorithms. In addition, an improved optoelectronic system for the measurement of human body kinematics has been associated to the HRLA SEMG system to provide the related mechanical characteristics of muscle activity. Analysis results demonstrate that high-resolution muscle fibre conduction velocity histograms can be obtained even from skeletal muscles in which a large number of motor units are simultaneously activated.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

D Prutchi. 1995. A high-resolution large array (HRLA) surface EMG system.. https://doi.org/10.1016/1350-4533(94)00016-3

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Blockade of action potential activity alters initial arborization of thalamic axons within cortical layer 4.

In the formation of connections during the development of the nervous system, it is generally accepted that there is an early phase not requiring neural activity and a later activity-dependent phase. The initial processes of axonal pathfinding and target selection are not thought to require neural activity, whereas the later fine-tuning of connections into their final adult patterns does. We report an apparent exception to this rule in which action potential activity seems to be required very early in development for thalamic axons to form appropriate patterns of terminal arborizations with their ultimate target neurons in layer 4 of the cerebral cortex. Blockade of sodium action potentials during the 2-week fetal period when visual thalamic axons initially grow into the primary visual cortex in cats prevents the normally occurring branching of lateral geniculate nucleus axons within layer 4. This observation implies a role for action-potential activity in cerebral cortical development far earlier than previously suspected, weeks before eye-opening and the onset of the well-known process of activity-dependent reorganization of axonal terminal arbors that leads to the formation of ocular dominance columns.

Action Potentials

Concerted signaling by retinal ganglion cells.

To analyze the rules that govern communication between eye and brain, visual responses were recorded from an intact salamander retina. Parallel observation of many retinal ganglion cells with a microelectrode array showed that nearby neurons often fired synchronously, with spike delays of less than 10 milliseconds. The frequency of such synchronous spikes exceeded the correlation expected from a shared visual stimulus up to 20-fold. Synchronous firing persisted under a variety of visual stimuli and accounted for the majority of action potentials recorded. Analysis of receptive fields showed that concerted spikes encoded information not carried by individual cells; they may represent symbols in a multineuronal code for vision.

Action Potentials