title: Influence of different preamplifier bandpass cutoff frequencies on the basic pattern of sympathetic nerve discharge.
abstract: Autospectral analysis reveals that most of the power in sympathetic nerve discharge (SND) is contained between 1 and 10 Hz in anesthetized animals. The synchronized discharge bursts of the fibers comprising sympathetic nerves are usually recorded after capacity-coupled preamplification with a bandpass of 1-1000 Hz. However, cardiac- and respiratory-related movement artifacts can adversely affect the signal when this wide bandpass (1-1000 Hz) is used. To eliminate the influence of movement artifacts on the basic pattern of SND, we have routed the output of a preamplifier (bandpass 30-1000 Hz) through a frequency analyzer which measures the frequency of spike discharges exceeding a threshold voltage. After the impulses are rectified and integrated a smooth envelope of the synchronized sympathetic nerve discharge bursts is produced. The following observations have been made: 1) The autospectra of SND constructed after either wide-band preamplification or 30-1000 Hz using the frequency analyzer are similar and 2) Narrow-band preamplification (30-1000 Hz) eliminates movement-related artifacts which adversely influence the sympathetic nerve signal. These results indicate that the basic pattern of SND can be faithfully recorded after narrow-band preamplification which eliminates potential movement-related artifacts.
authors.affiliation: Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan 66506.
authors.forename: M J
authors.initials: MJ
authors.lastname: Kenney
authors.forename: M R
authors.initials: MR
authors.lastname: Fedde
mesh_terms: D000200:Action Potentials; D000818:Animals; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012815:Signal Processing, Computer-Assisted; D013564:Sympathetic Nervous System / Q000502:physiology*