At any moment, each of these specialized brain neurons might be receiving multiple messages from multiple sources, but is only selectively responding to certain information about the timing or frequency of the impulses it is receiving. Related Stories.
Methods for measuring sympathetic nervous system activity. Heart rate variability (HRV), the beat-to-beat variation in heart rate, is an indirect method of measuring autonomic nervous system activity, with contributions from both the sympathetic and parasympathetic nervous systems.ine electrodes are used to record 'bursts' of activity from multiple or single afferent and efferent nerve axons in the skin and muscle. The common peroneal nerve is typically chosen for this method (because it is easily accessible) and measures the efferent postganglionic muscle sympathetic nerve activity (MSNA).
Seals DR, Victor RG. Recent investigations using direct (microneurographic) recordings of MSNA have provided a substantial amount of new information on the regulation of sympathetic nervous system control of nonactive skeletal muscle blood flow during exercise in humans.he muscle metaboreflex (muscle chemoreflex) is the primary-mechanism by which MSNA is stimulated during small-muscle, isometric exercise in humans. In contrast, central command has a relatively weak influence on MSNA during this type of exercise. 5.