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).
a system of efferent dilator nerves distributed only to skeletal muscles; the existence of the system has been verified only in cats and dogs; in other species where it is not present vasodilation is achieved only by relaxation of vasoconstrictor tone. sympathetic nerves. 1. see sympathetic trunk (below).wo long ganglionated nerve strands, one on each side of the vertebral column, extending from the base of the skull to the coccyx. sympathetic trunk ganglia. ganglia situated segmentally along the paired sympathetic trunks beside the vertebral bodies.