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).
Activation of the sympathetic nervous system during an episode of acute pain is known as the âfight or flightâ response. The physiological responses that take place via the sympathetic nervous system and the neuro-endocrine system are numerous and intrinsically linked. noxious stimulus or pain is a stressor that can threaten homeostasis (a steady physiological state). The adaptive response to such a stress involves physiological changes that, in the initial stages, are useful and are also potentially life-saving.