sympathetic nervous system measurement nerve activity measurement sympathetic nerve activity measurement 2013-01-07T15:40:46Z Any assessment or quantification of the presence and/or amount of recordable electrical energy in a sympathetic nerve, a nerve of the autonomic nervous system that regulates involuntary and automatic reactions, especially to stress. A nerve is any of the cordlike structures that convey impulses between the central nervous system and one or more parts of the body, and that each consist of an outer connective tissue sheath surrounding a bundle of conductive fibers. CMO:0001236 JSmith clinical_measurement_ontology