Abstract: Objective To investigate if it is possible to extract the information of single nerve fiber discharges from multiple fiber discharges of carotid sinus baroreceptors with Spike 2 software and to establish a detailed method. Methods To record the pressure in the carotid sinus and in vitro few fiber discharges of the sinus nerve simultaneously and then to sort all the action potentials by means of Spike 2 software. Results 1 It is necessary to define several template parameters according to the baroreceptors properties. 2 Reliable unit discharges could be extracted with Spike 2 program from the sinus nerve discharges with a high signal-to-noise ratio containing 2-3 units or more 5 units. 3 It should be prudent when analyzing the baroreceptor discharges containing much more units with this program. Conclusion Spike 2 software is suitable for cluster analysis on carotid sinus baroreceptor discharges containing units not more than 5. For an accurate sorting it is a prerequisite to obtain raw records with a fine signal-to-noise ratio and to set up the template parameters pertinently.

Key words: carotid sinus baroreceptor, action potential, single-fiber discharge, clustering analysis, principal component analysis