Hi Randy,

Stimulus artifact is the recording of the electrical transient generated by the electrical stimulation which travels at speeds close to the speed of light, much faster than any cellular response to same stimulus. Therefore, stimulus artifacts always appear before any cellular responses. Basically recording electrode is picking this electrical transient (stimulus) which usually last less than a millisecond (0.1 to 0.3 ms), depending on your setting. When you apply an electrical stimulus (voltage or current) that travels either from negative to positive or from positive to negative pol, depending on your selection on the stimulation parameters. If you choose bipolar stimulation it will alternatingly stimulate either negative or positive polarities; in contrast monopolar stimulation will stimulate only in one direction (normal or reverese). If the polarity changes by itself that may be due to the proximity of the negative or positive pol to the recording site (electrode).

best wishes,

Refik

Hi Refik,

Thanks so much for your response, it was really helpful.

Best,

Randy