Biological Signals Acquisition

Artifacts are elements that appear in an experimental result, but are not actually characteristic of the actual entity being studied. In physiological signal acquisition, they are introduced from extraneous sources such as electrical or mechanical interference, or incorrect experimental protocol on the part of experimenter or subject. Here we will introduce artifacts by having the subject blink and by tapping on the electrodes.

A) Blinks: The subject fixates on a nearby object, and then blinks several times.

B) Taps: The subject fixates on a nearby object. This time a partner moves the electrode leads around and taps gently on the electrodes themselves.

Results

Taps

Comments: Evidently artifacts can interfere with the correct interpretation of a physiological signal. The frequency content of artifacts is similar to that of the actual physiological signals being recorded. For this reason, it is best to prevent artifacts during the course of an experiment, rather than attempt to remove them afterwards.

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