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Fig 1

Dataq Display; Channel 1 shows a 1 sec timer and channel 4 is a marking signal. Channel 2 shows skin potentials and Channel 3 shows skin conductance levels from the other hand.

METHOD

Apparatus
A Coulbourne bioamplifier & skin conductance module will amplify the signals to be displayed on the Windows 2000 computer.

Procedure

Choose a subject from your group. Use the bi-polar electrode placement as described by the diagram in Andreassi (2000) except place both the electrodes on the palm of the hand instead of the fingers. Place one electrode on the thenar eminence and one on the hypothenar eminence and place the ground on the wrist bone on the back of the hand to which the electrodes are also attached. The thenar eminence is the fleshy part of the palm of the hand right below the thumb. The hypothenar eminence is the area of the palm below the fifth, "pinky" finger. Use double adhesive disks to attach the electrodes to the skin, and follow by wrapping clear office tape around the electrodes and the hand, if necessary, to keep the electrodes from "sweating off". Use a similar electrode placement for the other hand. Make sure to use a jumper for the grounds and not to put two ground electrodes on the subject.

When all electrodes are attached firmly, begin recording do a 2 min baseline measure of readings to see what normal readings for this person are like. Then MARK THE RECORD. Next, tell the subject to count backwards in their heads from 256 to 0 by 17's.

When the subject finishes counting, MARK THE RECORD and record another 2min baseline.

Then review the SPR record to see how skin potential frequencies changed while the subject was counting.

Lab Questions:

1. These are the same electrodes we used for EMG and the same amplifier is used to record SPR. Why aren't we getting EMG?

2. When scoring the SPRs are we dealing with amplitude changes or frequency changes?

3. How do SPR and SCL differ?

REFERENCES

Andreassi, J. L. (2000). Psychophysiology Human Behavior & Physiological Response. Hillsdale, New Jersey: Earlbaum

For Further Reading:

Blake, A.W., Page, M.S., Short, J.W.,Wegner, D.W. (1990). The suppression of exciting thoughts. Journal of Personality and Social Psychology, 58(3), 409-418.

Edwards, S., Mathews, A., Moses, J., Steptoe, A.M. (1990). Aerobic fitness, physical activity, and psychophysiological reactions to mental tasks. Psychophysiology, 27 (3), 264-74.