BSL PRO Lesson H24 - Biopac

Updated 06.10.11
BSL PRO Lesson H24:
Habituation
Abstract
Habituation is the term used to describe the decrease in physiological response with repeated
exposure to a stimulus. Habituation is a fundamental principle in psychophysiology that shows that
repeated presentation of a stimulus leads to reduced response. Response on repeated trials, while
most likely to be reduced, might also be increased, illustrating the fact that habituation is a
probabilistic trend toward decreased response.
Habituation is a very important concept, especially for researchers, because it is a common effect in
psychophysiological recordings. For example, a subject might have less of a response after a few
trials of the same experiment than upon first exposure to that stimulus.
This experiment will test a subject's response level while being exposed to a series of pictures with
one of the pictures being drastically different and repeated five times over the course of the
presentation. The subject should experience habituation and his/her electrodermal response and
heart rate should continually decrease after each exposure to the aberrant image.
Objectives
1. Monitor electrodermal response and heart rate during repeated presentation of a stimulus to
demonstrate reduced response.
2. Illustrate that habituation is a probabilistic trend toward decreased responding.
Equipment
BIOPAC GSR transducer (SS3L)
BIOPAC Hand switch (SS10L)
BIOPAC Disposable Electrodes (EL503)
BIOPAC Electrode Lead Set (SS2L)
BIOPAC Electrode gel (GEL1)
Stimulus Presentation (optional visual stimulation PowerPoint file included)
Computer running Windows 7/Vista/XP or Mac OS X 10.4 – 10.6
Biopac Student Lab PRO software
BIOPAC Data Acquisition Unit (MP36/35/30)
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BSL PRO Lesson H24
Setup
BIOPAC Systems, Inc.
Hardware
1. Plug the GSR transducer into CH 1 on the MP3X unit.
2. Plug electrode lead set into CH 2
3. Plug the hand switch into CH 3 on the MP3X unit.
4. Turn on the MP3X data acquisition unit.
Software
1. Turn on the computer.
2. Launch the BSL PRO software on the host computer.
3. Open the Habituation lab by choosing File menu > Open > choose Files of type: GraphTemplate
(*GTL) > File Name: H24 Habituation.gtl.
In BSL 3.7.7 and higher, the template can be selected in the Startup Wizard by selecting ‘Record a lesson >
BSL PRO’ and choosing H24 from the list.
Subject
GSR Setup
• The template can also be downloaded from the BIOPAC website PRO Lessons page.
1. Fill both cavities of the GSR transducer with gel.
2. Attach the transducer to the Subject’s favored hand as
shown, one band on the middle finger and the other on
the index finger.
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BSL PRO Lesson H24
ECG Setup
BIOPAC Systems, Inc.
1. Place electrodes on the inside of the right wrist and on
inside of both ankles, above ankle bone.
2. Place electrode leads as shown in diagram.
Red - Left ankle
Black (GND) - Right ankle
White - Right Wrist
Running the Experiment
The template is set to display CH 1 GSR, CH 3 Hand switch, and CH 40 Heart Rate. Heart rate is calculated
from the ECG signal, but the CH 2 ECG signal is hidden.
Recorder will press the hand switch to mark when the aberrant picture appears.
Hints for minimizing data error
Wait at least five minutes after attaching the GSR transducer and electrodes so the skin has ample time
to absorb the gel.
For best results, subject should not move and recording should not be stopped between calibration and
the experiment segments.
The subject must avoid excessive extraneous movement.
Press the hand switch every time the clown picture appears (to be used as a time marker).
Remove all jewelry or other metal objects.
Check all cable connections.
Signal Check
1. Position subject approximately 2 feet directly in
front of computer monitor.
2. Click “Start” to begin recording.
3. Have the subject inhale deeply.
4. Review the data after 10-15 seconds, while
continuing to record.
• If CH 1 GSR displays a significant
change, as shown at right, continue
without stopping the recording. If not,
check all connections and repeat.
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BSL PRO Lesson H24
Experiment
BIOPAC Systems, Inc.
Note
This experiment uses a PowerPoint presentation for visual stimulation, but you may use any repeated
stimulus with one or more aberrations.
1. If calibration was successful, continue the recording.
2. Have the subject relax until GSR is stabilized and there is a constant straight line.
• Note: At this point subject should already be sitting in front of monitor, and should be relaxed and
not moving.
3. Once the subject is set, open the H24 PowerPoint presentation.
• When the slideshow is open, the BIOPAC screen will not be visible.
4. Click F5 to begin playing the slideshow (or select View Show from the Slide Show menu).
• Hit the “Esc” key to stop the slide show at any time.
5. Recorder must use the hand switch to indicate when the aberrant picture is presented.
6. At the end of the slideshow, close PowerPoint.
7. Click Stop to end the recording.
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BSL PRO Lesson H24
Data Analysis
BIOPAC Systems, Inc.
You can measure the GSR change on repeated trials, which will likely reduce with each repetition.
Standard Trial Habituation Data Using the BSL PRO
Appendix
GRAPH TEMPLATE SETTINGS
Click here to open a PDF of the graph template file settings. The BSL PRO Graph Template file automatically
establishes the settings shown in the table.
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