Jasmine Hawkins
Dr. M. Khurgel
December 1, 2014
Introduction
In this experiment the electroencephalogram was used to record brain activity during
two different mental tasks: one of them being reading a novel and the other being listening to
the audiobook of the novel. By attaching a pair of electrodes to the scalp the
electroencephalogram can be used to measure the electrical activity changes of the brain. The
way that this works is when the pair of electrodes are attached to the scalp they record the
difference in electrical potential between the two positions of electrodes. A third electrode is
attached behind the ear to be used a reference point of the body’s baseline voltage. Electrodes
normally record these changes at a short distances from neurons that are functioning in that
particular area. As membrane potentials change within a localize areas, highly sensitive
electrodes can sense the neuronal magnetic and electrical fields.
Methods
The objective of the experiment is to examine the differences in brain waves when
comparing listening to an audiobook to reading a book silently. The first step in this experiment
is setting up the computer and the biopac unit. Turn the computer on, and following this plug
the Biopac unit into the computer and plug the electrodes into channel 1 on the biopac unit.
Turn the biopac on and open the biopac software. Attach the electrodes to the scalp of the
subject; keep the electrodes on either the right or left side of the head. Put electrode labeled
VIN+ on the temporal lobe, the electrode labeled VIN- on the occipital lobe. The third electrode
will be placed behind the ear; this electrode is considered the ground electrode. At this point
make are that all electrodes of securely attached on the scalp for accurate and precise results.
Have your subject(s) in a seated position. Give the subject(s) time to relax. Once all these steps
are completed, click on electroencephalography (EEG) I on the opening page of the software.
Be sure to make a file to save all results. After this click calibrate, during this time the subject(s)
should be fully relaxed with eyes open. Once the calibration is completed, check channels to
make sure all rhythms are present. After this step, data recording can begin.
When data recording, there will be two data tables per subject. For this experiment, it is
suggested that three or more subjects are to be used. One data set will be looking at the brain
activity while the person reads for twenty seconds, closes their eyes and relaxes for twenty
seconds, and then re-open their eyes and reads for another twenty seconds. The second set of
data will have the subject listening to the audiobook of the same novel that they read in the
previous trial. The subject will listen to the audiobook for twenty seconds with their eyes open,
they will then close their eyes in silence for twenty seconds, and then re-open their eyes and
listen to the audiobook again for twenty seconds. Once the data had been recorded, the next
step is to analyze the data.
Results
The results show that there is a difference between the tasks that the subjects are
doing; in this case reading and listening to an audiobook. The results also show that there is a
difference between when the subjects are at a resting state compared to when the subject are
doing a task. In both table sets there is a noticeable decrease from when the subjects were
doing a task from when they were at rest. When looking at the difference between the two
tables sets the numbers for electrical activity in listening were extremely higher than when the
subjects read. The possible reason for this is there is more electrical activities between neurons
in order for the information to be integrated and processed for the task to be completed. When
examining neuronal pathways, I found that there are more lobes in the brain associated with
listening causing more neurons to be involved, which results in more electrical activity,
compared to reading which uses less amounts of neurons.
Table Set 1: Neuronal electrical activity for when all subjects were reading a novel and at rest.
Subject 1
Rhythm
Alpha
Beta
Delta
Theta
Rhythm
Subject 2
Alpha
Beta
Delta
Theta
Rhythm
Subject 3
Alpha
Beta
Delta
Theta
CH
Measurement
40 Stddev
41 Stddev
42 Stddev
43 Stddev
Reading
(eyes opened)
7.62018 uV
5.45783 uV
12.74411 uV
10.35544 uV
Resting
(eyes closed)
5.26245 uV
3.33403 uV
12.53787 uV
9.79782 uV
Reading
(eyes opened)
8.83080 uV
6.06414 uV
21.95946 uV
12.91310 uV
CH
Measurement
40 Stddev
41 Stddev
42 Stddev
43 Stddev
CH
Measurement
40 Stddev
41 Stddev
42 Stddev
43 Stddev
Reading
(eyes opened)
2.08328 uV
1.72268 uV
2.87924 uV
2.54082 uV
Reading
(eyes opened
6.22159
5.74305
20.46445
10.80875
Resting
(eyes closed)
1.60963 uV
1.37637 uV
2.02297 uV
0.04999 uV
Resting
(eye closed)
6.11908
5.65482
14.38822
9.35421
Reading
(eyes opened)
1.79515 uV
1.44454 uV
2.60808 uV
2.20463 uV
Reading
(eyes opened)
2.30395 uV
3.56931 uV
6.42410 uV
2.44791 uV
Table Set 2: Neuronal electrical activity during listening to an audiobook and resting in silence.
Subject 1
Rhythm
Subject 2
Alpha
Beta
Delta
Theta
Rhythm
Subject 3
Alpha
Beta
Delta
Theta
Rhythm
Alpha
Beta
Delta
Theta
CH
Measurement
40 Stddev
41 Stddev
42 Stddev
43 Stddev
CH
Measurement
40 Stddev
41 Stddev
42 Stddev
43 Stddev
CH
Measurement
40 Stddev
41 Stddev
42 Stddev
43 Stddev
Listening
(eyes open)
1.86469 uV
1.69949 uV
1.79372 uV
0.04924 uV
Listening
(eyes open)
27.17242 uV
19.97279 uV
46.0995 uV
39.66619 uV
Listening
(eyes open)
120.77961
92.88609
314.36009
180.28289
Resting
(eyes closed)
1.63351 uV
1.36988 uV
1.42596 uV
0.04827 uV
Resting
(eyes closed)
1.45021 uV
1.33165 uV
1.74586 uV
1.56491 uV
Resting
(eyes closed)
64.73548
69.68382
197.15664
102.49887
Listening
(eyes open)
1.52657 uV
1.37242 uV
1.13892 uV
0.04966 uV
Listening
(eyes open)
2.27140 uV
2.25367 uV
2.68915 uV
2.23684 uV
Listening
(eyes open)
11.31299
11.93816
28.03639
14.08952
Discussion and conclusions
Everything within the experiment did not go as planned. It was difficult to get the electrodes to
have complete stick to the subject’s skin and scalp. Timing was another difficult part in the experiment
because it was not exactly twenty seconds each time for each subject. It was also hard to monitor if
during rest, the subjects were actually at rest because they could have been thinking about other things.
These things definitely contributed to the accuracy and precision of our results. There is no doubt that
there is a variance between neuronal activity for reading and listening to the audiobook. This is also the
same for when the subjects were at rest and when they are doing a task. Overall I learned how the
electroencephalogram works with respect to sensing changes in electrical activity at the cellular level.
This exercise helped me see how what we learned in class in used in respect to the medical field and
how the results can verify events happening within the brain.