1. BE301
BE LAB 1
DR. JULIAN LIPPMANN
SHORT TERM MEMORY TEST EXPERIMENT
FINAL PROJECT REPORT
MEAGAN BRANCH
RACHEL LIM
AN VAN TRAN
RANDOLPH VIGILANCE
GROUP 202

2. Abstract
The purpose of this study was to test the efficacy of various scenarios on the beta and
gamma waveforms conducted from the brain, as well as their correlation to short-term
memory. More specifically, this study assessed the effect of meditation and caffeine on the
waveforms generated from an electroencephalogram (EEG) and short-term memory. We
used the beta and gamma waves, from the EEG data collected to examine how caffeine and
relaxation affect subjects’ brain rhythms. From there, we analyzed the results of the
memory questionnaires, along with data collected from brain rhythms, and identified the
positives and/or negatives of the stimulants on short-term memory. As the result, the
meditation helped to improve memory, however caffeine had the opposite effect.
Moreover, the EEG signals collected from each subjects were not accurate due to many
internal noises from the subjects.
1.0 Introduction & Theory
1.1 Brain Physiology
The brain can be understood as an extremely complex computer that undergoes thousands of
processes every minute to regulate and control the body. The human brain, in particular, is one of
the most complex living structures in the world. Memory is the brain’s hard drive, or its ability to
store information that it has gathered. Short-term memory (STM), more specifically, is the brain’s
capacity to store information in a readily usable form for a small duration of time [1]. The temporal
lobe of the brain is the structure that rules, mostly, over memory in humans and it consists of the
hippocampus, amygdala, and several hippocampal regions. The hippocampi, (there are two since
there is a lobe on the left and right of the brain), are essential in the storage of information [2].
Neurons are brain cells and they produce the electrical signals that are collected from the EEG tests.
These bio signals are created from the synapses produced in the interactions between neurons and
are always occurring as the brain continues to function. Each neuron has several thousand synaptic
connections with other neurons. In electrical synapses, there is a rapid exchange of signals between
the axon terminal of the axon of one neuron and the dendrites of the cell body of another neuron
[3]. Figure 1 shows a model of a neuron.

3. Figure 1: A Simple Model of a Neuron. At the axon terminal button, electrical signals are sent to a
neighboring neuron’s dendrite. This occurrence is called a synapse. The synaptic cleft is the junction
between the axon terminal button and dendrite, in which the exchange of signals occurs [4].
1.2 Beta Wave and Function
The Beta rhythm has a frequency of around 14-30 Hz and generally has a low amplitude. This low
amplitude is the result of an activated cortex and is seen in normal waking consciousness. Beta
rhythms are found most during active concentration and thinking and are also mainly found at the
front of the brain [5].
1.3 Gamma Wave and Function
The Gamma rhythm has a frequency greater than 30 Hz, generally from 30-60 Hz, the fastest
waveform found in the brain. They are related to cognition, information processing, attention, and
memory. Gamma waves have been found to have a direct connection to long and short-term
memory. Most low-voltage gamma rhythms are found in the frontal lobe of the brain [6]. It is
found that the generation of gamma rhythms is due to the activation of fast-spiking interneurons in
the cerebral cortex [7].
1.4 Electroencephalography (EEG)
The Electroencephalogram (EEG) is a noninvasive clinical tool in which electrodes are attached to
the human scalp to detect the electrical signals being produced from the brain. EEG is often used to
better understand the human brain as well as for diagnosis of brain disturbances and disorders
such as epilepsy, sleep disorders, and dementia. The amplitude of the EEG signal relates to the
synchronous excitation of a group of neurons. The amplitude is produced by adding up the signals

4. produced from the neurons. When the amplitude of the waves is high, this represents drowsiness
or deep sleep. A large amplitude represents an active brain [5].
1.5 Effect of Meditation on Brain
Multiple studies have shown that there is a correlation between meditation and increased gamma
wave activity. A study conducted by Richard Davidson, a neuroscientist at W.M. Keck Laboratory
for Functional Brain Imaging and Behavior, tested the idea that frequent meditation could increase
gamma waves in the brain. In this experiment, 8 of the Dalai Lama’s most accomplished
practitioners (monks) and 10 student volunteers, whom had never practiced meditation before,
were studied using an EEG. Both groups were asked to meditate and the results showed that the
gamma activity in the monks was more significant. They seemed to have more controlled and
powerful gamma waves. Additionally, the highest concentration and activity of gamma brainwaves
were found in the left frontal lobe [8]. This experiment showed that meditation could positively
impose changes on the brain in the short term.
1.6 Effect of Caffeine on Brain
Caffeine is a naturally occurring, psychoactive drug that causes the speeding up of the nervous
system. It can be found in seeds, nuts, leaves, and berries. It takes the body about four hours to
digest about half of a given dosage. It can take as low as five minutes for the caffeine to take effect
on the body and it takes about 30 minutes for the caffeine to take maximum effect.
Regular use of caffeine can create an addiction in the form of a physical dependency on the drug.
Normal symptoms will become evident after about 18 to 24 hours of a person’s last consumption of
it. These symptoms include headaches, exhaustion, and irritability. Long-term consumption of high
doses of caffeine, which is equivalent to having a daily dose of caffeine that exceeds 600 mg, can be
dangerous as it can cause irregular heartbeat, restlessness, and anxiety [9].
A recent study on caffeine’s effect on memory was done by scientists at Johns Hopkins University
(10), in which it was found that caffeine improves “memory consolidation in humans.” The study
indicated that although caffeine did improve the subject’s ability to organize and keep the
information, it did not help memory retrieval nor was there any conclusive evidence of improving
long-term memory capacity.
2.0 Experimental Goals
The goal of this experiment was to investigate a way to improve short-term memory on 6
college students. The purpose is to measure how environmental factors affect short-term
memory by observing the relationship between brain waves and memory. We wanted to
see if short-term memory is improved or weakened due to the use of certain stimulants.
The two stimulants we tested were the consumption of caffeine and completing a 15-
minute meditation.
Before conducting the experiment we hypothesized that meditation will increase the
amplitude and frequency of brain waves, as well as provide better short-term memory

5. results. We also hypothesized that caffeine will increase the amplitude and frequency of
brain waves, but would not improve memory.
3.0 Materials and Methods
3.1 Set Up
3.1.1 Materials
2 BIOPAC electrode lead sets (SS2L), 4 small electrodes, 2 standard electrodes, conductive
gel, Lycra® swim cap, data acquisition unit MP36, Laptop, BSL Pro software, headband,
small (10 oz) Tim Hortons coffee, headphones and 16 recorded lists.
3.1.2 Recorded Lists
In order to conduct the memory test, 16 lists were recorded. Each list was comprised of 10
objects of a similar category. These lists were recorded on an iPhone using voice memo. In
order to ensure continuity throughout the lists, the same speaker recorded them all. Each
recording fell into the range of 22-25 seconds and contained categories that would be
familiar to every subject participating in the study. Figure 2 shows the lists we used during
this experiment.

6. Figure 2: Lists of Objects The figure above shows the recorded lists that were used in the
experiment.
3.1.3 Electrode Placement
Six electrodes, four small and two standard, were used on each subject. In order to find the
optimum electrode placement, the electrode checker was used when placing the electrodes.
Two electrode lead sets were used for each subject. The electrode lead sets were plugged
into CH1 and CH2 on the MP36. CH1 corresponded to the subjects right side and CH2
corresponded to the subjects left side. Hair was moved away from the scalp to make a clear
space for the electrode adhesion area. A sufficient amount of electrode gel was added to
the small electrodes. One small electrode was connected to the Red Lead and was placed
on the forehead, directly above the eye. This was used as the positive electrode. Another
small electrode was connected to the White Lead (negative electrode), and was placed 2-3
inches behind the positive electrode. A standard electrode connected to the Black Lead
(ground electrode) ,was placed on the neck behind the earlobe. This procedure of
electrode connection was done on both right and left sides of the subject. Pressure was
applied to each electrode and electrodes were held in place while the swim cap was placed
on the head to secure the electrodes in place. To further ensure the placement of the

7. electrodes, a headband was placed over the swim cap. The subject was asked to remain
seated in a comfortable position throughout the duration of the experiment.
3.1.4 BIOPAC Channels
Data collection channels were set up for Channel 1 and 2 using the predetermined
standards for EEG testing. Channel 1 corresponded to the subjects’ right side and Channel
2 corresponded to the subjects left side. The data collected for each side of the brain
included the Beta and Gamma waveforms sent from the subjects’ brain. In order to set up a
channel to collect the Gamma waves, the frequency range of the Theta Channel was
changed from 30 to 60 Hz. The label of the Theta Channel was then renamed to be Gamma.
3.2 Characterization
3.2.1 Scenarios
Each session was divided up into three scenarios:
I. Control
Subject remained relaxed with eyes closed throughout the experiment.
I. Meditation
Subject completed a 15 minute guided meditation and then immediately ran
through the following procedure.
I. Caffeine
Subject consumed a 10 oz, small cup of Tim Hortons black coffee 20 minutes prior to
completing the following procedure. According to the Tim Hortons official
nutritional information, the 10 oz black coffee contained 110 mg of caffeine [9].
3.2.2 Segments
The following procedure was followed for each of the scenarios. Each scenario was divided
into 3 segments:
I. Listening
II. Thinking
III. Response
Each segment was marked by a label (listening, thinking and response) to keep track of the
data collected.

8. 3.3 Procedure
3.3.1 Pre-Data Collection
Before the data was taken, the electrode checker was conducted for each channel to make
sure optimum signal was picked up by the electrodes.
When the signals were strong the following was carried out:
I. Subjects remained relaxed with eyes close for the duration of each segment.
II. The EEG BIOPac Software Program was up and running.
III. The subject was prompted to open and close his/her eyes. This test was run for 60
seconds.
IV. The EEG was stopped.
V. The subject put in a pair of headphones and the volume was adjusted for comfort.
VI. A practice list was completed as a trial to ensure the subject had a good
understanding of the experiment.
3.3.2 Data Collection
For each experiment, a director was appointed to ensure that the data collection ran
smoothly.
I. Listening Segment
A. The director signaled the recorder to start the EEG at the same time the list
recording started.
B. Subject listened to a recording of 10 objects.
II. Thinking segment
A. At the end of the recording, the director signaled recorder to mark the start
of the thinking segment.
B. The subject had 15 seconds to think about the recording
III. Response segment
A. After 15 seconds, the director signaled the recorder to mark the start of the
response segment.
B. The director asked the subject 10 Yes or No questions.
C. At the same time, the recorder placed a marker when the subject responded.
D. Based on the subject’s response, the answer was recorded on the response
sheet.
Segments above were conducted for the same way for all 3 scenarios; control, meditation
and caffeine.

9. 3.4 Data Analysis
During each scenario, the raw Beta and Gamma waveforms were recorded. The amplitude
and frequency was recorded in Hz for the waves. From the data obtained, the waveforms
were analyzed in detail.
4.0 Results and Discussion
4.1 Error Analysis
Throughout the experiment, there were certain sources of error; therefore measures were
taken to reduce the effect of these errors. Prior to data acquisition, the electrode checker in
the MP36 box verified the placement of electrodes. This allowed us to accurately place the
electrodes on the scalp to get the best signal possible. Poor electrode placement could
result in little to no signal and only noise. Figure 3 shows the electrode checker of subject
6. This process was completed on both sides of the head to ensure best placement of
electrodes, as well as symmetry. Throughout the duration of the experiment, the subjects
eyes remained closed and they remained relaxed to help reduce noise recorded on the EEG.
Throughout the experiment, the recorder placed markers whenever a subject would move
or speak. This was used during data analysis to ensure that only the raw EEG was taken
during brain waves, and not during noise. This ensured that there would not be any
outliers during analysis. Due to a headache midway through testing, the data for subject 4
was removed and not used during data analysis.
Figure 3: This figure shows the electrode check of subject 7.
4.2 Memory Test Results
Based on the experiment that was carried out, along side with EEG data collection, we had
the subjects’ answer 10 Yes/No questions. Each scenario had 5 lists, for a total of 15. The
subject responses were tabulated and graphed as Figure 4. From the figure, we see that in

10. the three scenarios, the control had 74.57% correct responses, meditation had 77.29%
correct responses, and caffeine had 72.00% correct responses. Hence, the meditation
scenario has the highest significant value compared to the control scenario followed by
caffeine scenario.
We hypothesized that meditation would have a more positive outcome on a subject’s short-
term memory retention capabilities. That is true based on the experiment that was carried
out. Figure 5 shows that meditation has a positive outcome when compared to the intake of
caffeine. A percentage difference of 2.72% increases for the meditation scenario. On the
other hand, with caffeine consumed, the overall percentage of difference from the
controlled scenario shows a decrease of 2.57%.
Therefore, short-term memory is improved with meditation; while of the consumption of
caffeine decreases short term memory.
Figure 4: The figure shows the overall percentages of all subject responses in three different
scenarios; Control, Meditation and Caffeine. Meditation shows the highest percentage of
accurate responses, followed by Control and then, Caffeine.

11. Figure 5: The figure shows that meditation improves short-term memory by 2.72% while
caffeine degrades short-term memory by 2.57%. This is when compared to the controlled
scenario.
4.3 Listening Segment
At the beginning of each scenario, the subject is required to listen to an audio recording.
While the subject listens to the recording, the brain is active and waves were fired. The data
of gamma and beta waves were taken into account. Based on Figure 6 the average values of
the beta waves for all subjects were 1.8 0.2 V, 1.5 0.3 V and 1.4 0.3 V representing control,
meditation and caffeine respectively. On the other hand, the average values for gamma
waves for the control, meditation and caffeine of all subjects were 0.9 0.1 V, 0.7 0.1 V and
0.6 0.2 V respectively. The figures show that when compared to the control, both thinking
and listening have smaller amplitude than the controlled. There are two main reasons for
the decrease in amplitude over three scenarios. First, the guided meditation might not help
the subjects stays relax during 15 minutes. In addition, all subjects that participated in our
experiment did not have any experience with meditation, so they may have felt tired,
experienced a headache, or felt uncomfortable. Moreover, 20 minutes might not enough
time for body to absorb caffeine and depending on how often the subjects consume coffee
daily, the results might be affected.

12. Figure 6: The figure shows that during listening segment, both gamma and beta waves
decrease in meditation and caffeine conditions comparing to control state. However, the
amplitude of gamma wave does not show clearly the differences.
4.4 Thinking Segment
During this period of the experiment, the subjects had 15 seconds to consolidate and think
about the list of information they had just listened to. The graph below depicts the
amplitudes of the voltages of both beta and gamma waves at each stimulus. Voltage
amplitudes were lower than the control when the subject was exposed to the stimuli in
both waveforms. The voltage amplitudes represent the amount of signal that the electrode
collected. Therefore, beta and gamma waves in the brain decreased due to the effect of
meditation and caffeine. However, there was not a significant difference between the
results of the meditation and caffeine. Voltage results between subjects undergoing
meditation and caffeine were very close. Based on Figure 7, the amplitudes of beta waves
are 1.8 0.2 V, 1.4 0.3 V and 1.3 0.3 V respectively for control, meditation and caffeine. On
the other hand, the gamma waves amplitude values are 0.8 0.1 V, 0.7 0.1 V and 0.6 0.2 V,
with respective to the gamma control, meditation and caffeine scenarios. The difference
between the amplitude of the beta wave (more than 1.3 uV) and gamma wave (less than 0.8
uV) show that there is a significant difference between the two waveforms.

13. The thinking and listening are not much of a different
Figure 7: The figure shows the amplitude differences in 3 conditions of beta and gamma
waves. The amplitudes in the voltages recorded in the brain were lower when the subjects
consumed coffee (caffeine) and underwent meditation during thinking segment.
4.5 Response Segment
The response period was the time in which the subjects answered the given questions
about what had heard. When analyzing the data, we neglected the spike in amplitudes
marked when the subject spoke or moved. The reason is those amplitudes are not the brain
signals, but instead noise generate from the subjects movement. The amplitudes still
decrease after the subjects went through three scenarios: control, meditation, and caffeine.
The beta and gamma waves are separated so that it is easier to view as in Figure 8. For the
control, meditation and caffeine beta amplitudes, the values are 2.2 0.4 V, 1.7 0.4 V and 1.7
0.4 V respectively. The values for gamma are 1.2 0.3 V, 1.0 0.3 V and 0.9 0.2 V with respect
to control, meditation and caffeine. The overall average for control is higher than the
meditation and caffeine for amplitude of beta and likewise for gamma. However, the
uncertainty for those waves are high (0.4 V and 0.3 V) and it makes the amplitudes overlap
over three scenarios. The reason for this overlapping is the data that we collected contains
many noises. Those noises are internal noise and can be considered as body movement,
mouth movement when answered the questions, especially the eye movement. The
subjects moved their eyes even though they were required to close throughout the
experiment.

14. Figure 8: The figure shows the amplitude differences between 3 conditions of beta and gamma
waves during response segment. There are a lot of noise during this period causing the
differences are not clear.
5.0 Future Direction
If this experiment were to be conducted again, here are some changes that we would make
to reduce error and increase the effectiveness of results. First of all, we would have the
subjects test for a shorter period of time. During this experiment subjects sat through
about 2 hours of testing. We would like to reduce the test time to about 30 to 60 minutes
per session. This will reduce the fatigue per subjects. Additionally, we would want the
subjects to test over a longer period of time. For this test each subject only tested once, we
hope to test over the course of one month. We also want the subject to practice meditation
throughout the course of the experiment. All of the subjects had never experienced
meditation before and therefore may have not benefited from its effects. Having the
subjects practice meditation every day for a month throughout the duration of testing
would hopefully show a positive trend. The more experience the subjects have with
meditation, the higher and more controlled their gamma waves are. We would also change
the method of the lists. The difficulty of lists would be increased and we would also
randomize the lists between subjects. This will decrease the possibility that the 5 lists for
caffeine was harder than the 5 lists for control and meditation and vice versa. We would
also like to increase the time after drinking coffee to 30 minutes, as we found through
research that it takes 30 minutes to take full effect. Finally, we would like to use better
EEG equipment. For this experiment we only used 6 electrodes on the scalp. With better
equipment we could get a better signal from the brain and have greater co9ntact on the
scalp.

15. 6.0 Conclusion
In conclusion, the result of the memory test shows that after meditation the subjects are
more accurate when answering questions compared to the control. After drinking a cup of
coffee, the subjects had a lower performance on the memory test compared to the control.
This led us to the conclusion that meditation increased short-term memory while caffeine
consumption decreased it. This finding is consistent with what we originally hypothesized.
The amplitudes of beta and gamma waves decrease due to the meditation and caffeine
stimulants. However, there is not a significant difference between the listening and
thinking segments. In addition, we found that the results from the EEG were not as
accurate as we originally expected. Therefore it was difficult to see any connection
between brainwave activity and the accuracy of the memory test.

16. References
[1] J.K. Author. (2013, August 28). DefinitionofShort-TermMemory [Online]. Available:
http://www.medicinenet.com/script/main/art.asp?articlekey=7142
[2] S. Zola-Morgan. (1991, Sep 20). Themedialtemporallobesystem. [Online]. Available:
http://www.ncbi.nlm.nih.gov/pubmed/1896849
[3] J.Kimball. “Synapses” Internet:
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/Synapses.html#electrical_synapses ,
May 6, 2013 [Nov.29, 2014]
[4] [4] J.K. Author. (2013, October11). Neuron[Online]. Available: http://thebrainbank.org.uk/wp-
content/uploads/2012/08/neuron.jpg [Nov. 29, 2014]
[5] L. Sornmo, P. Laguna. (2005, June 15). Bioelectrical SignalProcessingin Cardiacand Neurological
Applications.[On-line].
Available:https://www.dropbox.com/sh/3bjr1r8ki51okvi/AADukyXfEwLvTJobeCw_W4Kya/Readi
ng/EEG/Sornmo%20Bioelect%20Signal%20Processes%20Chp%202.pdf?dl=0 [Nov. 24, 2014].
[6] J.R. Hughes. (2008, July).“Gamma, fast, and ultrafast wavesof the brain: Their relationships
with epilepsy and behavior.” ScienceDirect.[On-line]. Availible:
http://www.sciencedirect.com/science/article/pii/S1525505008000127 [Nov. 25, 2014].
[7] P.R. Reiner. “Mediation on Demand.”
Internet:http://www.scientificamerican.com/article/meditation-on-demand/ [Nov. 28, 2014].
[8] M. Kaufman. “Meditation Gives Brain a Charge, Study Finds.” Internet:
http://www.washingtonpost.com/wp-dyn/articles/A43006-2005Jan2.html [Nov. 28, 2014].
[9] J.K. Author. (2013). Caffeine [Online]. Available:
http://www.camh.ca/en/hospital/health_information/a_z_mental_health_and_addiction_informati
on/caffeine/Pages/default.aspx
[10] Sue Hughes. “ Caffeine Enhances Memory Consolidation”. Internet:
http://www.medscape.com/viewarticle/819483[Nov. 25, 2014].
[11] Tim Hortons. “Tim Hortons Caffeine Content.” Internet:
http://www.timhortons.com/ca/en/pdf/CAFFEINE_CONTENT_-_Canada_-_August2014.pdf [Nov.
30, 2014]