Available online at:
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J Camosun Psyc Res. (2019). Vol. 1, pp. 20-30.
Submitted April 2019; accepted 3 May 2019.

The effect of fear on brain activity.
Author: Miranda Kohuch*
Supervising Instructor: Michael Pollock, Psyc 215 (“Biological Psychology”)
Department of Psychology, Camosun College, 3100 Foul Bay Road, Victoria, BC, Canada V8P 5J2
*Corresponding author email: mirandakohuch97@gmail.com

ABSTRACT
Generalized Anxiety Disorder (GAD) is a severe pathology that has been known to affect the
functionality of individuals in their everyday lives even when the presence of a non-fearful
stimuli is introduced, however, the effect of anxiety on individuals with GAD is thought to
increase and therefore, effect the functionality more in the presence of fear-provoking stimuli.
The present study first investigated under longitudinal baseline conditions how fear was related
to the brain activity of a Camosun College Psychology student by measuring their prefrontal
(frontal EEG and reinforcement-based decision making), hippocampal (free recall performance),
and amygdala (heart rate) activity while being non-experimentally exposed to different levels of
anxiety-causing stimuli. Correlational analyses revealed that fear was most strongly related to
levels of amygdala (r = 0.36) and hippocampal (r = -0.21) activity. In a second study, in order to
examine if fear plays a casual role upon hippocampal activity, this relationship was
experimentally tested by randomly assigning the participant across days to a high-fear
conditioning (horror movies) versus a low-fear condition (non-horror movies). The results
showed no statistically significant effect of fearful stimuli upon hippocampal activity.
Implication of the study suggest that the experimental level of fear induced within the study was
not great enough to produce an effect upon free recall that was able to be reliably detected.
1. Introduction
Generalized Anxiety Disorder (GAD) is a
severe mental disorder that produces a
global lifetime prevalence of about 2-3%
(Diwadkar et al., 2017) and a lifetime
prevalence in young people of between 6%
to 30% (Mash & Wolfe, 2019). This
pathology is commonly categorized through
a long-term disruption in daily activities due
to the presence of excessive and
uncontrollable worry over many activities or
events (Mash & Wolfe, 2019). Common
symptoms that are seen within individuals
with the disorder are irritability,

concentration difficulties, difficulty
sleeping, and a lack of energy (Mash &
Wolfe, 2019) which can be detrimental to
the daily functioning of individuals with the
disorder to the point where they feel that
they are trapped within the realms of their
anxiety. It has been shown in past research
that individuals with GAD tend to have a
greater difficulty with suppression than
retrieval in memory tasks (Diwadkar et al.,
2017) as well as having to make decisions
based on either receiving a reward or
punishment following the decision made
(White et al., 2017).

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Previous studies conducted have shown
a reduced amount of activity in brain
structures such as the thalamus, cerebellum,
hippocampus, and amygdala in individuals
with GAD when compared to their healthy
counterparts (Diwadkar et al., 2017).
The studies that focus on the cognitive
deficits in individuals with GAD, such as
suppression and retrieval, as well as the
ability to make decisions based on the
presence of a reward or punishment (White
et al., 2017) have found decreased activity in
brain areas that are vital for normal brain
function. With regards to suppression and
retrieval tasks, Diwadkar and colleagues
(2017) proved in their research that,
“…GAD participants were characterized by
more Suppression-than Retrieval-related
hypo-activation…these effects suggested
that GAD confers susceptibility for
processes of memory control…” (p. 46).
Whereas, White and colleagues (2017)
showed in their research that, “…individuals
with generalized anxiety disorder showed
impaired reinforcement-based decision
making…during feedback, they showed a
reduced correlation between PE and BOLD
responses within the ventromedial prefrontal
cortex… [and the] dorsomedial prefrontal
cortex… relative to healthy comparison
subjects.” (p113-114) suggesting that GAD
does have an effect on the ability to make
decisions as well as with suppression and
retrieval of memories.
In the current study, based on the
previously reported decrease in hippocampal
and amygdala activity seen in GAD patients,
it was hypothesized that as fear/anxiety
levels increase, then hippocampal, prefrontal
and amygdala activity would decrease. The
final hypothesis stated that as fear/anxiety
levels increased, reward system activity
would decrease as well. The hypotheses for
the study were based on the previous
research that individuals with GAD

experience under-engagement in brain
regions such as the hippocampus and
amygdala when asked to retrieve
information following a suppression task.
This rationale led to the interest to further
investigate the effect that anxiety/fear has on
the reward system since it had been proven
to cause an effect in the ventromedial and
dorsomedial prefrontal cortices.
2. Methods
2.1 Participants
An individual Psychology student from
Camosun College was recruited to
participate within the current study. The
students current age was 21, and the student
identified as female in terms of their gender.
The participant at the time of these studies
had been diagnosed with General Anxiety
Disorder and was currently taking a
selective serotonin reuptake inhibitor
(SSRI), citalopram at a dosage of 40 mg.
2.2 Materials and Apparatus
The materials used in this experiment
were a 13-inch MacBook Air laptop and the
software PEBL: Psychology Experiment
Building Language, in order for the
participant to complete free recall tests. The
“Non-Horror” films (e.g., Aladdin) and
“Horror” films (e.g., Silent Hill, see Table 3
for full list) were watched on the streaming
service, Netflix, or rented from the iTunes
Store, and watched on an Apple TV on an
approximate screen length of 30-inches. On
plain, white standard printer paper cut into
pieces approximately 1.00cm by 6.00cm, the
names of specific horror movies were
written onto the slips or the term “NonHorror” which indicated the type of film that
was expected to be watched that day. The
pieces of paper were all placed in a small,
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yellow bucket and each slip of paper was
folded in half.
2.3 Procedure
2.3.1 Baseline Study
Each of the four different hypotheses
were tested for a maximum of 12 days, and
the correlations between the independent
variable (fear/anxiety) and the dependent
variables (hippocampal, prefrontal,
amygdalae, and reward system activity)
were recorded in order to find the hypothesis
with the largest negative correlation. The
level of anxiety/fear was determined through
the use of the Pollock Modified-POMS
Scale (Appendix A) and the level of anxiety
was rated on a scale from 0 to 100, where 0
being “Not at all” and 100 being
“Extremely”. The level of fear/anxiety
determined through the use of this scale was
used for all four hypotheses’ daily
fear/anxiety level that would correspond
with the different dependent variables
measured each day. The level of significance
set in this experiment was .05.
The participant was subjected to four
different procedures for the baseline portion
of the study in order to test each of the four
dependent variables. Since the participants
brain activity in the hippocampus, prefrontal
cortex, and amygdala was unable to be
recorded directly from the structure itself, a
series of tasks were performed in order to
gain an indirect measurement of the level of
brain activity within each of the areas. To
test for hippocampal activity, a free recall
test was administered for three trial runs.
The free recall test was used through the
program PEBL (The Psychology
Experiment Building Language) and was
administered in three different trials where
the participant was momentarily shown ten
different words (e.g., SERVE, COSTUME,
BLANKET) that they were expected to

recall once the final word had been
presented on the screen. The values that the
participant recalled correctly were tabulated
up and divided by the total number of words
(thirty) that were presented to the participant
in order to receive an overall percentage that
represented the level of activity that may be
present alongside a certain level of
fear/anxiety. This variable was measured
two-times daily over the span of the 12 days
at different times of the day in hopes to
account for differing anxiety levels, and the
average score from the trials at two different
times of the day were averaged out in order
to find the average recollection rate
corresponding to the daily anxiety level.
When testing the prefrontal and the
amygdalae activity, the participants
underwent different testing methods twicedaily for the 12 days in order to indirectly
measure the activity in these structures. To
determine the activity within the prefrontal
cortex, a MUSE headband was placed along
the participants forehead for one minute of
recording. Under each of the sections,
Alpha_AF7 and Alpha_AF8, the activity
reading at each 10 second mark for one
minute was written down to produce a total
of 6 readings per column. The six values in
each column were then averaged out by
adding them all together and dividing the
value by six, and then the singular values
produced within each column were averaged
together in order to provide a single value
corresponding to prefrontal activity at
different anxiety levels. To test for
amygdalae activity, the heartrate of the
participant was recorded for one minute. The
participant measured their own heartrate by
placing their pointer and middle fingers
along the carotid artery located within the
cervical region. The number that the
participant counted was doubled in order to
account for the second pulse that is not so
easily felt as the dominant one. The heartrate
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values of the two daily trials were averaged
out in order to provide a singular value
which represents the arousal level of the
participant at the daily anxiety level.
The final hypothesis was tested through
the use of a self-made questionnaire
(Appendix B) that was created with the
purpose to evaluate the severity of difficulty
for making a certain decision. Each time a
decision was made that was of significance
(e.g., which route to drive to school), the
participant would write down what the
decision was, what time the decision was
made at, as well as rate the difficulty of the
decision on a 5-point scale, in which 5 being
“Very Difficult” and 1 being “Very Easy”.
Before the participant was to go to bed, the
difficulty levels were all added together, and
an average value was recorded based on the
number of decisions that day. The value that
represented the average difficulty level of
decisions that day was compared with the
daily fear/anxiety level from the Pollock
Modified-POMS scale.
2.3.2 Experimental Study
The participant was tested through
random assignment to either an experimental
or controlled condition in which they were
instructed to watch a film based on which
slip of paper they drew from the yellow
bucket. Based on either pulling a strip with
the name of a specific horror movie, or a slip
that simply read “Non-Horror”, the
participant was expected to watch the
assigned film, or a film of choice that was
not considered a horror film. Once the film
was finished for the non-horror film, the
participant completed three trials of the free
recall test using PEBL Testing and took the
average percentage of correctly recalled
words. If the participant was assigned to
watch a horror film then, at the point in the
film when the participant believed they were
at the height of their anxiety/fear, they

completed three trials of the free recall test
using PEBL Testing in which the average of
correctly recalled words was recorded. The
participant ensured that they were able to
watch a maximum of 6 horror movies in
order to ensure that no harm came to the
participant or others and the participant was
not forced to finish the film if they did not
wish to do so once the free recall tests had
been completed.
3. Results
3.1 Baseline Study
Levels of anxiety/fear were measured
through the use of the Pollock ModifiedPOMS scale and were compared alongside
four different dependent variables (see
Figures 1, 2, 3, and 4). Each of the four
dependent variables produced different
values based on their correlations with
anxiety/fear levels (see Table 1). When
measuring the hippocampal (r = - 0.21, p =
0.522), prefrontal (r = -0.05, p = 0.874), and
reward system activity (r = -0.14, p = 0.668)
a negative correlation was observed between
the variables meaning that as one variable
increased, the other variable decreased.
Pertaining to how amygdalae activity related
to the different daily anxiety/fear levels, a
positive correlation resulted (r = 0.36, p =
0.263) which showed the largest correlation
out of all four of the dependent variables on
their independent variable. Although the
correlation between amygdalae activity and
anxiety level was the largest, the effect of
fear on hippocampal activity provided a
negative correlation (r = - 0.21, p = 0.522)
with the largest of the three negative
correlations, and was therefore used to test
for the Experimental portion of the study in
order to investigate further whether
increasing anxiety/fear levels will decrease
the activity of the hippocampus.
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3.2 Experimental Study
The mean of correctly recalled words
under controlled conditions of watching a
“Non-Horror” film was 46.8 (SD = 7.62)
and the mean of correctly recalled words
under experimental conditions, watching a
“Horror” film was 36.5 (SD = 9.86) (see
Figures 5 and 6). These data results were
analyzed using a t-test and the results were
not statistically significant, t (10.0) = 2.03, p
= .07 (see Table 2).
4. Discussion
The present study was first carried out
under longitudinal baseline conditions in
order to determine how the effects of
anxiety/fear affect an individual with
Generalized Anxiety Disorder (GAD) who
was a Psychology student at Camosun
College. The hypotheses predicting that an
increase in anxiety/fear levels will cause a
decrease in activity within two different
brain regions, the hippocampus and the
prefrontal cortex, proved to be expressed
through the negative correlations shown in
the results. Another negative correlation to
note that approved the original hypothesis
above, but with a decrease in reward system
activity instead of a brain structure. There
was also a negative correlation between the
two variables which proved that as one
increased, the other would decrease. The
hypothesis that did not conclude to be
accurate was that as anxiety/fear levels
increased, there would be a decrease within
amygdalae activity. The hypothesis was
proven as untrue due to a positive
correlation being present following the
Baseline Study.
Results from the present study support
the findings from past studies in which
hippocampal and amygdalae activity had
decreased in individuals with GAD
compared to their healthy counterparts when

being asked to perform multiple
suppression-retrieval tasks (Diwadkar et al.,
2017). Past research has also found that
there has been hypo-engagement within
multiple regions of the brain within the
medial lobe, containing the hippocampus
and amygdala (Diwadkar et al., 2017) which
showed a negative correlation for fears
impact on hippocampal activity, yet a
positive correlation between fear levels and
amygdalae activity. The present findings
also supported the results of a study that
compared healthy controls with individuals
who were diagnosed with GAD to see how
well they performed while making decisions
based on the context of a reward or
punishment being present at their moment of
choosing (White et al., 2017).
A major limitation in the study was that
there was only one participant. This one
participant only represented the age of 21,
female, with GAD and taking a SSRI
medication. The study may have been better
executed if there was a diversity of
participants who participated within the
study, including but not limited to: gender,
age, culture, and level of anxiety they
experience. Over the span of the 12 days in
which the Baseline Studies occurred, a wide
range of anxiety levels had been present
based on the Pollock Modified-POMS scale.
The fluctuating anxiety/fear levels could
have affected the results by affecting the
significance that the anxiety/fear levels have
in conjunction with each of the dependent
variables which would have affected the
correlation values within the Baseline Study
period by giving an unreliable correlation
value to test in the Experimental portion of
the study. Based on participant comments,
they had been anticipating having to watch
horror movies at some point during the 12day span of the experimental procedure,
which may have affected the results on the
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days under controlled conditions, possibly
producing a higher anxiety level.
Since the results of the Experimental
portion of the experiment were not
statistically significant, this implies that
while non-significantly associated in
baseline conditions, the level of fear
experimentally induced within the study did
not produce an effect upon free recall that
was great enough to be reliably detected.
Since the current study was unable to
determine whether anxiety/fear does cause a
decrease in hippocampal activity, future
studies should focus on studying which
structures undergo hypo engagement when
anxiety increases, in order to reduce the
negative effects that anxiety can have on
individuals in their daily lives. Future
studies need to prioritize this to ensure that
individuals with GAD are able to reduce
daily distress by providing them with some
effective strategies for reducing the feeling
that they are living their life within the
boundaries of their anxiety disorder.

during passive avoidance. The American
Journal of Psychiatry, 174(2), 110-117.
https://doi.org/10.1176/appi.ajp.2016.151114
10

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Appendix A

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