FREE ESSAY ON AMYGDALA ACTIVITY

AMYGDALA ACTIVITY

Review of Amygdala activity at correlated with long-term, free recall of emotional
information
This article reviewed an experiment that tested the role of the amygdala in emotional
memory. To be specific it hypothesized that if the amygdaloid complex (AC) was primarily
involved with the formation of long-term memory during emotionally arousing situations,
then the PET analysis would reveal AC activity related to retention of the relative
emotional, but not relatively neutral, films. 
The experiment used eight right-handed male subjects between 20 and 24 years old. While
at first it was not clearly stated why the subjects used were all the same, but women,
left-handed people, and subjects of differing ages were purposely omitted in favor of
right-handed males of a specific age for use as a control. These subjects were shown two
videos, one with emotionally neutral film clips (N) and one with emotionally arousing
film clips (E). Each video contained 12 clips. The subjects were asked to rank each film
on the basis of emotionality from 0 (being the lowest) to 10 (being the highest.) The
videos were also ranked on how well the subject understood each film on a scale from 0 to
10. The E and N films did not differ in their level of understandability. The films were
ordered in such a way that it would maximize the chances of detecting glucose differences
between E and N sessions. Since positron emission tomography was used, this was a good
idea because most of the measured activity would relfect the first 15-20 minutes of
tracer reuptake. Three weeks after the experiment, the subjects were asked to recall as
many film clips as possible from both film sessions.
As expected the E films were ranked significantly higher than the N films. The subjects
could also recall more E films than N films when asked three weeks after the experiment.
The scientific paper presents simple, but effect, graphs showing the discrepancies
between the ratings of E and N films as well as the number of N and E films recalled. The
major finding of the study pointed to the right AC in which activity during E films could
be linked to memory of the E films. 
Although Figure 2 was somewhat confusing to the readers, Figure 3 clearly shows a
scatterplot relationship that existed between number of films recalled and right amygdala
glucose levels in E films with no apparent relationship existing between those two in N
films. The experimenters then offer possible explanations as to why the asymmetries
between the right and left amygdalas may have occurred, but each of the explanations
supported the authors' hypothesis. Because of this fact, the explanations may have been
somewhat biased or some explanations may have been purposefully ommitted. Although this
may have been biased, the experimenters did not fail to mention that other parts of the
brain were associated with memories of emotional nature, without having any apparent role
in the formation and retention of neutral memories.
Overall, the results supported the hypothesis that the amygdala plays a significant role
in the free recall of emotional activities, but not neutral activities. The experimenters
clearly presented the information in the scientific paper with only a few confusing
spots. As stated earlier, they failed to state why eight male right-handed subjects were
used. The experimenters also didn't test positive emotional clips; they only tested
negative emotional clips. This may have changed the findings if this had been done.
Another weakness of the experiment was not stating how the subtraction method worked,
making it hard to follow some parts of the paper.