The Role of the Appendix in Cognitive Tasks: A Case Study

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	Although previously, the appendix was thought to play a minor role
in cognitive tasks, we have found that its role can not be underestimated.
Using neuropsychological techniques, we have identified no less than five
distinct domains which the appendix mediates.
	SM, a recent A-appendectic, was observed in the hours preceding
and days following the surgical procedure in which his appendix was
removed.  We made the following observations and conclusions:

	In the period immediately previous and following the operation,
the patient experienced acute pain in the abdominal region.  The patient
also experienced loss of appetite and moderate nausia.  We surmise that
because during this time, the appendix was not functioning properly (or
was not functioning at all since it had been excised), the organ plays
three roles: the appendix primarily suppresses abdominal pain, but also
mediates the experience of nausia and appetite.  Some may argue that
nausia and appetite are actually two sides of the same neuropsychological
coin, but we point out that a clear double dissociation occurs in the case
of "Tyler's Tummy-Ache" (1994), where young Tyler told his mommy that he
was hungry but his stomach still hurt.
	In the days following the surgical procedure, SM experienced
extreme drowsiness and irregular sleeping hours.  We conclude that the
appendix also plays an important role in sleep regulation, and suggest
circadian rhythms may also be mediated by this unlikely attachment to the
the intestine.

	Finally, we observed that the patient quickly recovered from the
afflictions linked to the appendix failure.  We thus surmise that although
the appendix plays an important role in cognitive function, the brain is
highly malleable and can quickly assume the roles formerly played by the
appendix.  This strikes us as a strong evolutionary advantage; any system
that regulates such primal and important sensations as hunger, pain, and
sleep is likely to have backup systems that lie dormant until the primary
systems fail.

	Previously, the appendix was considered a vestigial part of the
digestive system rather than an integral part of the nervous system.  We
have hopefully shown that this classification is misguided and that
humans, just like the dinosaurs, have one brain in our heads, and one in
our abdomens.  We expect that further research using animal studies and
neuroimaging is likely to uncover other roles that the appendix plays, and
hope this case study has opened up a new line of research.

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