The Role of the Appendix in Cognitive Tasks: A Case Study
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: ROLE OF APPENDIX 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. PLASTICITY OF THE BRAIN 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. CONCLUSION 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.