O032 It's OK to Lose your Head!

INTRODUCTION: Sleep is something that we all do, regardless of how much or how little. But why we sleep, and how sleep evolved is still something of a mystery. This research looks at a novel attribute of flatworms – the ability to regenerate whole body structure, and how neural regeneration may impact sleep. METHODS: Using behavioural methods, I observed the behaviour of flatworms under a 12:12 LD lighting condition. Once the baseline was established, I used a small razor to cut the head off each individual. Recordings took place every two weeks, for baseline, post-decapitation, and then at full regeneration. RESULTS: Animals that were re-growing their brains moved a lot less than their original intact data showed, a small circadian rhythm was still present. Once the animal had regained its eyespots, and thus regenerated, this rhythm was more prominent and on its way to returning to intact levels. Animals that were re-growing their bodies also showed a persistent circadian rhythm in their activity throughout the regeneration process. DISCUSSION: This research is very exciting for several reasons. It shows that flatworms themselves rely on more than just their brain and eyespots to sense the light and environment around them. It also suggests that circadian rhythms are deeply engrained and that behaviours that arise from this, such as locomotion can still be influenced even without the presence of a brain – the neurons in the ventral nerve cords, and other body systems may be equally as important.