Many believe that understanding the human brain is one of the greatest challenges facing 21st century science. The difficulty here is immediately clear from the vast numbers of nerve cells or neurons (about 86 billion) in a human brain. Less obvious is the minute scale of nervous systems construction with many neurons only 0.01 mm in diameter. Problems of size and complexity have led to the study of simpler animals like snails, squid and flies that have complex behaviour but many fewer, often larger, neurons. In my research I wish to understand how nervous systems allow animals to behave. I use the fruit fly Drosophila and its circadian clock to address this question, as it manages to tell the time with just 75 pairs of neurons, and we have powerful genetic tools that let us read and write activity to specific neurons. Indeed, Drosophila has a long history of providing breakthroughs of how biology works all the way to humans, with six Nobel Prizes so far been awarded to research conducted with this model organism.

What is more, we can compare the findings in flies to other animal models, like mice, and even to humans. This is possible, since in order to adapt to varying internal and external conditions, all living life forms including insects and humans have evolved circadian clock mechanisms. Generally, clocks weaken with age, are affected by neurological disorders and clock disruption negatively affects health and well-being and can shorten lifespan. Furthermore, in our '24/7 society' an increasing proportion of the population experiences a desynchronisation of their circadian clock with that of the external world, due to shift-work, artificial lighting, noise pollution, anti-sleep drugs like caffeine, irregular sleep and eating patterns. This so-called 'social jet-lag' has lead to an alarming increase in health risks, and has been associated with cancer, obesity, depression, addiction and several sleep diseases resulting in about a third of people experiencing insomnia.