Abstract
In order for an organism to adapt to daily changes in the environment, it must have the capacity to regulate gene expression, morphology of neurons, and physiology. The adaptability of the nervous system to change in accordance with the surroundings, called “neuronal plasticity”, is remarkable and has been observed in a number of different vertebrates and invertebrates such as Drosophila melanogaster. The term “circadian rhythm” was coined to describe cyclical daily changes, under the influences of the core molecular clock and external cues such as light. Neuronal plasticity exhibits circadian controlled changes, which include changes in axonal diameter, branching complexity, synapse number, as well as vesicle number. Our results below address the time dependent changes in the spatial distribution of synaptic proteins, Bruchpilot and Discs large homolog 1, as well as what internal and external components contribute to these rhythms in order to gain an insight into synaptic plasticity. In summary, we have shown that there are specific time-of-day spatial distributions of synaptic proteins that are dependent on external and internal cues including light, activity, and the biological clock.