GRIFFITH LAB @ BRANDEIS
Sleep is a highly conserved, homeostatically-regulated feature of complex organisms. It is, however, a costly behavior since sleeping animals lose opportunities to feed and mate and are vulnerable to predation. The brain must therefore integrate salient features of the animal's internal state and its current environment to determine whether to sleep.
We use genetics and pharmacology to manipulate behavior in intact animals with the goal of understanding the molecular, cellular and circuit level regulation of sleep
Identifying and understanding sleep states in Drosophila
Sleep pressure and sleep depth are key regulators of wake and sleep. We have developed analysis tools for high-resolution, noninvasive measurement of sleep pressure and depth from movement data. We also develop a Hidden Markov Model that allows visualization of distinct sleep/wake substates. These hidden states have a predictable relationship with sleep pressure and depth, suggesting that the methods capture the same underlying processes.
microRNA regulation of sleep
To probe the role of microRNAs in Drosophila sleep, we utilized a library of "miR sponges" generated by the Van Vactor lab to disrupt the function of 145 different microRNAs. We identified a number of microRNAs that had significant effects on sleep, including bantam, let-7 and mir-190. Current work revolves around understanding the molecular and cellular processes regulated by these microRNAs and how they regulate sleep.
Sleep roles of ellipsoid body ring neuron subtypes
Ellipsoid Body (EB) ring neurons have been associated with many features of sleep including homeostasis and sleep structure. To understand the roles of different anatomical subtypes, we conducted a thermogenetic screen of GAL4 lines expressing in different sets of ring neurons to identify functional correlates of EB subcircuits.