Sleep is near universal in animals and recognized to be plastic and influenced by ecological factors and environmental changes. Changes in sleep in turn are thought to facilitate neural plasticity and consequently, changes in behaviour. The mechanisms that might regulate sleep-plasticity, and the mechanisms by which sleep might support adaptive behaviour are however, not well understood. Our recent work speaks to both of these aspects. First, we found that manipulations that impair flight in Drosophila increase sleep as a form of sleep-plasticity. Further, we identified a novel neural circuit that mediates this effect. This circuit consists of pheromone-sensitive sensory neurons, their partner projection neurons, and targets of the projection neurons in the brain.
Second, we have adapted a spatial learning assay to explore the relationship between sleep and plasticity. Excitingly we find that flies exhibit age dependent declines in spatial learning that are reversed by enhancing sleep. These data reveal an unexpected role for flight in regulating sleep, provide new insight into how sensory processing controls sleep need, and how sleep impacts adaptive behaviour.
Krishna is interested in understanding how brains generate adaptive behaviours. To get at these questions, his lab uses a variety of techniques including genetics, circuit tracing tools, physiology and behavioural measurements. His current interests are in studying sleep in the fly Drosophila. His work speaks to two aspects of sleep – that sleep is plastic i.e. modifiable by environmental changes, and in turn supports brain plasticity and learning. In so doing, his work addresses fundamental questions around both the how and why of sleep.
Prior to joining Ashoka, Krishna was a Staff Scientist in the Dept of Neuroscience, Washington University School of Medicine studying sleep in the fly Drosophila with Dr. Paul Shaw. He received a PhD from the University of Massachusetts, Amherst studying neural development with Dr. John Nambu. From development, he went on to first investigate the neural substrates for colour vision at the National Institutes of Health, Bethesda, before finding his true intellectual home in the study of sleep in flies.