SLEEP ACROSS TAXA - Invited Review
Comparative biology of sleep in diverse animals Lakhiani R, Shanavas S, and Melnattur K. Journal of Experimental Biology. 226 (14): jeb245677 Sleep is a familiar, periodic occurrence in our lives. Despite its place in everyday experience, the existence of this suspended state of consciousness has intrigued and puzzled philosophers and scientists for decades. For much of its history, sleep science has focused on humans and mammals. In contrast, in the last 20 years or so, it has become increasingly clear that sleep is essentially universal. Sleep states have been observed in animals from mammals to cnidaria. Here, we review recent progress in sleep science through the lens of comparative physiology. We highlight broad insights into sleep phenomenology, physiology and function that have come from this comparative approach. |
SLEEP AND AGEING - Invited Book Chapter
Sleep, Ageing and Cognitive Decline Melnattur K, 2023. In Jagota A (eds). Sleep and Clocks in Aging and Longevity. Cham: Springer International Publishing Sleep changes with age – older adults sleep poorly compared to younger adults. What specific characteristics of sleep are altered with age? What are the age-dependent neurobiological changes that might explain these sleep deficits? Does poorer sleep lead to deleterious outcomes for the elderly? Can enhancing sleep reverse cognitive decline? This chapter addresses these questions. First, we describe prototypical changes in sleep architecture and physiology with healthy ageing, and discuss their potential underlying neurobiological basis. Second, we consider two potential outcomes of sleep – clearance of toxic metabolites, and learning and memory. We describe age dependent changes in these phenomena, and consider possible neurobiological explanations for these observations. While we mostly focus on human and mammalian work in this chapter, we recognise that sleep is a near universal phenomenon in animals, and therefore do discuss parallels with invertebrates, particularly the fly Drosophila wherever appropriate. |
SLEEP-PLASTICITY
Disrupting flight increases sleep and identifies a novel sleep promoting pathway. Melnattur, K, Zhang, B, and Shaw PJ. Science Advances, May 2020. Here I show that impairing flight in the fly Drosophila increases sleep. Further I define a novel tri-synaptic sleep-regulatory circuit from pheromone sensing neurons on the fly’s wing to the brain that mediates this effect |
SLEEP-DEPENDENT PLASTICITY
A conserved role for sleep in regulating spatial learning. Melnattur, K; Kirszenblat, L; Morgan, E; Militchin, V; Sakran, B; English, D; Patel, R; Chan, D; vanSwinderen, B, and Shaw PJ Sleep, March 2021. We adapted a spatial learning assay to study the relationship between sleep and plasticity. Amongst other findings, we find that flies exhibit dramatic age-dependent declines in spatial learning that are reversed by enhancing sleep. These results suggest that sleep can function effectively as a therapeutic. Crucially, spatial learning in animals has many parallels with human declarative memories, suggesting that our results will be broadly applicable. |
PRIMER
Staying awake to stay alive: A circuit controlling starvation-induced waking. Melnattur, K; and Shaw PJ PLoS Biol 2019 A comment on Yurgel et al. |
NEURAL SUBSTRATES OF COLOR VISION
Multiple redundant medulla projection neurons mediate color vision in Drosophila. Melnattur, K; Pursley, R; Lin, T-Y; Ting, C-Y; Smith, PD; Pohida T, and Lee C-H J Neurogenetics 2014 We developed a novel flight simulator based assay to demonstrate the flies possess a colour vision system. Using this assay we show that colour information is represented along 3 redundant axes at the level of the first synapse from the photoreceptors. |
OLFACTORY CIRCUIT ASSEMBLY
The Sox Gene Dichaete is expressed in local interneurons and functions in development of the Drosophila adult olfactory circuit. Melnattur KV; Berdnik B; Rusan Z; Ferreira CJ, and Nambu JR Dev Neurobiol 2013. We find that the SOX gene Dichaete, the fly homolog of mammalian SOX2, is expressed selectively in olfactory local interneurons of the antennal lobe (the fly equivalent of the mammalian olfactory bulb). Interestingly, mutations in Dichaete exhibited mistargeting of sensory neuron afferents and projection neuron dendrites. This suggests a surprising non-cell autonomous role for local neurons in olfactory circuit assembly. |
Cover Image: Detail from "Noon: Rest from work after Jean-Francois Millet 1890", Vincent Van Gogh. Image in the public domain