Temperature representation in the Drosophila brain.

• Autores: Dominic D. Frank, Genevieve C. Jouandet, Patrick J. Kearney, Lindsey J. Macpherson, Marco Gallio
• Localización: Nature: International weekly journal of science, ISSN 0028-0836, Vol. 519, Nº 7543, 2015, págs. 358-361
• Idioma: inglés
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• Resumen

  • In Drosophila, rapid temperature changes are detected at the periphery by dedicated receptors forming a simple sensory map for hot and cold in the brain 1. However, flies show a host of complex innate and learned responses to temperature, indicating that they are able to extract a range of information from this simple input. Here we define the anatomical and physiological repertoire for temperature representation in the Drosophila brain. First, we use a photolabelling strategy 2 to trace the connections that relay peripheral thermosensory information to higher brain centres, and show that they largely converge onto three target regions: the mushroom body, the lateral horn (both of which are well known centres for sensory processing) and the posterior lateral protocerebrum, a region we now define as a major site of thermosensory representation. Next, using in vivo calcium imaging 3, we describe the thermosensory projection neurons selectively activated by hot or cold stimuli. Fast-adapting neurons display transient ON and OFF responses and track rapid temperature shifts remarkably well, while slow-adapting cell responses better reflect the magnitude of simple thermal changes. Unexpectedly, we also find a population of broadly tuned cells that respond to both heating and cooling, and show that they are required for normal behavioural avoidance of both hot and cold in a simple two-choice temperature preference assay. Taken together, our results uncover a coordinated ensemble of neural responses to temperature in the Drosophila brain, demonstrate that a broadly tuned thermal line contributes to rapid avoidance behaviour, and illustrate how stimulus quality, temporal structure, and intensity can be extracted from a simple glomerular map at a single synaptic station.