Developing 2-photon imaging with in vivo optogenetic stimulation of the larval brain of Drosophila melanogaster.
Start: June 1st 2024
Abstract
As a Postdoc in Dr. Claire Eschbach's team in NeuroPSI Paris-Saclay, I am now studying the formation of flexible memory as a key ability to track the value of a choice outcome for adaptive decisions in dynamic environments. I am looking at how brain circuits compute such values in the larval brain of Drosophila melanogaster. Drosophila larvae uniquely allow a combination of sophisticated, multi-scale, approaches. With online tracking, specific genetic targeting of neurons (to e.g. activate, silence, or image neuronal activity), computational modelling of networks, and the use of a detailed connectome as a road map, we can study the way recurrent networks implement reinforcement learning to an unprecedented level of precision. Using these advanced neurogenetics approaches I am recording specific dopamine neuron activity, both Calcium and dopamine release (a red fluorescent GPCR-activation–based dopamine sensors, GRABDA), using 2-photon microscopy either with the larva brain in-vivo (agar technique) or ex-vivo. First, I am looking at surprisingly inerrant activity fluctuations depending on the dopamine neuron. Associated with optogenetics and pharmacological stimulation I want to identify the identity of each neuron and how those inerrant fluctuations impact behaviour. Secondly, I am quantifying the dopamine realise when a neuron receives different levels of optogenetic activation. This will help us better understand larva behaviour when experiencing optogenetic activation and will be a base for further studies. On the other hand, I am helping in the making of a decision-making Y maze, with odour release, to quantify decisions while optogenetically activating specific neurons.
