Recording neural circuits: in vivo calcium imaging

Abstract

Microendoscopic calcium imaging is a technique that allows the monitoring of neural activity in freely moving animals, making it possible to establish a direct relationship between the activity of a specific region of the brain and animal behaviour. This technique is based on recording the intracellular concentration of Ca2+ fluctuation in neurons expressing genetically encoded indicators for this ion (e.g. GCaMP). The fluorescence emitted by these indicators is captured by a miniaturised fluorescence microscope (miniscope) that is attached to the animal skull. This enables us to register the cell population expressing the specific indicator with spatial and temporal resolution. This method would be very useful for the study of circuits associated with social defence, like the septo-hippocampal-hypothalamic circuit, as they would allow us to evaluate the dynamics of the neuronal activation of this circuit during social stress. During the internship period at the Max Planck Institute for Biological Intelligence, we will contribute to ongoing projects involving the technique of in vivo calcium imaging. More specifically, we will collaborate on experiments to evaluate the activity of central amygdala neurons involved in feeding. This experience will be important so that, in the future, we can implement this technique in Brazil. (AU)