Abstract
Drosophila phototransduction is a well-established model for characterizing biological processes, such as calcium signaling. Here, we present a protocol for electroretinogram (ERG) recording, an in-vivo physiological assay extensively used in Drosophila phototransduction research to measure light-evoked field potential responses of photoreceptors and neurons in the lamina neuropil. We describe fly preparation and electrode placement, followed by pretest setup, ERG recording, and data analysis. This protocol enables assessment of photoreceptor performance and visual synaptic transmission between photoreceptors and downstream lamina neurons. For complete details on the use and execution of this protocol, please refer to Han et al. (2006), Hu et al. (2012), and Wu et al. (2021).