1. Firstly, evaluate the optimization effect of a specific virus GCaMP indicator (this process may require multiple dilutions) through histological examination (note: transgenic models do not require it).

2. Inject the virus into the brain area of interest and express GCaMP on specific cells.

3. Embed the integrated lens into the cell region expressing GCaMP6.

4. Imaging hundreds of neurons and recording data for several months. When neuronal cells are activated, intracellular calcium (Ca2+) levels increase, and GCaMP merges with calcium to generate transient fluorescence signals (modified from Gulati et al., 2017 JoVE: 124, e55579).

5. Transfer the calcium ion signal to the computer through a data acquisition host (DAQ).