We are learning how to analyze EEG signals for a project we are working on regarding traumatic brain injury in rats. It seems that one of the best methods for analyzing phase in a signal is to look at the Hilbert Transform. I invested a good deal of time yesterday learning about this process and I was pretty impressed. The two videos below are lectures from the Indian Institute of Technology about the underlying math. I summarized the videos in a short set of notes which is linked here. I'll update again later once we have a better idea on how to apply this technique to EEG analysis.