I want to pursue my phd in brain signal processing. More specifically, I want to apply the machine learning algorithm in the signal processing of the brain signal.
I don't know all the centers, but one good one where I did my bachelor's in AI is in Nijmegen, connected to the Radboud University: Donders Institute for Brain, Cognition and Behaviour. They do world leading research in BCI (Brain Computer Interfacing) and signal processing. Also the Max Planck Institute for Psycholinguistics is located there!
Be sure to check out if they have open Phd applications, or maybe even vacancies for what you're looking for. Nijmegen is a great cosy Dutch city and the Radboud university has amazing work on neuroscience, signal processing, BCI and AI.