Brain-Computer Music Interfaces (BCMIs) aim to allow users to control music using their brain activity information. In this thesis the design and implementation of a BCMI for controlling the expressive content of musical pieces using emotions is presented. Human emotions can be characterized as a combination of arousal and valence values. However, the variability of these values across different subjects complicates the use of emotions for controlling music expression. Two experiments are presented to study the best approach for calculating arousal and valence value boundaries. The obtained...