Grand average of the MMN and P3a at the frontal pool of electrodes separately for CH synesthetes (upper part) and non-synesthetes (lower part). The MMN and P3a are shown for the four deviants (black: 438, blue: 422, green: 416, and red: 264 Hz tones). The red rectangle in solid line indicates the time frame for the MMN while the red rectangle with the dotted line indicates the time frame for the P3a.
Jäncke et al. BMC Neuroscience 2012 13:151 doi:10.1186/1471-2202-13-151