Figure 2.

Mismatch Negativities (MMNs—i.e., Event-Related Potentials (ERPs) to the deviant stimuli minus ERPs to standard stimuli) averaged across large and small deviant stimuli and before and after training at Fz (with mastoid reference, top) and at mastoid electrode (mean of left and right mastoid electrodes, with nose reference, bottom) for Voice Onset Time (VOT, left), Duration (middle), and Frequency (right) deviant stimuli. Note the clear polarity inversion between Fz and mastoid for VOT and duration changes but not for frequency changes.