Effects of brief discrimination-training on the auditory N1 wave

We determined whether the human N1 evoked by tones with different frequencies might be affected by a brief discrimination-training at one specific frequency. During 1 h training, subjects learned to discriminate a 1062 Hz tone from another tone. Before and after training, subjects heard for 26 min tones with a frequency of 1000 Hz, replaced every sixth one by test tones with frequencies randomly and equiprobably chosen as 835, 886, 941, 1000, 1062, 1128 or 1198 Hz. The N1 to the test tone was larger when its frequency was further from the repeating frequency. After training N1 s were attenuated to all tones except the trained and repeated ones, indicating a refractory frequency effect, long-term habituation, and sensitization to the repeated and trained tones.