Auditory training alters the physiological detection of stimulus-specific cues in humans.
OBJECTIVE
Auditory training alters neural activity in humans but it is unknown if these alterations are specific to the trained cue. The objective of this study was to determine if enhanced cortical activity was specific to the trained voice-onset-time (VOT) stimuli 'mba' and 'ba', or whether it generalized to the control stimulus 'a' that did not contain the trained cue.


METHODS
Thirteen adults were trained to identify a 10ms VOT cue that differentiated the two experimental stimuli. We recorded event-related potentials (ERPs) evoked by three different speech sounds 'ba' 'mba' and 'a' before and after six days of VOT training.


RESULTS
The P2 wave increased in amplitude after training for both control and experimental stimuli, but the effects differed between stimulus conditions. Whereas the effects of training on P2 amplitude were greatest in the left hemisphere for the trained stimuli, enhanced P2 activity was seen in both hemispheres for the control stimulus. In addition, subjects with enhanced pre-training N1 amplitudes were more responsive to training and showed the most perceptual improvement.


CONCLUSIONS
Both stimulus-specific and general effects of training can be measured in humans. An individual's pre-training N1 response might predict their capacity for improvement.


CONCLUSIONS
N1 and P2 responses can be used to examine physiological correlates of human auditory perceptual learning.
Tremblay
Kelly L
KL
University of Washington, Department of Speech and Hearing Sciences, Seattle, WA 98115, USA. tremblay@u.washington.edu
Shahin
Antoine J
AJ
Picton
Terence
T
Ross
Bernhard
B
D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D001931:Brain Mapping; D003463:Cues; D004569:Electroencephalography / Q000379:methods; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D007839:Functional Laterality; D006801:Humans; D007858:Learning / Q000502:physiology*; D011571:Psychoacoustics; D011930:Reaction Time / Q000502:physiology*; D015203:Reproducibility of Results; D013057:Spectrum Analysis; D014793:Visual Cortex / Q000502:physiology; D055815:Young Adult