The temporal resolution of the human primary auditory cortex (AC) was studied using middle-latency evoked fields. Paired sounds with either the same or different spectral characteristics were presented with gaps between the sounds of 1, 4, 8 and 14 ms. Spatio-temporal modelling showed (1) that the response to the second sound was recognizable with gaps of 1 ms and rapidly increased in amplitude with increasing gap durations, (2) an enhanced N40m amplitude at gaps > 4 ms, (3) delayed N19m-P30m latencies when the stimuli were different. The median psychoacoustical thresholds were 1.6 ms for the same stimuli and 2.5 ms for different stimuli, confirming the electrophysiological evidence for rapid pattern-specific temporal processing in human primary auditory cortex.
1Section of Biomagnetism, Department of Neurology, University Hospital of Heidelberg, Germany
2Rotman Research Institute, Baycrest Centre for Geriatric Care, University of Toronto, Canada
3Department of Neuroradiology, University of Heidelberg, Germany
4Corresponding Author: André Rupp
Acknowledgement: This study was supported by the Deutsche Forschungsgemeinschaft (SCHE-558/2–1).
Received 22 August 2000; accepted 10 September 2000