Neural Correlations of Improving in Auditory Temporal Discrimination based on Entropy of EEG Signals

Abstract

Temporal processing in human is universally employed in wide-ranging sensory motor tasks. The sensory and motor actions by the nature require a precise perception and management of time intervals. However, underlying brain mechanism of perception and learning of time intervals is not vividly clear. In this study by employing an auditory time discrimination task, we investigated how the perceptual learning of time intervals occurs within a distributed system in the brain. We assessed ability of time interval discrimination in a six-day learning process. Therefore, sixteen healthy young adults were recruited to participate in the learning process with the application of a force selection paradigm. The nominated subjects underwent six days training for time differentiation in intervals of 300ms and 1000ms with frequency of 1 KHz and 4 KHz, respectively. Beside the behavioral data, the subjects' brain activities were also measured using a 16 channel EEG recorder. The behavioral results showed significant improvement of the discrimination accuracy in both intervals. Further, the improvement of time interval discrimination was significantly correlated with variations of EEG entropy particularly at the frontocentral and temporoparietal regions in theta and beta frequency bands. The findings clearly emphasize on the crucial role of changes in entropy of brain activities distributed over the brain for perception and learning of time intervals. We hope results of the present empirical research could shed a light on general understanding of the underlying brain mechanism of time interval discrimination.