Continuous wavelet application for the assessment of neural potential interaction during time discrimination task.

Abstract

The aim of the paper is to assess the interaction of the neural potentials during a time discrimination psychoacoustic task. Ten subjects participated in the experiment and were asked about the equality of two acoustic pulses: one reference of 500ms and one trial that varied from 420ms to 620ms. During the experimental procedure, Electroencephalogram (EEG) and Event Related Potential (ERP) signals were recorded. The analysis combines results from Continuous Wavelet signal processing and subjects responses which were analyzed based on psychoacoustic theory. The Wavelet Coherence metric index is employed to assess the interaction of neural potentials. The results indicate the points at which the duration of the trial pulse is equal to 560ms and 460ms as the minimum and maximum of the Wavelet Coherence metric index, respectively. This observation is valid in most electrodes, for all basic EEG rhythms, revealing in parallel the differentiation of the gamma rhythm, in relation to the others. These maximum and minimum values are correlated to the Just Noticeable Difference (JND) in pulses duration, calculated by the psychoacoustic analysis.