We present an approach to elucidate brain ERP and slow rhythm responses in creative insight analysis experimental setup. Eight professional dancers take part in EEG recording experiments in which they are requested to mark inspiring pictures presented in random series. Three sets of images presenting dance, emotional and geometrical reference scenes are displayed in random sequences. Brainwave responses are captured with eight dry EEG electrodes g.SAHARA connected to g.MOBIlab+ portable amplifier by g.tec, Austria, with 256 Hz sampling frequency.
[Method] In order to clean and remove EEG interferences from recordings of free behaving subjects and to improve ERP response analysis a synchro-squeezing transform (SST) is applied. SST outperforms the classical time-frequency analysis methods of the non-linear and non-stationary signals such as brainwaves. The proposed method is also computationally more effective comparing to the already classical empirical mode decomposition technique, which successfully deals with muscular artifacts in EEG. The SST filtering allows for efficient and fast EEG preprocessing application which is essential in the case of large and noisy datasets processing. The visually evoked ERP responses after SST-based preprocessing are averaged within the two inspiring and non-inspiring sets.
[Results] We observe the large positive ERP deflections around 1000 ms latency for dance and emotional scenes presenting images. Responses to the geometrical reference images result in lower differences at the same latency. The differences are observed in frontal EEG electrodes FCz and AFz covering the frontal brain lobe. The time frequency contrast analysis of the Morlet-wavelet-transformed ERP responses results in significant changes in alpha and theta EEG frequency ranges of inspiring versus non-inspiring self-reported dance and emotional scenes images with larger differences of the above EEG waves in frontal, temporal, parietal and occipital lobes as observed in FCz, C3, C4, Pz and Oz electrodes. The differences are not observed for the reference geometrical images set. The results presented offer a step forward in creative process functional analysis.