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Visualization of Brain Connectivity during Emotion induction

Guhan Seshadri N P1*, Muthumeenakshi S1, Geethanjali B1 and Pravin Kumar S1
  • 1 SSN College of Engineering, Department of Bio-medical Engineering, India

Introduction Emotions are multifaceted circumstances of reaction that persuades our routine and varies among individuals. Human emotions can be generally discerned from the elicited electrophysiological effects. Assessing the complex nature of emotion creation has recently achieved spotlight status in the field of neurosciences. Analysis of parts of emotions such as subjective feelings, physiological responses and expressive behavior, pave way for better comprehension. The present study evaluated the effect of perceived and induced emotion emphasizing on the negative valence and high arousal emotion. Additionally the study also visualized the activation of different regions of brain and their connectivity when processing emotionally aroused pictures. Material and Methods Twenty healthy adult participants had no preceding information about the experiment were chosen for this study on their individual interest. The average age was 22 ± 0.85 and they were right handed in order to avoid the lobe lateralization. All volunteers read and signed an informed consent before participating. The normative visual emotional stimulus was selected from International Affective Picture System after obtaining appropriate consent from the IAPS database. Perceived emotion was quantified using the subjective ratings from the Self-Assessment Manikin Scale (SAM scale) and the brain activity was recorded using the EEG from every subject. The recorded EEG signals for different conditions were pre-processed using wavelet de-noising technique and offline analysis was performed using wavelet packet decomposition to extract the relative component energies of various EEG bands. Friedman test was performed to evaluate the overall significance among the measured parameters (relative alpha, beta, and theta component energies) as they were not normally distributed. The Wilcoxon signed rank test was performed to measure the significant difference across the related groups and the significant value was set at p=0.05. Spearman rank-order correlation was carried out to understand the associations between the electrodes. Results and Discussion When the brain activation and functional connectivity representing the alpha EEG band was studied, the node strength at Fp1 was high for positive valence high arousal picture (Figure 1) when compared with negative valence high arousal pictures (Figure 2). The node strength at frontal electrode locations was same for both positive and negative valence pictures. The left frontal regions showed high functional connectivity with temporal and parietal lobe electrode locations, noted only for negative valence high arousal pictures. Apart from that a strong association was noted at occipital, parietal electrodes only while viewing negative valence high arousal pictures. In case of theta component energy, the node strength was high for right hemisphere electrode locations for negative valence high arousal pictures (Figure 3), this was not noted for positive valence (Figure 4). Strong functional connectivity and node strength were noted at temporal and parietal electrode locations for only negative valence high arousal pictures. The occipital lobe electrodes were equally engaged for both the valence categories. Due to the display of positive valence high arousal pictures, the left frontal electrode (f3) was engaged with temporal and parietal electrode locations. In theta band, the frontoplanar electrodes were not functionally related to negative valence whereas a strong inter-connectivity was established between them during positive valence high arousal pictures. The brain activation diagrams focusing on the Beta EEG band was scrutinized. During negative valence high arousal strong functional intra-connectivity was noted in beta component energy (Figure 5) at parietal, temporal and frontal lobe electrode locations. In the case of positive high arousal (Figure 6), the node strength at left frontal locations were high but they were not functionally connected, even though the node strength at the right frontal electrode location ( f4) was the lowest, it was observed to be highly associated with temporal and parietal electrode locations. The occipital lobe electrodes were equally engaged for both the valences apart from that, the frontoplanar electrodes were not functionally related in support of beta component energy for both valences. Conclusion The present study concludes that the visualization of neuronal activity inclusive of intra and inter functional connectivity across various electrodes locations along with lobe lateralization provides better understanding of assorted emotional conditions. Based on the obtained results, a strong functional connectivity was noted at right frontal (F4) with temporal and parietal lobe electrode locations for alpha, beta and theta component energies while viewing negative valence high arousal pictures when compared to positive valence high arousal pictures. Similarly on observation, the occipital lobe electrodes (O1 and O2) were found to be equally engaged and highly correlated for both negative and positive valence categories. Particularly, when theta band was studied, there were considerable differences between the two valence categories, the frontoplanar electrodes (Fp1 and Fp2) were not functionally related in favor of negative valence whereas a strong inter-connectivity was seen to be established between them during positive valence high arousal pictures.

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Keywords: Emotions, EEG, functional connectivity, IAPS, Wavelet packet

Conference: Neuroinformatics 2016, Reading, United Kingdom, 3 Sep - 4 Sep, 2016.

Presentation Type: Poster

Topic: Visualization

Citation: Seshadri N P G, S M, B G and Kumar S P (2016). Visualization of Brain Connectivity during Emotion induction. Front. Neuroinform. Conference Abstract: Neuroinformatics 2016. doi: 10.3389/conf.fninf.2016.20.00090

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Received: 24 Jul 2016; Published Online: 01 Sep 2016.

* Correspondence: Mr. Guhan Seshadri N P, SSN College of Engineering, Department of Bio-medical Engineering, Chennai, TamilNadu, 603110, India, guhan131192@gmail.com