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Time-dependent cortical asymmetries induced by emotional arousal

Time-dependent cortical asymmetries induced by emotional arousal. EEG analysis of event - related synchronization and desynchronization in Individually defined frequency bands. Ljubomir I. Aftanas, Anton A. Varlamov, Sergey V. Pavlov, Viktor P. Makhnev, Natalya V. Reva 2001.

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Time-dependent cortical asymmetries induced by emotional arousal

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  1. Time-dependent cortical asymmetries induced by emotionalarousal EEG analysis of event-related synchronization and desynchronization in Individually defined frequency bands • Ljubomir I. Aftanas, Anton A. Varlamov, Sergey V. Pavlov, • Viktor P. Makhnev, Natalya V. Reva 2001 Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  2. Questions raised by the article: • Do interhemispheric asymmetries, emerging during affective processing and indexed by ERD/ERS measures, vary with the judged arousal of an affective picture foreground? • If so, when, where and at which frequencies does this occur? Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  3. The experiment • International Affective Picture System (IAPS) stimuli with low, moderate and high arousal (LA, MA and HA) content, • 62-channel EEG, • Skin Conductance Response (SCR), • Heart Rate (HR). Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  4. The experiment • Participants are instructed to attend to the pictures, No overt response is required, to keep inherent affective reactions to these stimuli. • Event-related desynchronization (ERD) and synchronization (ERS) • theta and alpha frequency band was measured Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  5. Sequence of one experimental trial • Blank screen then small cross for 4s • Presentation of a picture for 6s • Total length of EEG epoch recorded : 12s (5s before and 7s after picture onset) • The IAPS stimuli are subjectively rated using the Self-Assessment Manikin Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  6. Arousal / Valence Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  7. IAPS Stimuli Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  8. Self-Assessment Manikin (SAM) Pleasure Arousal Dominance Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  9. Results Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  10. Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  11. Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  12. Results Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  13. Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  14. Results • Theta, alpha-1 and alpha-3 bands : effects of arousal discrimination. • Theta and alpha-3 bands : association with hemispheric asymmetries in the anterior /posterior direction of the cortical plane. • Discriminative properties of thetasynchronization in the time period of 100-700ms post-stimulus. • In the alpha-1 and alpha-3 bands, discriminative process : 800-1200ms. Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  15. Conclusions • The skin conductance and heart rate data provided important support that picture differences are attributable to emotional arousal. • Affective processing seems to be frequency-dependent, the theta oscillating networks were the fastest in affect discrimination. • Time-dependence of hemisphericasymmetries induced by affective processing. Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  16. Conclusions • Posterior regions of the right hemisphere involved in the modulation of emotion-related arousal (theta and alpha-3 bands). • Anterior regions of the left hemisphere (theta and alpha-3 bands) : valence dimension. • Are therereallyhemisphericasymmetries ? There is no physiological facts which assert the existence of an asymmetry in the emotional expression. Seminar BCI - Presentation – Adrien Cognée – March 12th 2009

  17. Thanks

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