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Time-dependent cortical asymmetries induced by emotional arousal EEG analysis of event-related synchronization and desynchronization in Individually defined.

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Presentation on theme: "Time-dependent cortical asymmetries induced by emotional arousal EEG analysis of event-related synchronization and desynchronization in Individually defined."— Presentation transcript:

1 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. Reva2001 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) Seminar BCI - Presentation – Adrien Cognée – March 12th 2009 Pleasure Arousal Dominance

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

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12 Results

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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 theta synchronization in the time period of ms post-stimulus. In the alpha-1 and alpha-3 bands, discriminative process : ms. 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 hemispheric asymmetries 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 there really hemispheric asymmetries ? 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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