Studies in 20 healthy right-handed subjects analyzed evoked EEG synchronization and desynchronization in the delta, theta1, theta2, alpha1, alpha2, beta1, beta2, beta3, and gamma ranges in response to sequential presentation of stimuli from the International Affective Picture System (IAPS) with low, medium, and high emotional activation impact. Each signal presentation was accompanied by subjective scaling of the extent of its emotional impact. EEG traces were recorded in 62 channels as signals were presented. These experiments showed that the degree of emotional impact of the signal was significantly associated with increases in evoked synchronization in the delta, theta1, theta2, beta1, beta3, and gamma ranges and with the effects of combined changes in evoked synchronization and desynchronization in the alpha2 frequency range. The interhemisphere distribution of evoked changes in power provided evidence that not only the posterior areas of the right hemisphere were involved in analyzing the emotional significance of images, as indicated by changes in evoked theta1 and theta2 synchronization and alpha2 desynchronization, but also the anterior areas of the left hemisphere, as indicated by changes in evoked theta2 synchronization. From the standpoint of affective chronometry, the earliest discrimination of the emotional content of stimuli, regardless of the sign of the emotion, occurred in the lower theta range and was seen at 0-600 msec after the start of stimulus presentation. This process was delayed 600-1000 msec in the theta2, alpha2, and gamma ranges.
The Petaflops supercomputer "Zhores" recently launched in the "Center for Computational and Data-Intensive Science and Engineering" (CDISE) of Skolkovo Institute of Science and Technology (Skoltech) opens up new exciting opportunities for scientific discoveries in the institute especially in the areas of data-driven modeling, machine learning and artificial intelligence. This supercomputer utilizes the latest generation of Intel and NVidia processors to provide resources for the most compute intensive tasks of the Skoltech scientists working in digital pharma, predictive analytics, photonics, material science, image processing, plasma physics and many more. Currently it places 6 th in the Russian and CIS TOP-50 (2018) supercomputer list. In this article we summarize the cluster properties and discuss the measured performance and usage modes of this scientific instrument in Skoltech.
Event-related desynchronization (ERD) and synchronization (ERS) in the individually defined theta, alpha-1, alpha-2, and alpha-3 frequency bands were measured in 22 healthy subjects (Ss) in response to neutral (Neut), emotionally positive (Pos), and negative (Neg) IAPS stimuli. The 62-channel EEG, facial EMG and ECG were simultaneously recorded while subjects viewed sequentially presented pictures and subjectively rated them after each presentation. The obtained findings indicate that differences induced by pictures varying in emotional valence are associated mainly with increased theta and alpha-3 synchronization activity and anterior hemispheric asymmetries. In the anterior temporal leads theta ERS revealed a significant valence by hemisphere interaction showing relatively greater right hemisphere theta ERS for Neg and left hemisphere ERS for Pos stimuli in the time window of 100-700 ms post-stimulus, whereas in the alpha-3 band Neg stimuli induced lateralized time-dependent left hemisphere ERS increased in the time window of 800-1200 ms, were not observed for Neut and Pos stimuli. The obtained results along with earlier observations on EEG correlates of affective processing challenge the notion that affective anterior hemispheric asymmetries are mainly sensitive to wide alpha frequency band. Frequency and time dependence of anterior hemispheric asymmetries in emotional valence discrimination is emphasized.
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