Figure 3 - uploaded by Alina Studenova
Content may be subject to copyright.
The difference in the strength of alpha amplitude modulation correlates with the difference in P300 amplitude. A. Alpha amplitude envelope sorted into 5 bins according to the depth of modulation in the poststimulus window. The bins were the following: (66, -25), (-25, -37), (-37, -47), (-47, -58), (-58,-89) % change. Here, -100% corresponds to the deepest modulation, and 0% to the absence of a change in the amplitude. B. P300 responses are sorted into the corresponding bins. C. The spatio-temporal t-test reveals clusters of significant differences between the two most extreme bins-bin 1 and bin 5. The topography of t-statistics is sampled at 500 ms. The significant electrodes at this time point are marked with "x".
Source publication
Evoked responses and oscillations represent two major electrophysiological phenomena in the human brain yet the link between them remains rather obscure. Here we show how most frequently studied EEG signals: the P300-evoked response and alpha oscillations (8–12 Hz) can be linked with the baseline-shift mechanism. This mechanism states that oscillat...
Contexts in source publication
Context 1
... illustrate the relation even further, we filtered the ER in low frequency up to 3 Hz. Figure 2A on the left demonstrates the evolution of averaged time courses of ER at the Pz electrode, and Figure 2A on the right is the same but for the alpha amplitude envelope (see also Figure S3 for the whole-head time courses). This figure clearly shows a similarity in the temporal evolution for both types of signals. ...
Context 2
... to a strong drop in the poststimulus amplitude in comparison to prestimulus, while a value closer to 0 % corresponds to the absence of change in the amplitude, and a value larger than 0 % corresponds to the increase in the amplitude in the poststimulus window. The different alpha amplitude dynamics correlated with P300 amplitude, such that for participants with a stronger alpha amplitude modulation, the amplitude of P300 was higher than for participants with weak amplitude modulation ( Figure 3A,B). As predicted by BSM, a smaller alpha amplitude modulation will generate an ER with a smaller amplitude. ...
Context 3
... total number of participants in each bin is 446. The t-test between the most extreme bins demonstrates a significant spatio-temporal cluster in the posterior region spanning electrodes CP6, P3, P4, P7, Pz, O1, O2, PO9 ( Figure 3C). Here, t-values are negative, meaning that P300 that coincides with small alpha amplitude attenuation is significantly smaller in its amplitude than P300 that coincides with the largest alpha amplitude attenuation. ...
Context 4
... t-values are negative, meaning that P300 that coincides with small alpha amplitude attenuation is significantly smaller in its amplitude than P300 that coincides with the largest alpha amplitude attenuation. The cluster within the earlier window (100-200 ms) over central regions ( Figure 3C) possibly reflects the previously shown effect of prestimulus alpha amplitude on earlier ERs ( Brandt et al., 1991, Babiloni et al., 2008) which potentially may be also a manifestation of BSM. Here, -100% corresponds to the deepest modulation, and 0% to the absence of a change in the amplitude. ...
Context 5
... the target tone presentation required participants to press the button, and as with any movement, the button press was also accompanied by oscillatory changes in the alpha (mu) frequency range ( Pfurtscheller et al., 1999, Nikulin et al., 2008. In line with this assumption, we found a positive correlation between P300 and alpha amplitude envelope around C3-C4 electrodes ( Figure 2B) and negative P300 amplitudes over the same region ( Figure 4A; also see Figure S3A where the P300 time courses have negativity over central electrodes), which indicates that there is a motor-related component of ER ( Salisbury et al., 2001), with typically observed negative polarity that may have originated from a source of alpha (mu) oscillations relating to motor activity. Hence, depending on the task, there might be other changes in rhythmic activity that occlude or completely hinder the identification of oscillations that are related to the ER in question. ...
Similar publications
Evoked responses and oscillations represent two major electrophysiological phenomena in the human brain yet the link between them remains rather obscure. Here we show how most frequently studied EEG signals: the P300-evoked response and alpha oscillations (8–12 Hz) can be linked with the baseline-shift mechanism. This mechanism states that oscillat...
