Consideration of the relationship between EEG and SCP will begin with the topographic distribution of these types of bioelectric activity. In healthy subjects, SCP is positive in all areas of the head, SCP is lower in the frontal region, and higher in the central, than in other leads . In more detail, the nature of the distribution of SCP over the surface of the head is normally described above .
UCP of the brain in healthy subjects in a state of calm wakefulness
Below – UPP color scale.
In healthy subjects, the magnitude of the relative spectral power of the alpha rhythm is higher than that of other EEG frequency bands .
Relative spectral power of EEG frequency ranges in healthy subjects in a state of calm wakefulness.
Right – color scale relative spectral power
A positive correlation was found between the relative spectral power of alpha activity in the occipital region and the UPP in the same brain region ( r = 0.66; p = 0.008) (Fig. 8.3). A similar in sign, but less close relationship was found between the average SCP and the relative spectral power of the EEG alpha activity in the occipital region ( r = 0.54; p = 0.039).
The correlation between the relative spectral power of the alpha rhythm in the occipital region and the SCP in the same section of the head in healthy subjects in a state of calm wakefulness.
On the ordinate axis – the value of the UPP, on the abscissa axis – the relative spectral power in arbitrary units. Oz – occipital lead
SCP in the central region correlated with the relative spectral power of beta2 activity in the same brain region ( r = 0.59; p = 0.02), and also with the average relative power of beta2 for all leads ( r = 0.56; p = 0.29).
The SCP in the occipital region was associated with a negative correlation with the spectral power of theta and delta activities in this section ( r = -0.68; p = 0.005 and r = –0.63 p = 0.011, respectively) (Fig. 8.4; 8.5 ). ATS averaged over all leads correlated with the relative spectral power of theta activity in the occipital region ( r = -0.77; p = 0.001), and also with the relative spectral power of theta activity for all leads ( r = -0.68; p = 0.006).
Correlation between the relative spectral power of theta activity in the occipital region and the SCP in the same head section in healthy subjects in a state of calm wakefulness
Correlation between the relative spectral power of the delta activity in the occipital region and the SCP in the same section of the head in healthy subjects in a state of calm wakefulness
So, in healthy subjects in a state of calm wakefulness, an increase in SCP correlates with an increase in the relative spectral power of alpha and beta activity and with a decrease in the spectral power of slow-wave activity of theta and delta bands.
The increase in the relative power of the alpha and beta rhythm with a decrease in the relative power of the theta and delta bands reflects an increase in the functional activity of the brain, and the increase in SCP is associated with an increase in cerebral energy metabolism. Therefore, the nature of the correlation between EEG and UPP suggests that normally an increase in the functional activity of the brain is associated with an increase in cerebral energy metabolism. This relationship seems to be logical, since the activation of the brain increases glucose metabolism, as a result of which the concentration of acid metabolic products, carbonic acid and lactate, resulting from aerobic and anaerobic glucose decomposition, increases in nerve cells and cerebrospinal fluid.Therefore, when enhancing the functional activity of the brain, the potential difference of the BBB and, accordingly, the SCP on the surface of the head increase.