Evoked brain stem and SCP potentials

Let us briefly consider the relationship between the indices of auditory evoked potentials of the brain stem (SVPMS) and SCP.

SVPMS is a sequence of seven positive short-patent components that occur in the structures of the brain stem during auditory stimulation. The latent period of the first component is 1.5-1.8 ms, the seventh is 8.1–9.5 ms, the amplitude of the components is no more than 1 μV. The first component arises in connection with the activity of the auditory nerve, the subsequent ones are due to the activity of the structures of the brain stem, and the higher the serial number of the component, the higher is the structure in the brain stem that participates in its generation. Thus, the origin of the V component is associated with the lower hillocks of the quadrilateral, and the VII with the thalamocortical projections (K.Ya. Ogleznev et al., 1982).

We recorded the SVPMS on a specialized device for recording the evoked potentials of the Neuropack-2. Hearing stimulation was performed using headphones, through which clicks with a frequency of 10 Hz and intensity 60 dB above the hearing threshold were applied to both ears of the subject. Active electrodes were placed over the vertex, the reference electrodes were placed on the ear lobe. The number of averages was 2048, the epoch of analysis was 10 ms. The studies were conducted on 24 young and middle-aged subjects (average 34.3 + 1.4 years), as well as in a group of 14 elderly subjects (average 59.0 + 1.6 years).

First, we consider the multiple correlation between the characteristics of SVPMS and UPP, detected in healthy young and middle-aged subjects (Table 8.8).

Multiple correlation coefficients, when the amplitude characteristics of the SVPMS are independent variables, and the SCP – dependent.

In the reverse situation, when the set of SCPP indicators was considered as an independent variable, and the parameters of SVPMS as an independent variable, the number and value of reliable coefficients of multiple correlation are significantly lower (Table 8.9). As well as in the case of the ratio of UPP with visual evoked potentials, this indicates a greater dependence, at least normal, of the energy processes on the functional activity of the brain, than energy exchange on information processes.

Multiple correlation coefficients between the characteristics of the SCP and the amplitudes of the SVPMS when the set of characteristics of the SCP is considered as a set of independent variables

A5 d, s is the amplitude of the 5th component of the SVPMS to the right and to the left, respectively. The rest of the notation is the same .

It is also of interest to analyze the pairwise correlations between the characteristics of the UPP and the SVPMS. Elderly subjects have significant correlations significantly more than at a young age, although the nature of the relationship is in principle.

As can be seen , the parameters of SCP in unipolar leads, as a rule, are associated with a positive correlation with the amplitude characteristics of the SMPMS, and a negative correlation with the latent periods of this type of evoked potentials. In this sample, there was no correlation between the UPP and SVPMS parameters with age, and the detected relationship between the UPP and SVPMS cannot be mediated by the age factor. The increase in amplitude and decrease in the latent periods of SVPMS reflects the activation of the brain stem. So, according to J Majkowski et al. (1983), when nonspecific activation occurs, the latent periods of SVPMS are shortened and their amplitudes increase, and vice versa as the functional activity of the brain decreases, the latencies of SVPMS increase and their amplitude decreases. This is apparently due to the fact that auditory neurons and the reticular The neurons of the brain stem are closely related to each other. On the other hand, the reticular formation of the trunk is involved in the regulation of the intensity of cerebral energy processes in general. Therefore, the found dependence confirms the idea that the activation of the brain stem leads to an increase in cerebral energy metabolism, which is reflected in an increase in UPP.

So, the correlation analysis revealed the following basic patterns that determine the relationship between the parameters of evoked potentials and the UPP of the brain.

1. Changes in SVPMS, reflecting the increased excitability of the brain stem, is accompanied by the activation of large sections of the cortex, the intensification of energy metabolism in these areas and, accordingly, an increase in AMR. The amplitude of the components of the VEP generated in the cerebral cortex and SCP are in most cases related to reciprocal relationships, which obviously reflect the effect of changes in acid-base balance in the brain on the functional activity of neurons.

2. The correlation between SCP and EP of different genesis is not limited by the relationship between the functional activity of brain structures involved in the generation of evoked potentials and their energy metabolism. Correlation dependence occurs between the parameters of the SGP and SCP registered in different areas of the brain, which links information and energy processes in the nervous system into a single functional state. This gives reason to talk about a single energy-information state of the brain.

local_offerevent_note July 29, 2019

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