The relationship between the characteristics of brain energy metabolism and psychophysiological indicators is especially pronounced in transitional periods of development and involution. During aging, brain activity occurs under conditions of energy deficiency due to the gradual decrease in cerebral blood flow, breach of the BBB, changes in enzyme activity and damage to mitochondria. In many cases, to ensure mental processes, additional ways of obtaining energy are used, similar to those used for stress: glycolysis increases, ketone bodies are used as an energy substrate, etc. This is accompanied by a decrease in intracellular pH in neurons, which, for its part, affects on brain activity and the flow of mental processes .
To study the effect of changes in cerebral energy metabolism in old age on the state of cerebral functions, we conducted a study of the brain SCP and psychological characteristics in 28 mentally healthy women aged 72-93 years old who are in a nursing home. They recorded SCP in 17 leads according to the scheme 10-20. Held also testing of long-term and short-term memory, leading affect (normal or depressed) and social activity. The long-term memory of past events associated with significant biographical facts for the subjects was ranked on a five-point scale. The state of short-term memory was assessed on a four-point scale. Activity was ranked on a three-point scale, taking into account the performance by women of the necessary actions to maintain order in their room, social contacts and social activities. It was also assessed to what extent the surveyed live with the concerns of the present day or are immersed in the past (the so-called situation shift into the past).
Since many brain structures are involved in providing any of the above mental functions, to establish the very fact of the connection of these functions with cerebral energy exchange, the multiple correlation coefficient was determined, which relates many of the characteristics of SCP to certain mental functions .
Multiple correlation coefficients between psycho-physiological characteristics and SCP parameters
The table shows that the multiple correlation coefficients between the set of SCP parameters and psychological characteristics are highly reliable. To find out how the peculiarities of energy metabolism, reflected in the SCP indices, affect the psychological characteristics of the examined women, single-factor analysis of variance was performed.
There is a range of SCP values at which mental functions are implemented in an optimal way. Short-term memory was better with an average SCP of less than 12 mV than with a higher potential level, as well as with SCP in the right temporal region more than -8 mV and less than 14 mV (Fig. 10.9). It may be thought that in individuals with high SCP values in the brain as a whole or in the right temporal region there is a decrease in cerebral pH, indicating latent hypoxia or latent neurodegeneration, which is naturally accompanied by deterioration of short-term memory. Short-term memory in three groups of test subjects of old age with different values of SCP in the right temporal region.
Long-term varied depending on the size of the local SCP in the right parietal and left occipital regions .
Long-term memory was higher in individuals with low local potentials in the occipital region and high in the parietal.
Long-term memory and local SCP in the occipital region of older subjects.
On the abscissa scale – the assessment of long-term memory in points (the highest long-term memory corresponds to the highest score). Vertical axis – the value of the SCP
Mental activity and a shift in the situation of the past were associated with the magnitude of the average SCP .