Changes of circulatory-metabolic indices and skull biomechanics with brain activity during aging.

The cerebral blood flow values used in experimental and clinical investigations as the informative criteria for brain blood supply are often misleading. The correlation between the cerebral blood supply and brain function is not proven in all cases. An increase of brain activity is known to be accompanied by a rise of blood flow in activated regions, while a decreased activity results in a decreased blood flow. This demonstrates the close correlation between the brain blood supply and its activity. Such a correlation had not been noted in the age-dependent decrease of cerebral blood flow, suggesting the existence of special age-related mechanisms that develop with age to maintain brain metabolism. The biomechanical properties are of special significance as predicted in the early 20th century. Only recently were they validated by the simultaneous recording of Transcranial Dopplerogram and Rheoencephalogram with in-depth analysis focused on single cardiac cycles. Functioning of the intracranial blood and cerebrospinal fluid dynamics was integrated with a special physiological test "Prognosis-2" to measure brain cognitive function. Correlation was demonstrated with the circulatory-metabolic state of brain activity, especially in people with changing cognitive function. The data supports a conceptual model of adequate circulatory-metabolic supply of brain activity, showing the functional unity, which follows from integration of the mentioned systems.

Role of saccadic eye movements in cognitive processes.

Using specially developed tests we studied the processes of prediction of the appearance of letter sequences and simultaneously recorded saccadic eye movements. It was found that the number of saccades increases with increasing test complexity, which is probably related to the necessity to process more complex and capacious information.

Neurophysiological mechanisms of the attention disturbance in children with learning difficulties.

The features of orientation reaction (OR) and the background EEG were investigated with the purpose of studying the neurophysiological mechanisms of the disturbance of voluntary attention in children aged 6.5-9 years with learning difficulties caused by delayed mental development (DMD). A decrease in the expressivity of components of the OR as compared with the norm, discovered in a situation of involuntary attention against a background of insufficiently developed cortical rhythmicity in the alpha range, was compensated for given an increase in the significance of the stimuli. These facts support the hypothesis of a deficit in regulatory corticofugal influences in children with DMD. The inadequacy of the engagement of central regions of the cortex characteristic of children with DMD in the realization of OR in a situation of directed attention can be regarded as a reflection of disturbances of the integrative activity of the brain.