[Hemodynamics (general and cerebral) and mental activity under normal conditions]

Interrelations between the mental work efficiency and changes in total and cerebral hemodynamics during mental activity are considered. Five subgroups of the efficiency are distinguished. Changes in the vegetative reactions considerably differ in the type as well. Basic four types of such reactions are distinguished with allowance for changes in the character of minute blood circulation volume and cerebral blood flow. Comparison of changes in the efficiency of the activity with vegetative changes shows that in the process of the mental activity the vegetative changes are determined by interrelation between the intensity of the mental activity and its efficiency. It was concluded that the higher the activity efficiency, the lower the mental intensity and changes in the total and cerebral hemodynamics and, vice versa.