International Union for Circumpolar Health Ministry of Public Health and Social Development of RF Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Sciences Medical Polar Fund “Science” The Northern Forum

Abstracts

Ecology and adaptation (medical ecology)

At present the majority of authors indicate that integral evaluation of pared sensorimotor variables in humans is more closely related to functional cerebral activity than determination of right-handedness or left-handedness, i.e. description of people as right- or left-handers. This approach makes possible to recognize individuals with different degree of lateralization from a complete left-side profile of sensorimotor asymmetry to a complete right-side profile. It appeared that most people are characterized by the mixed type of asymmetry. Such an assessment of functional asymmetry profile allows to reveal some peculiarities of adaptation to the extreme climato-geographic conditions, that are determined by different involvement of cerebral hemispheres in the regulation of the process of adaptation

The process of adaptation is associated with realization of the principle of maximum when the abilities of both cerebral hemispheres are required. The right hemisphere is known to be subjected to the feedback control to a lesser degree than the left one. Being more autonomous, it is selectively involved in the assessment of uncertain environment and prognosis of improbable events. At the same time, the constant consequence of controlling influences under usual conditions is best provided by the left hemisphere.

Using the method of transcranial doplerography the rate of linear blood flow in cerebral hemispheres of the subjects with absolute left or right laterality has been analyzed under conditions of urgent adaptation to the oxygen deficiency. This experimental approach has been chosen since similar adaptive changes in brain regulatory mechanisms may occur in the populations living under conditions of hypoxia, for example, hypoxic hypoxia in the mountain regions or hypoxia to cold in the North.

Inhalation of a gas mixture, containing only 10% of oxygen and 90% of nitrogen produced an increase in the linear blood flow in both hemispheres in all groups of subjects. However, the observed changes were more pronounced in the hemispheres of the left-handed subjects. Moreover, after prolonged exposure to the gas mixture decreasing blood oxygenation by 80% the blood flow rate was significantly reduced in the left hemisphere of the subjects with the right asymmetry profile compared to the group with the left asymmetry parameters.

Adaptation of subjects with the right-side asymmetry preference is associated with alternate activation of cerebral hemispheres with the prominent role of the right hemisphere in providing the homeostasis. Individuals with the left or symmetric profiles of functional asymmetry would have better abilities to adapt under extreme conditions. The process of adaptation under comfort climato-geographic and stereotyped conditions would be more efficient in the subjects characterized by the right profile of sensorimotor asymmetry.

Note. Abstracts are published in author's edition

© 1996-2005, Siberian Branch of Russian Academy of Sciences, Novosibirsk
Last update: 06-Jul-2012 (11:52:05)