Аннотация:Mental activity is accompanied by the activation of the autonomic nervous system (ANS), and may cause
mental stress and pronounced changes in brain energy metabolism in patients with mild cognitive
impairment (MCI).
132 MCI patients, men and women, were examined during the performance of cognitive tests:
proofreading, verbal fluency and verbal memory Luria test. Blood pressure, heart rate, Doppler measure of
linear blood flow velocity (LBV) in cerebral arteries, DC potentials of the brain were recorded. Glucose in
blood, cortisol and insulin in saliva were examined before and after the performance of cognitive tests.
During the performance of cognitive tests significant increase in blood pressure and heart rate, as well as
the DC potentials in different area of the head was observed. After the tests the level of glucose showed a
decrease (-0.68+/-0.2 mmol/l), and the concentration of cortisol and insulin showed a significant increase
(11.6+/-3.3 nmol/l; 4.7+/-1.2 pmol/l). Lowering of blood glucose level was associated with worse
performance of the proofreading test (r=0.44, p=0.001) and better performance of verbal fluency test
(r=0.28, p=0.04).
Better performance of verbal fluency test correlated with the increasing of heart rate during the test
(r=0.41; p=0.001). The increase of DC potential in left temporal area was associated with better verbal
memory in Luria’s test (F=6.9, p=0.01). LVB in the main cerebral arteries of the head was not significantly
changed during cognitive tasks. However the increase of LVB during the test in right middle cerebral artery
was associated with worse performance of proofreading test (F=6.6; p=0.02).
The results suggest that the performance of different cognitive tests is accompanied by similar pattern of
ANS reactivity. However successful performance of cognitive tests correlated with different characteristics
of ANS reactivity, this may be due to the activation of different cortical and ANS structures during cognitive
processing.