Author/Editor		Demarin, Vida
Title		Influence of cognitive stimulation on blood flow through the middle cerebral artery
Translated title		Vpliv kognitivne stimulacije na krvni pretok v srednji možganski arteriji
Type		članek
Source		Med Razgl
Vol. and No.		Letnik 38, št. Suppl 5
Publication year		1999
Volume		str. 11-20
Language		eng
Abstract		The Transcranial Doppler Sonography (TCD) method was used in order to examine blood flow velocities in the middle cerebral artery (MCA), bilaterally, during selective stimulation of cognitive centres by specific groups of mental tasks. The study comprised a homogeneous sample of 66 right-handed female subjects. The subjects performed four 90-second tasks and had five 42-second rest phases. Two verbal tasks were presumed to be processed predominantly by the left hemisphere and spatial and visual perception tasks by the right one. TCD monitoring was performed during rest and during the performance of cognitive tasks, in alternation. During cognitive stimulation, blood flow velocities in the middle cerebral artery were found to be bilaterally increased. A statistically significant greater increase in blood flow velocities through the right MCA was found during stimulation of cortical centres in the right cerebral hemisphere. And vice versa: a statistically significant greater increase of blood flow velocities in the left MCA was found during stimulation of cortical centres on the left side of the brain, compared to the contralateral artery. The time variation of blood flow velocity during a cognitive activity showed an initial increase to maximum after approximately 4-6.5 seconds and then a rapid decrease in velocity at approximately 14-25 seconds. A steady state was reached after approximately 25-40 seconds. Our results suggest that selective stimulation of cognitive centres causes hemispheric lateralisation of blood flow velocities. This method therefore enables a selective study of local vasomotor reactivity, which is an important contribution to the tunctional transcranial Doppler diagnosis.
Summary		Za študij hitrosti krvi v obeh srednjih možganskih arterijah med selektivnim draženjem kognitivnih centrov s specifično izbranimi skupinami mentalnih nalog je bila uporabljena transkranialna Dopplerjeva sonografija. Študijska skupina je bila homogena, v njej je sodelovalo 66 žensk. Vse so bile desničarke. Preiskovanke so opravljale naloge, ki so trajale 90 minut, med njimi je bilo pet počitkov, dolgih 42 sekund. Uporabili smo dve besedni nalogi, ki ju nadzira predvsem leva možganska polobla, in prostorske ter vidne naloge, ki jih nadzira desna možganska polobla. Ugotovili smo, da se med kognitivno stimulacijo hitrost krvi poveča v obeh srednjih možganskih arterijah. Med draženjem kognitivnih centrov v desnem delu možganske skorje smo ugotovili statistično pomembno povečanje hitrosti krvi v desni srednji možganski arteriji. Med draženjem kognitivnih centrov v levi možganski polobli smo zabeležili statistično pomembno povečanje hitrosti krvi v levi srednji možganski arteriji glede na desno. Med kognitivnim draženjem se hitrost krvi sprva poveča, doseže največjo vrednost po 4 do 6,5 sekundah in se nato naslednjih 14 do 25 sekund hitro zmanjšuje, ravnovesno stanje pa doseže po 25-40 sekundah. Rezultati kažejo, da draženje kognitivnih centrov povzroči lateralizacijo hitrosti krvi. Z omenjeno metodo je mogoče selektivno preučevati lokalizirana dogajanja v avtoregulaciji možganskega pretoka, kar predstavlja pomemben prispevek v funcionalni transkranialni doplerski diagnostiki.
Descriptors		CEREBRAL ARTERIES BLOOD FLOW VELOCITY COGNITION ADULT BRAIN ULTRASONOGRAPHY, DOPPLER, TRANSCRANIAL