Central command-related increases in blood velocity of anterior cerebral artery and prefrontal oxygenation at the onset of voluntary tapping

• Published in: American journal of physiology. Heart and circulatory physiology Vol. 321; no. 3; pp. H518 - H531
• Main Authors: Matsukawa, Kanji, Asahara, Ryota, Uzumaki, Minami, Hashiguchi, Yoshiki, Ishii, Kei, Wang, Jijia, Smith, Scott A.
• Format: Journal Article
• Language: English
• Published: Bethesda American Physiological Society 01.09.2021
• Subjects: Blood flow; Cross correlation; Frontal lobe; Hemoglobin; Motor task performance; Muscles; Oxygenation; Prefrontal cortex; Time lag; Vasodilation; Velocity
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.00062.2021

Anterior cerebral artery blood velocity and vascular conductance index along with prefrontal oxygenated-hemoglobin concentration all increased at the onset of finger tapping, peaking immediately after tapping onset, as long as tapping was arbitrarily started. Positive cross correlation and linear regression between the increases in ACA BV and prefrontal Oxy-Hb were significant in 67%–75% of subjects. Active vasodilatation of the ACA vascular bed occurs with arbitrary tapping onset and contributes to increased ACA BV and prefrontal oxygenation. The anterior cerebral artery (ACA) supplies blood predominantly to the frontal lobe including the prefrontal cortex. Our laboratory reported that prefrontal oxygenated-hemoglobin concentration (Oxy-Hb) increased before and at exercise onset, as long as exercise is arbitrarily started. Moreover, the increased prefrontal oxygenation seems independent of both exercise intensity and muscle mass. If so, mean blood velocity of the ACA (ACA BV ) should increase with “very light motor effort,” concomitantly with the preexercise and initial increase in prefrontal Oxy-Hb. This study aimed to examine the responses in ACA BV and vascular conductance index (ACA VCI ) of the ACA as well as prefrontal Oxy-Hb during arbitrary or cued finger tapping in 12 subjects, an activity with a Borg scale perceived exertion rating of 7 (median). With arbitrary start, ACA BV increased at tapping onset (14 ± 9%) via an elevation in ACA VCI . Likewise, prefrontal Oxy-Hb increased at the onset of tapping with a time course resembling that of ACA BV . A positive cross correlation between the initial changes in ACA BV and prefrontal Oxy-Hb was found significant in 67% of subjects, having a time lag of 2 s, whereas a positive linear regression between them was significant in 75% of subjects. When tapping was forced to start by cue, the initial increases in ACA BV , ACA VCI , and prefrontal Oxy-Hb were delayed and blunted as compared with an arbitrary start. Thus, active vasodilatation of the ACA vascular bed occurs at tapping onset, as long as tapping is arbitrarily started, and contributes to immediate increases in blood flow and prefrontal oxygenation. NEW & NOTEWORTHY Anterior cerebral artery blood velocity and vascular conductance index along with prefrontal oxygenated-hemoglobin concentration all increased at the onset of finger tapping, peaking immediately after tapping onset, as long as tapping was arbitrarily started. Positive cross correlation and linear regression between the increases in ACA BV and prefrontal Oxy-Hb were significant in 67%–75% of subjects. Active vasodilatation of the ACA vascular bed occurs with arbitrary tapping onset and contributes to increased ACA BV and prefrontal oxygenation.