Background: High altitude sojourn challenges blood flow regulation in the brain, which may contribute to cognitive dysfunction. Neurovascular coupling (NVC) describes the ability to increase blood flow to working regions of the brain. Effects of high altitude on NVC in frontal regions undergoing cognitive activation are unclear but may be relevant to executive function in high-altitude hypoxia. This study sought to examine the effect of incremental ascent to very high altitude on NVC by measuring anterior cerebral artery (ACA) and middle cerebral artery (MCA) hemodynamic responses to sustained cognitive activity. Materials and Methods: Eight adults (23 ± 7 years, four female) underwent bilateral measurement of ACA and MCA mean velocity and pulsatility index (PI) through transcranial Doppler during a 3-minute Stroop task at 1400, 3440, and 4240 m. Results: Resting MCA and ACA PI decreased with high-altitude hypoxia (p < 0.05). Cognitive activity at all altitudes resulted in similar increases in MCA and ACA mean velocity, and decreases in ACA and MCA PI (p < 0.05 for MCA, p = 0.07 for ACA). No significant altitude-by-Stroop interactions were detected, indicating NVC was stable with increasing altitude. Conclusions: Ascent to very high altitude (4240 m) using an incremental profile that supports partial acclimatization does not appear to disturb (1) increases in cerebral blood velocity and (2) reductions in pulsatility that characterize optimal NVC in frontal regions of the brain during cognitive activity.
Background: High altitude sojourn challenges blood flow regulation in the brain, which may contribute to cognitive dysfunction. Neurovascular coupling (NVC) describes the ability to increase blood flow to working regions of the brain. Effects of high altitude on NVC in frontal regions undergoing cognitive activation are unclear but may be relevant to executive function in high-altitude hypoxia. This study sought to examine the effect of incremental ascent to very high altitude on NVC by measuring anterior cerebral artery (ACA) and middle cerebral artery (MCA) hemodynamic responses to sustained cognitive activity. Materials and Methods: Eight adults (23 ± 7 years, four female) underwent bilateral measurement of ACA and MCA mean velocity and pulsatility index (PI) through transcranial Doppler during a 3-minute Stroop task at 1400, 3440, and 4240 m. Results: Resting MCA and ACA PI decreased with high-altitude hypoxia (p < 0.05). Cognitive activity at all altitudes resulted in similar increases in MCA and ACA mean velocity, and decreases in ACA and MCA PI (p < 0.05 for MCA, p = 0.07 for ACA). No significant altitude-by-Stroop interactions were detected, indicating NVC was stable with increasing altitude. Conclusions: Ascent to very high altitude (4240 m) using an incremental profile that supports partial acclimatization does not appear to disturb (1) increases in cerebral blood velocity and (2) reductions in pulsatility that characterize optimal NVC in frontal regions of the brain during cognitive activity.
Entities:
Keywords:
cerebral hemodynamics; high altitude trekking; hypoxia; neurovascular coupling; pulsatility
Authors: Garrett L Peltonen; John W Harrell; Benjamin P Aleckson; Kaylie M LaPlante; Meghan K Crain; William G Schrage Journal: Am J Physiol Regul Integr Comp Physiol Date: 2016-05-25 Impact factor: 3.619
Authors: Aaron A Phillips; Franco Hn Chan; Mei Mu Zi Zheng; Andrei V Krassioukov; Philip N Ainslie Journal: J Cereb Blood Flow Metab Date: 2015-11-24 Impact factor: 6.200
Authors: Andrew W Subudhi; Nicolas Bourdillon; Jenna Bucher; Christopher Davis; Jonathan E Elliott; Morgan Eutermoster; Oghenero Evero; Jui-Lin Fan; Sonja Jameson-Van Houten; Colleen G Julian; Jonathan Kark; Sherri Kark; Bengt Kayser; Julia P Kern; See Eun Kim; Corinna Lathan; Steven S Laurie; Andrew T Lovering; Ryan Paterson; David M Polaner; Benjamin J Ryan; James L Spira; Jack W Tsao; Nadine B Wachsmuth; Robert C Roach Journal: PLoS One Date: 2014-03-21 Impact factor: 3.240