TY - JOUR
T1 - Dynamic cerebral autoregulation during cognitive task
T2 - Effect of hypoxia
AU - Ogoh, Shigehiko
AU - Nakata, Hiroki
AU - Miyamoto, Tadayoshi
AU - Bailey, Damian Miles
AU - Shibasaki, Manabu
PY - 2018/6/1
Y1 - 2018/6/1
N2 - Changes in cerebral blood flow (CBF) subsequent to alterations in the partial pressures of oxygen and carbon dioxide can modify dynamic cerebral autoregulation (CA). While cognitive activity increases CBF, the extent to which it impacts CA remains to be established. In the present study we determined whether dynamic CA would decrease during a cognitive task and whether hypoxia would further compound impairment. Fourteen young healthy subjects performed a simple Go/No-go task during normoxia and hypoxia (inspired O2 fraction 12%), and the corresponding relationship between mean arterial pressure (MAP) and mean middle cerebral artery blood velocity (MCA Vmean) was examined. Dynamic CA and steady-state changes in MCA V in relation to changes in arterial pressure were evaluated with transfer function analysis. While MCA Vmean increased during the cognitive activity (P 0.001), hypoxia did not cause any additional changes (P 0.804 vs. normoxia). Cognitive performance was also unaffected by hypoxia (reaction time, P 0.712; error, P 0.653). A decrease in the very low- and low-frequency phase shift (VLF and LF; P 0.021 and P 0.01) and an increase in LF gain were observed (P 0.037) during cognitive activity, implying impaired dynamic CA. While hypoxia also increased VLF gain (P 0.001), it failed to cause any additional modifications in dynamic CA. Collectively, our findings suggest that dynamic CA is impaired during cognitive activity independent of altered systemic O2 availability, although we acknowledge the interpretive complications associated with additional competing, albeit undefined, inputs that could potentially distort the MAP-MCA Vmean relationship. NEW & NOTEWORTHY During normoxia, cognitive activity while increasing cerebral perfusion was shown to attenuate dynamic cerebral autoregulation (CA) yet failed to alter reaction time, thereby questioning its functional significance. No further changes were observed during hypoxia, suggesting that impaired dynamic CA occurs independently of altered systemic O2 availability. However, impaired dynamic CA may reflect a technical artifact, given the confounding influence of additional inputs that could potentially distort the mean arterial pressure-mean middle cerebral artery blood velocity relationship.
AB - Changes in cerebral blood flow (CBF) subsequent to alterations in the partial pressures of oxygen and carbon dioxide can modify dynamic cerebral autoregulation (CA). While cognitive activity increases CBF, the extent to which it impacts CA remains to be established. In the present study we determined whether dynamic CA would decrease during a cognitive task and whether hypoxia would further compound impairment. Fourteen young healthy subjects performed a simple Go/No-go task during normoxia and hypoxia (inspired O2 fraction 12%), and the corresponding relationship between mean arterial pressure (MAP) and mean middle cerebral artery blood velocity (MCA Vmean) was examined. Dynamic CA and steady-state changes in MCA V in relation to changes in arterial pressure were evaluated with transfer function analysis. While MCA Vmean increased during the cognitive activity (P 0.001), hypoxia did not cause any additional changes (P 0.804 vs. normoxia). Cognitive performance was also unaffected by hypoxia (reaction time, P 0.712; error, P 0.653). A decrease in the very low- and low-frequency phase shift (VLF and LF; P 0.021 and P 0.01) and an increase in LF gain were observed (P 0.037) during cognitive activity, implying impaired dynamic CA. While hypoxia also increased VLF gain (P 0.001), it failed to cause any additional modifications in dynamic CA. Collectively, our findings suggest that dynamic CA is impaired during cognitive activity independent of altered systemic O2 availability, although we acknowledge the interpretive complications associated with additional competing, albeit undefined, inputs that could potentially distort the MAP-MCA Vmean relationship. NEW & NOTEWORTHY During normoxia, cognitive activity while increasing cerebral perfusion was shown to attenuate dynamic cerebral autoregulation (CA) yet failed to alter reaction time, thereby questioning its functional significance. No further changes were observed during hypoxia, suggesting that impaired dynamic CA occurs independently of altered systemic O2 availability. However, impaired dynamic CA may reflect a technical artifact, given the confounding influence of additional inputs that could potentially distort the mean arterial pressure-mean middle cerebral artery blood velocity relationship.
KW - Cerebral blood flow regulation
KW - Cognitive function
KW - Transfer function analysis
U2 - 10.1152/japplphysiol.00909.2017
DO - 10.1152/japplphysiol.00909.2017
M3 - Article
C2 - 29420157
AN - SCOPUS:85052018542
VL - 124
SP - 1413
EP - 1419
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
SN - 0161-7567
IS - 6
ER -