PURPOSE:Visual stimulation increases the blood flow in the posterior cerebral artery (PCA), which supplies blood to the visual cortex by neurovascular coupling (NVC). Relative contributions of vasodilatation and pressor response on NVC during dynamic exercise are still unknown. METHODS: We measured the blood flow velocity in the PCA (PCAv) by transcranial Doppler ultrasound flowmetry during rest and exercise in 14 healthy males while they performed 12-min submaximal leg-cycle exercises at mild-, moderate-, and high-intensity, which corresponded to heart rates of 120, 140, and 160 bpm, respectively. NVC was estimated as the relative change in PCAv from 20 s eye-closing to the peak response during 40 s looking at a reversed checkerboard. Conductance index was calculated for evaluating vasodilatation as pressure divided by blood flow. RESULTS: In response to visual stimulation, a magnitude of vasodilatation was significantly decreased under the moderate-intensity, while pressor response was significantly suppressed under the high-intensity exercises, compared with the control condition. Conversely, peak response to visual stimulation in PCAv was not affected by exercise intensity though relative and absolute responses were significantly lower in the moderate- and high-intensity exercises than the control. CONCLUSION: It is suggested that the contributions of pressor response and vasodilatation were modified by exercise intensity, partly playing a role for stabilizing the peak response of PCAv with visual stimulation during dynamic exercise.
RCT Entities:
PURPOSE: Visual stimulation increases the blood flow in the posterior cerebral artery (PCA), which supplies blood to the visual cortex by neurovascular coupling (NVC). Relative contributions of vasodilatation and pressor response on NVC during dynamic exercise are still unknown. METHODS: We measured the blood flow velocity in the PCA (PCAv) by transcranial Doppler ultrasound flowmetry during rest and exercise in 14 healthy males while they performed 12-min submaximal leg-cycle exercises at mild-, moderate-, and high-intensity, which corresponded to heart rates of 120, 140, and 160 bpm, respectively. NVC was estimated as the relative change in PCAv from 20 s eye-closing to the peak response during 40 s looking at a reversed checkerboard. Conductance index was calculated for evaluating vasodilatation as pressure divided by blood flow. RESULTS: In response to visual stimulation, a magnitude of vasodilatation was significantly decreased under the moderate-intensity, while pressor response was significantly suppressed under the high-intensity exercises, compared with the control condition. Conversely, peak response to visual stimulation in PCAv was not affected by exercise intensity though relative and absolute responses were significantly lower in the moderate- and high-intensity exercises than the control. CONCLUSION: It is suggested that the contributions of pressor response and vasodilatation were modified by exercise intensity, partly playing a role for stabilizing the peak response of PCAv with visual stimulation during dynamic exercise.
Authors: C K Willie; F L Colino; D M Bailey; Y C Tzeng; G Binsted; L W Jones; M J Haykowsky; J Bellapart; S Ogoh; K J Smith; J D Smirl; T A Day; S J Lucas; L K Eller; P N Ainslie Journal: J Neurosci Methods Date: 2011-01-27 Impact factor: 2.390
Authors: C K Willie; E C Cowan; P N Ainslie; C E Taylor; K J Smith; P Y W Sin; Y C Tzeng Journal: J Neurosci Methods Date: 2011-04-01 Impact factor: 2.390
Authors: Anthony R Bain; Kurt J Smith; Nia C Lewis; Glen E Foster; Kevin W Wildfong; Christopher K Willie; Geoffrey L Hartley; Stephen S Cheung; Philip N Ainslie Journal: J Appl Physiol (1985) Date: 2013-07-03
Authors: K J Smith; L E Wong; N D Eves; G J Koelwyn; J D Smirl; C K Willie; P N Ainslie Journal: Respir Physiol Neurobiol Date: 2012-08-16 Impact factor: 1.931
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