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Feed-forward changes in carotid blood flow velocity during active standing

Kazuyoshi Kitaoka1, Hajime Miura, Mitsuo Kitamura

  • 1Department of Physiology, The University of Tokushima Graduate School, Tokushima 770-8503, Japan. kitaoka@basic.med.tokushima-u.ac.jp

Neuroscience Letters
|October 26, 2010
PubMed

Insights

Anticipatory cardiovascular regulation may occur before standing, indicated by changes in blood flow velocity and cerebral blood volume. This feed-forward mechanism, possibly triggered by central command, helps maintain brain blood flow during the transition to upright posture.

Area of Science:

  • Physiology
  • Cardiovascular Regulation
  • Neuroscience

Background:

  • Orthostatic changes transiently disrupt circulatory control.
  • Cardiovascular feedback systems activate to counteract instability during postural changes.

Purpose of the Study:

  • To investigate anticipatory cardiovascular regulation preceding active standing.
  • To determine if central command influences cardiovascular adjustments before postural transition.

Main Methods:

  • Continuous recording of common carotid artery blood flow velocity (BFV).
  • Measurement of cerebral blood volume (CBV) using oxyhemoglobin levels.
  • Comparison of BFV and CBV responses during reaction-time versus self-paced standing in healthy men.

Main Results:

  • A significant decrease in maximum BFV occurred before standing in the reaction-time condition, correlating with systolic blood pressure changes.
  • Anticipatory BFV decrease was absent during self-paced standing, with subsequent declines in BFV parameters.
  • Cerebral blood volume showed a significant increase in oxyhemoglobin before standing in the reaction-time condition.

Conclusions:

  • Evidence suggests a feed-forward cardiovascular regulatory mechanism activated by central command before standing.
  • This anticipatory regulation may play a role in maintaining cerebral perfusion during the transition to an upright posture.

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