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Contribution of arterial blood pressure and PaCO2 to the cerebrovascular responses to motor stimulation.
MedLine Citation:
PMID:  22058160     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Motor stimulaton induces a neurovascular response that can be detected by continuous measurement of cerebral blood flow (CBF). Simultaneous changes in arterial blood pressure (ABP) and PaCO(2) have been reported but their influence on the CBF response has not been quantified. Continuous bilateral recordings of CBF velocity (CBFV), ABP and end-tidal CO(2) (EtCO(2)) were obtained in 10 healthy middle-aged subjects at rest and during 60 s of repetitive, metronome controlled (1Hz) elbow flexion. A multivariate autoregressive-moving average (ARMA) model was adopted to quantify the relationship between beat-to-beat changes in ABP, breath-by-breath EtCO2 and the motor stimulus, represented by the metronome on-off signal (inputs), and the CBFV response to stimulation (output). All three inputs contributed to explain CBFV variance following stimulation . For the ipsi- and contralateral hemispheres, ABP explained 20.3 ± 17.3% (p=0.0007) and 19.5 ± 17.2% (p=0.01) of CBFV variance, respectively. Corresponding values for EtCO2 and metronome signals were 22.0 ± 24.2% (p=0.008), 24.0 ± 24.1% (p=0.037) and 32.7 ± 22.5% (p=0.0015), 43.2 ± 25.1% (p=0.013), respectively. Synchronized population averages suggest that the inital sudden change in CBFV was largely due to ABP, while the influence of EtCO(2) was more erratic. The component due to elbow flexion showed a well defined pattern, with rise time slower than the main CBFV change, but reaching a stable plateau after 15 s of stimulation. Identifying and removing the influences of ABP and PaCO(2) to motor-induced changes in CBF should lead to more robust estimates of neurovascular coupling and better understanding of its physiological co-variates.
Authors:
Ronney B Panerai; Angela S M Salinet; Thompson G Robinson
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-11-4
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  -     ISSN:  1522-1539     ISO Abbreviation:  -     Publication Date:  2011 Nov 
Date Detail:
Created Date:  2011-11-7     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
1University of Leicester.
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