A model of brain circulation and metabolism: NIRS signal changes during physiological challenges.
We construct a model of brain circulation and energy metabolism. The model is designed to explain experimental data and predict the response of the circulation and metabolism to a variety of stimuli, in particular, changes in arterial blood pressure, CO(2) levels, O(2) levels, and functional activation. Significant model outputs are predictions about blood flow, metabolic rate, and quantities measurable noninvasively using near-infrared spectroscopy (NIRS), including cerebral blood volume and oxygenation and the redox state of the Cu(A) centre in cytochrome c oxidase. These quantities are now frequently measured in clinical settings; however the relationship between the measurements and the underlying physiological events is in general complex. We anticipate that the model will play an important role in helping to understand the NIRS signals, in particular, the cytochrome signal, which has been hard to interpret. A range of model simulations are presented, and model outputs are compared to published data obtained from both in vivo and in vitro settings. The comparisons are encouraging, showing that the model is able to reproduce observed behaviour in response to various stimuli.
Banaji
Murad
M
Department of Biological Sciences, University of Essex, Colchester, United Kingdom. m.banaji@ucl.ac.uk
Mallet
Alfred
A
Elwell
Clare E
CE
Nicholls
Peter
P
Cooper
Chris E
CE
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003576:Electron Transport Complex IV / Q000378:metabolism; D004734:Energy Metabolism / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008954:Models, Biological; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D049490:Systems Biology / Q000379:methods; D013816:Thermodynamics
D003576:Electron Transport Complex IV; D010100:Oxygen