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Evaluation of Cerebral Blood Flow Autoregulation in the Rat Using Laser Doppler Flowmetry

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Published on: January 19, 2020

Cerebral hydrodynamics are at a most a third order system.

Simon J Shepherd¹, Clive B Beggs

¹Medical Biophysics Laboratory, University of Bradford, Richmond Road, Bradford BD7 1DP, UK.

Medical Hypotheses

|February 5, 2011

Summary

The brain

Area of Science:

Neuroscience
Biomedical Engineering
Fluid Dynamics

Background:

The human brain utilizes a windkessel mechanism to regulate arterial pulse and ensure smooth cerebral blood flow.
Cerebrospinal fluid (CSF) dynamics are complex and not fully understood, impacting brain hydrodynamics.
Previous electrical analogue models of brain hydrodynamics have had limited success.

Purpose of the Study:

To investigate the order of the cerebral hydrodynamic system.
To determine the minimum model order required for accurately simulating brain hydrodynamics.
To advance the hypothesis that the cerebral system is at most a third-order system.

Main Methods:

Singular spectrum analysis (SSA) applied to arterial, venous, and CSF flow data.

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Evaluation of Cerebral Blood Flow Autoregulation in the Rat Using Laser Doppler Flowmetry

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Computation of singular vectors to analyze spectral eigen-system of fluid flows.

Analysis of variance explained by successive singular vectors.

Main Results:

The first singular vector explained 67% of the observed variance in cerebral fluid flows.
The first two singular vectors collectively explained 96% of the variance.
The first three singular vectors accounted for over 99.5% of the observed variance.

Conclusions:

The cerebral hydrodynamic system can be accurately modeled as a third-order system.
This finding provides a more precise framework for simulating brain hydrodynamics.
Understanding the system's order is crucial for successful hydrodynamic modeling.