Kinetic Modeling of the Blood Oxygenation Level Dependent (BOLD) Signals and Biocatalytic Reactions Observed in the Human Brain Using MRI: An Analysis of Normal and Pathological Conditions

Abstract

A kinetic model describing the pulse of increased oxygen concentrations and the subsequent changes in the concentration of Nacetylaspartate in the excited nervous tissue of the human brain in response to an external signal is presented. The model is based on biochemical data, a multistage and nonlinear dynamic process the BOLD signal and Nacetylaspartate. The existence of multiple steady states explains the triggering effect of the system. The inhibitory effect of the substrate is a necessary factor for the autostabilization of N-acetylaspartate. The kinetic model allows the dynamic behavior of previously unmeasurable metabolites, namely, products of the hydrolysis of N-acetylaspartate, such as acetic and aspartic acid, and glutamic acid to be predicted. Kinetic modeling of the BOLD signal and the subsequent hydrolysis of N-acetylaspartate provides information about the biochemical and dynamic characteristics of some pathological conditions (schizophrenia, Canavan disease, and the superexcitation of the neural network).

Neuroengineering: ferromagnetic nano (micro) implants. Magnetic-hypnotic effect control of animal behavior by an external magnetic field

“…Kinetic model of the magnetic-hypnotic effect. The kinetic model of the magnetic-hypnotic effect is based on kinetic ideas of neuronal-synaptic structures functioning that we have developed [20][21][22][23][24][25][26][27]. The basic provisions are as follows:…”

“… The main magnetically active component of the brain and blood system is deoxyhemoglobin (the number of Bohr magnetons for deoxyhemoglobin is 5, while for oxyhemoglobin it is 0). This difference is the basis for the BOLD (Blood-Oxygen-Level-Dependent) effect, which is well manifested and studied by the functional magnetic resonance imaging [23][24][25][26][27].…”

Dynamics of the Multipathway Regulation of the Vasodilator Bold Effect Induced by a Nerve Impulse: A Kinetic Model of the Neurovascular Coupling Process

“…To construct a biochemical sequential-parallel scheme, the data from ref were used. A kinetic model of the changes in oxygen concentration was built on base the results from previous studies − ,, and served as the experimental data for the analysis of the dynamic changes in the BOLD signal. The ordinary differential equation (ODE) system was integrated using a specially developed program (in the Delphi Community Edition).…”

“…17−20 We were able to describe the observed dynamics of the BOLD signal and a number of subsequent metabolic processes on the basis of the chemical kinetic approach. 17 The complexity of neurovascular coupling should be emphasized. This process includes the following.…”

“…The elucidation of the molecular-dynamic nature of neurovascular coupling is of fundamental importance. A rather effective and fruitful approach is the kinetic modeling of the process, which allows the dynamics of the process and effects over time to be described on the basis of available experimental data. − We were able to describe the observed dynamics of the BOLD signal and a number of subsequent metabolic processes on the basis of the chemical kinetic approach …”