Realistic simulations of neuronal activity: a contribution to the debate on direct detection of neuronal currents by MRI.
Neuroimage
; 39(1): 87-106, 2008 Jan 01.
Article
en En
| MEDLINE
| ID: mdl-17936018
ABSTRACT
Many efforts have been done in order to preview the properties of the magnetic resonance (MR) signals produced by the neuronal currents using simulations. In this paper, starting with a detailed calculation of the magnetic field produced by the neuronal currents propagating over single hippocampal CA1 pyramidal neurons placed inside a cubic MR voxel of length 1.2 mm, we proceeded on the estimation of the phase and magnitude MR signals. We then extended the results to layers of parallel and synchronous similar neurons and to ensembles of layers, considering different echo times, voxel volumes and neuronal densities. The descriptions of the neurons and of their electrical activity took into account the real neuronal morphologies and the physiology of the neuronal events. Our results concern (a) the expected time course of the MR signals produced by the neuronal currents in the brain, based on physiological and anatomical properties; (b) the different contributions of post-synaptic potentials and of action potentials to the MR signals; (c) the estimation of the equivalent current dipole and the influence of its orientation with respect to the external magnetic field on the observable MR signal variations; (d) the size of the estimated neuronal current induced phase and magnitude MR signal changes with respect to the echo time, voxel-size and neuronal density. The inclusion of realistic neuronal properties into the simulation introduces new information that can be helpful for the design of MR sequences for the direct detection of neuronal current effects and the testing of bio-electromagnetic models.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Mapeo Encefálico
/
Potenciales de Acción
/
Imagen por Resonancia Magnética
/
Interpretación de Imagen Asistida por Computador
/
Potenciales de la Membrana
/
Modelos Neurológicos
/
Neuronas
Tipo de estudio:
Diagnostic_studies
Límite:
Humans
Idioma:
En
Revista:
Neuroimage
Asunto de la revista:
DIAGNOSTICO POR IMAGEM
Año:
2008
Tipo del documento:
Article
País de afiliación:
Italia
Pais de publicación:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA