- 作者：M. Parazzini ; E. Rossi ; R. Ferrucci ; P. Ravazzani ; A. Priori
- 刊名：Clinical Neurophysiology
- 出版年：2013
- 出版时间：October, 2013
- 年：2013
- 卷：124
- 期：10
- 页码：e172-e173
- 全文大小：236 K
lass=""h4"">Introduction
Transcranial direct current stimulation over the cerebellum (or cerebellar tDCS) modulates motor and cognitive brain circuits (). There are however still open questions on cerebellar tDCS. One of these is the amount and the spatial distribution of the electrical current that crosses the skull and reaches the cerebellum.lass=""h4"">Objective
To evaluate the electric field (lass=""boldFont"">E) and the current density (lass=""boldFont"">J) generated by cerebellar transcranial DC stimulation in different brain structures using electromagnetics computational techniques applied to a realistic human model.
lass=""h4"">Materials and methods
The computation was conducted using the simulation platform SEMCAD X (Schmid & Partner Engineering AG, Zurich, Switzerland) solving the Laplace equation. One realistic human model of the Virtual Family () was used. The model is based on high resolution magnetic resonance images of an healthy volunteer (a 26-years-old female adult model ¡°Ella¡±). The model consists of up to 77 different tissues, the dielectric properties of which were assigned on the basis of the data at low frequency . The active electrode was placed on the scalp over the cerebellum and the reference over the right arm. The electrodes were modeled as sponge material, consisting of a rectangular pad conductors placed within a sponge. The stimulating current was 2 mA. To assess how much the results depend on the exact electrode placement, the active electrode was moved longitudinally and laterally of ¡À0.5 cm.
lass=""h4"">Results
The peak values of lass=""boldFont"">E and lass=""boldFont"">J in the cerebellum are higher than the ones in the cortex of 56 % and of 73 % respectively. The percentage of volume of the cortex where the amplitude of lass=""boldFont"">E is greater than 70 % of the peak found in the cerebellum it is much less than 1 % . Varying the position of the active electrode of ¡À0.5 cm longitudinally and laterally, the maximum variation of the peak values of lass=""boldFont"">E and lass=""boldFont"">J in the cortex and in the cerebellum is of 4 % .
lass=""h4"">Conclusion
The higher amplitudes of the electric field (and/or the current density) occur mainly in the cerebellum with a spread toward the occipital region of the cortex. Data, moreover, show that small changes in the positioning of the active electrode result in a small effect on the induced field amplitudes in all the brain structures here analyzed. The model shows that the cerebellum is the main structure involved by cerebellar transcranial DC stimulation in humans and the current spread to other structures is negligible, probably without any physiological relevance.