Exploring Current Dipoles: ECG, EEG, MCG and MEG

[jefferiksen]

Hi all, new user here. I did a search on Google for "current dipole" during an idle moment, and discovered this forum and joined. There was an old, closed thread concerning "current dipole", started by basheersubei and including tiny-tim, sophiecentaur, and madness, which closed 3.5 years ago and left things hanging. If anyone is still interested, I have a lot of literature I can point you to about current dipoles as they are used in electrophysiology (mainly electrocardiography and electroencephalography - ECG and EEG, also matetic analogs MCG and MEG). Basically they are quite analogous geometrically to charge dipoles, but are modeled as positive and negative point current sources with a small separation, embedded in a conductive medium. In an infinite medium, lines of current flow are analogous to electric field lines in the charge dipole case, and equipotential lines are the same shape. Do a search for authors like Robert Plonsey and Jacob Malmivuo going back to the 1950s. As an aside, a current dipole also produces a magnetic field, though I am not sure at this point if the field so produced is equivalent to that from a magnetic dipole.

 

[eljose79]

Thank you for bringing up the topic of current dipoles and their applications in electrophysiology. I am always interested in learning about different phenomena and their practical uses.

I would like to add to your post by discussing the concept of a current dipole and its relationship to a magnetic dipole. As you have mentioned, a current dipole is modeled as two point current sources with opposite direction and a small separation, embedded in a conductive medium. This configuration creates a flow of current between the two sources, similar to the flow of electric charge in a charge dipole.

In terms of the magnetic field produced by a current dipole, it is indeed equivalent to that of a magnetic dipole. This is because both dipoles have a similar distribution of currents and produce a magnetic field that follows the same laws of electromagnetism. In fact, a current dipole can be thought of as a magnetic dipole with a very small magnetic moment.

The use of current dipoles in electrophysiology, specifically in ECG and EEG, is crucial in understanding the electrical activity of the heart and brain. By measuring the electric potential on the surface of the body, we can determine the location and strength of current dipoles in the heart and brain, providing valuable information about their functioning.

I would also like to mention that current dipoles have been studied extensively in the field of bioelectromagnetism, with pioneers such as Robert Plonsey and Jacob Malmivuo. Their work has greatly contributed to our understanding of current dipoles and their applications in electrophysiology.

Thank you for sharing your knowledge and literature on current dipoles. I hope this discussion has been informative and I look forward to hearing more from you and other members of this forum.