Both MEG and EEG systems are used to monitor the brain activity but still, there are some differences between these two sensing devices. MEG is a functional neuroimaging technique used for mapping brain activity by recording magnetic field produced naturally in the brain. Whereas EEG is an electrophysiological monitoring method used to measure the activity of the brain by recording the electrical fields. If you also want to purchase MEG/EEG sensors you can ask the local distributor, who provides remarkable magnetic sensing devices, MEG/EEG consulting and magnetic field site surveys.
Let’s discuss in detail about MEG systems and how is it different from the EEG and MRI:
What is an MEG System?
Magnetoencephalography (MEG) is a non-invasive sensor used for investigating the human brain activity. It is capable of measuring ongoing brain activity on a millisecond-by-milliseconds basis and for this very sensitive magnetometers are used.
How Does MEG Scanner Works?
At the cellular level, individual neurons in the brain have electrochemical characteristics that cause the flow of electrically charged ions through a cell. As the neuromagnetic signals that are produced by the net effect of the slow ionic current flow are very small. For effective working MEG sensors require (SQUID) superconducting quantum interference device is kepy in a big liquid helium cooling unit which is set at approximately -269 degrees C. This is necessary to do as it helps SQUID devices in detecting and amplifying magnetic fields generated by neurons effectively.
Advantages of MEG Over EEG and fMRI Systems:
MEG has more benefits than fMRI and EEG. As MEG provides timing as well as spatial information about brain activity. fMRI(Functional Magnetic Resonance Imaging or functional MRI )measures the oxygenation of the blood flowing near the active neurons and the activity of the brain is reflected indirectly by fMRI signals. While MEG signals are obtained directly from neuronal electrical activity and are able to show absolute neuronal activity.
The main advantage of MEG system is that signal produced can be recorded in sleeping subjects; however, this is not the case with the fMRI system. With fMRI there is no involvement of head movements during recording, while in MEG measurement one can move their heads within the MEG helmet.
Moreover, MEG sensors provide more accurate spatial localization of neural activities than EEG, a complementary method of recording brain activity. So all MEG/EEG consulting companies prefer to choose these devices rather than other sensing instruments.
Most importantly, MEG provides a right temporal information about the brain activation with sub-millisecond precision. Whereas fMRI and EEG measurement provide a poor temporal information.
Difference between MEG and EEG Systems:
MEG and EEG are closely related but you will still find some differences, which are as follow -
EEG detects the electric signals generated by the neural currents instead of the corresponding magnetic fields.
Most important difference is that the skull and the tissue around the brain gets affected with the magnetic fields when monitored by MEG which is much less than they get affected with the electrical impulses measured by EEG scanners.
MEG results in better spatial resolution, as magnetic fields are less distorted by tissues of different conductivity as compared to the electric potential measured with electroencephalography (EEG).
Data interpretation is easier in MEG and it detects only tangential current. Whereas EEG detects both radial and tangential currents.
MEG primarily detects intracellular currents whereas EEG is sensitive to extracellular volume currents.
You have the complete information about the MEG and EEG systems, so whenever you visit a MEG/EEG consulting companies for buying sensing devices you can judge the difference and can choose a right device according to your need.
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