The principle of Magnetoencephalography (MEG) is based on detecting and recording the tiny magnetic fields produced by electrical currents within the brain's neurons.
Here's a breakdown of the principle:
-
Neuronal Activity and Electrical Currents: Brain cells (neurons) communicate with each other through electrical signals. This communication involves the flow of ions (charged particles) across neuronal membranes, creating electrical currents.
-
Magnetic Field Generation: According to the laws of electromagnetism, any electrical current generates a corresponding magnetic field. The small electrical currents within the brain's neurons, therefore, produce extremely weak magnetic fields.
-
Detection by SQUIDs: MEG uses highly sensitive magnetic sensors called Superconducting Quantum Interference Devices (SQUIDs) to detect these minute magnetic fields. SQUIDs are incredibly sensitive and require extremely low temperatures (near absolute zero) to function properly.
-
Mapping Brain Activity: By measuring the strength and location of the magnetic fields at various points around the head, MEG can create a map of brain activity in real-time. This map reflects the underlying electrical activity of the neurons and provides insights into brain function.
-
Non-Invasive Nature: MEG is a non-invasive technique, meaning it doesn't require any surgical procedures or the introduction of foreign substances into the body. This makes it a safe and well-tolerated method for studying brain activity in both healthy individuals and patients with neurological disorders.
In essence, MEG works by "listening" to the brain's magnetic whispers caused by neuronal electrical activity, allowing researchers and clinicians to understand and diagnose various brain conditions.
