MEG (not the shark)

Magnetoencephalography (MEG) is a way to measure the brains activity by detecting the magnetic fields that are created when neurons (brain cells) communicate with each other.

It's a fast, accurate and non-invasive test that helps scientists and doctors understand how the brain works. (the whole study takes about 1 hour and about 8 working hours to review)

This is an example of a MEG in its laying down position, it can also be moved to a sitting position

When neurons in the brain send electrical signals to each other, they create tiny electrical currents.

These currents generate magnetic fields.

MEG measures these magnetic fields to study how the brain is working.

To measure these magnetic fields, people wear a special helmet that has sensors inside it. They can either be sitting up in a chair or laying down. These sensors, called SQUIDs (not the sea animal but- Superconducting Quantum Interference Devices), are super sensitive and can detect even the smallest magnetic signals from the brain.

These sensors must remain cold during testing so they are surrounded by liquid helium( which is either refilled weekly or yearly by the technicians). The room the MEG is housed in is also special, it must be a magnetically shielded room. Due to the sensitive nature of the test any outside metal or loud noise can disrupt the study. Patients are given metal free gowns to wear and all magnetic residue is removed with a special wand. A lot of patients say the room reminds them of a spy because it's so quiet. The helmet looks a little like Darth Vader's helmet (which we used to joke about at my previous job).

pictured is a layout of what the internal sensors look like inside the MEG helmet

The MEG helmet measures the brains magnetic fields while the person is doing tasks or responding to different stimuli (example; tapping their fingers, looking at images or counting). MEG works very quickly, so it can track brain activity in real-time, down to milliseconds. The data is collected and turned into wave-like patterns (kind of like EEG) that show how different parts of the brain are working. One of the best things about MEG is that it can show where in the brain the activity is happening. By using computers (lots of computers) to analyze the magnetic fields, scientists can figure out which areas of the brain are involved in things like seeing, hearing, moving, or thinking (so when our patients ask " can you see what we are thinking?!", our answer in MEG is "yes!")

MEG is used in research to study how the brain works, and its also helpful in the clinical setting setting. Doctors use MEG to locate important brain areas before surgeries, like when someone has a brain tumor or epilepsy. This helps the surgeon avoid damaging critical parts of the brain during the operation. It is a non invasive test so its typically done before the option of SEEG.

Pictured is an example of a mock meg helmet, this is used to make sure the patients head will fit inside the actual meg. Most machines will only fit up to 65cm head circumference

In short, magnetoencephalography (MEG) is a tool that helps us understand the brains activity by measuring tiny magnetic fields created by neurons. Its fast, accurate, and non-invasive. And the helmet you wear during the test looks just like something out of Star Wars!

Fun fact I'm number 15 in the country to be registered in MEG!