Researchers at Aalto University in Finland have developed the world’s most accurate device for mapping brain activity. Thanks to new low-field MRI, the device is the first to successfully combine the previously incompatible MRI and MEG (whole-head magnetoencephalography) technology. At only a few hundred-thousandths of the strength of magnetic fields used in traditional high-field MRI, the fields in new low-field MRI do not interfere with the fields used in MEG. The marriage of these two technologies allows the MEG-MRI device to attain what the researchers describe as “unprecedented accuracy” when mapping activity in the human brain. The devices was specifically designed to provide better mapping of patients with epilepsy. However, as a happy consequence of the MEG-MRI combination, the device can also aid in more accurately identifying tumors due to increased image contrast, and allow for imaging in previously excluded patients with metal implants.