Every nerve cell in our body produces a tiny magnetic field when it fires. If we had magnetic sensors sensitive enough to measure such faint signals – 10 million times weaker than the Earth’s magnetic field – we could non-invasively study the activity of neurons inside our bodies and gain a deeper understanding of how they work together in networks. This could ultimately let us screen for and prevent neurodegenerative diseases or provide remote control signals for prosthetic limbs. In BIO-MAG we will develop two different and complementary magnetic sensing technologies that work at room-temperature based on new 2D materials: microscale extraordinary magnetoresistive (EMR) devices and nano-scale magneto-optical color centers. By combining these technologies in arrays of ultrasensitive magnetic field sensors we will gain unprecedented insight into neurons, neural networks, and the workings of the human mind.