Supervisor: Sarang Dalal

The human brain is a complex structure consisting of at least 1010 neurons in the cerebral cortex. While processing information when many neurons become active simultaneously, it generates electric currents that induce weak magnetic fields of 50-500 fT. We explore the measurement techniques of these magnetic fields through a process known as magnetoencephalography (MEG). In the process, these extremely low magnetic fields can only be measured non-invasively by a Superconducting Quantum Interference Device (SQUID) and Optically Pumped Magnetometer (OPM). On one hand, SQUID works on the principle of a superconducting ring consisting of Josephson junctions which allow the measurement of very weak magnetic field, whereas OPMs use atomic vapour cells to achieve high sensitivity. Interestingly, these measurements of the neural signals are found significant in clinical treatments such as epilepsy. For instance, OPM-MEG systems deployed at Aarhus University Hospital (AUH) use the MEG technology to study brain function.