A highlight, especially for the team of the projects B2 and B6 of the CRC 1261, was the magnetic measurement of nerve signals with a 304 SQUID vector magnetometer at the PTB in Berlin. For further development and also for optimization of our uncooled magnetoelectric (ME) sensors, a better understanding of spectral power distribution and signal strength of nerve signals is of particular interest. Since the magnetic field of human nerve pulses is quite low, only signal amplitudes in the fT range from the deep nerve are measurable. The project B6 intensively prepared these measurements, since an earlier attempt at measuring the signals had completely failed. Finally, Christin Bald and Eric Elzenheimer succeeded in measuring nerve signals magnetically, which also fits to the current electrical gold standard (electroneurography). Signal amplitudes were subject dependent and ranged from 17 fT to 60 fT in a frequency range from 100 Hz to 1 kHz. The required averaging time was in the range of minutes, while for current ME sensors significantly longer averaging times are expected to be necessary.
