Representative subject result. (A) Individual auditory-evoked magnetic fields under each condition. N1m responses are indicated by the red vertical lines. (B) Isocontour maps of the magnetic fields at the N1m latency. The magnetic contour maps show clear dipolar patterns above the left auditory cortex. Red and blue contour lines represent the outbound and inbound flows of magnetic fields from and into the brain. Different scales were used between the silent and noisy conditions. (C) Source estimation. Estimated equivalent current dipoles at the latency of the maximal N1m response are illustrated together with a three-dimensional head and brain model reconstructed from the individual MRI. The spheres and barrels indicate the locations and orientations of the single dipoles in the left (red) and right (blue) hemispheres.