Evidence for reactive magnetic 10-Hz rhythm in the human auditory cortex

We tested the hypothesis that neurons in the human auditory cortex show spontaneous oscillations around 10 Hz, and that this activity ('tau' rhythm) is affected by auditory input. Cortical activity was recorded with a 122-channel whole-scalp neuromagnetometer from healthy adults while they were presented with monaural 500-ms bursts of white noise. The reactivity of spontaneous oscillations was studied over the whole cortex using the Temporal Spectral Evolution method. Oscillatory 6.5-9.5 Hz activity, with sources in the superior temporal lobes, was transiently suppressed by the sounds in eight out of nine subjects. Our results support the existence of a distinct, reactive auditory rhythm in the human temporal cortex.