"Auditory perception - Oscillations and neural coding"
Human electrical imaging studies have shown that slow oscillatory (theta-band) activity in auditory cortex entrains to the rhythmic structure of naturalistic sounds such as speech or animal vocalizations. Assuming that slow oscillations reflect changes in the excitation-inhibition balance of local networks this suggests that as a consequence of entrainment and spike-phase locking cortical neurons should sample the environment in a rhythmic fashion. We study this hypothesis using combined behavioral and electric functional imaging studies and direct recordings of single neurons in animal models. Our recent results show that humans perceptual ability to detect brief sound items depends crucially on the phase of stimulus-entrained oscillations, highlighting a permissive but not ensuring role of oscillations for perception. In addition, single neuron recordings show that the spatio-temporal receptive fields depend on the phase of slow theta band activity at which the respective spikes are elicited. This provides direct evidence for a periodic sampling of the auditory environment and bears important implications for the understanding of auditory perception.