Visualization of auditory habituation by fMRI.

The aim of this study was to measure and quantify habituation phenomena within the auditory cortex of 18 healthy subjects by means of fMRI. Auditory stimulation was done by digitally generated pulsed (nu = 5 Hz) 800-Hz sine tones with three alternating ON (duration 2 min) and OFF (1 min) periods. Binaural stimulation resulted in symmetrical bihemispheric activation of the auditory cortex. Our data revealed a characteristic signal decay to repeated acoustic stimulation: the response to the second was even more pronounced, and the third stimulation block significantly lower compared to the first. Thus, our data clearly demonstrate habituation phenomena, probably due to reduced neuronal activity with increased duration and/or frequency of stimuli.