Effects of stimulus rate on the auditory cortex using fMRI with ‘sparse’ temporal sampling

The purpose of this study was to evaluate the effects of the auditory stimulus presentation rate on signal response during fMRI with a minimal effect of scanner acoustic noise. Six subjects received auditory stimulus with a pure tone (1000 Hz, 30 ms duration) at presentation rates of 0.5, 2, 5, 10 and 20 Hz. Echo planar images were obtained with a long TR of 12 s and clustered multi-slice acquisition. The number of activated pixels and percentage signal change were measured in the transverse temporal gyri, which revealed that these values at 5 Hz were significantly greater than those at 0.5 Hz and at 20 Hz.