Functional MRI of human auditory cortex using block and event-related designs

fMRI of human auditory cortex response to sinusoidal tones of 200, 1000, an d 3000 Hz was evaluated using block design and conventional and "silent" ev ent-related designs. Conventional event-related fMRI revealed the timecours e of the BOLD response (similar to5 sec to peak, similar to4 sec full-width -half-max, and similar to 14 sec recovery to baseline). Both event-related, but not block, designs provided evidence for tonotopic organization in aud itory cortex. Sources of low-frequency activation were more lateral and ant erior than the sources of high-frequency activation (P less than or equal t o 0.05). In the block designs, repeated rapid stimulus presentation and the co-incidence of scanner noise preclude definition of tonotopic organizatio n revealed in event-related approaches. Magn Reson Med 45:254-260, 2001. (C ) 2001 Wiley-Liss, Inc.