Functional MRI of human auditory cortex using block and event-related designs.
fMRI of human auditory cortex response to sinusoidal tones of 200, 1000, and 3000 Hz was evaluated using block design and conventional and "silent" event-related designs. Conventional event-related fMRI revealed the timecourse of the BOLD response (approximately 5 sec to peak, approximately 4 sec full-width-half-max, and approximately 14 sec recovery to baseline). Both event-related, but not block, designs provided evidence for tonotopic organization in auditory cortex. Sources of low-frequency activation were more lateral and anterior than the sources of high-frequency activation (P < or = 0.05). In the block designs, repeated rapid stimulus presentation and the co-incidence of scanner noise preclude definition of tonotopic organization revealed in event-related approaches. Magn Reson Med 45:254-260, 2001.
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Department of Radiology, University of California School of Medicine, San Francisco, CA 94143, USA.
Patel
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Roberts
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D000161:Acoustic Stimulation; D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D005071:Evoked Potentials / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*