The name is absent

48

delivered at a fixed intensity (10 dB attenuation equivalent to 30 V driving voltage and
approximately 153 μm displacement for four subjects; 15 dB attenuation, 17V, 72 μm
for three subjects; 17 dB, 13V, 72 μm for five subjects). To set the level of the strong
auditory stimulus, an auditory stimulus was presented at the same time as the strong
tactile stimulus. Subjects used the MR-CompatibIe response buttons to adjust the
intensity of the auditory stimulus until it matched the perceived magnitude of the
strong tactile stimulus (mean attenuation 16 dB±2 dBSEM, mean sound pressure level
72 dB+2 dB). To set the level of the weak tactile stimulus, subjects decreased the
intensity of the strong tactile stimulus until it was very weak but could still be detected
on every presentation (50±l dB attenuation, 0.3V±0.04V, 1.6±0.2 μm displacement).
This threshold was consistent with previous psychophysical studies using 200 Hz
Vibrotactile stimulation (Brisben, et al. 1999). To set the level of the weak auditory
stimulus, subjects adjusted the intensity of the auditory Stimulusto match the intensity
of a simultaneously presented weak tactile stimulus (42 dB±2 dB attenuation, 49+2 dB
SPL).

Visuallocalizer

To identify visually-responsive brain regions, a block-design visual Iocalizer was
conducted, in which subjects performed no task but alternately viewed 30-second
excerpts from a movie (Winged Migration, Sony Pictures Classics) and fixation baseline.

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