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Introduction
In everyday life, perceptual events often occur in multiple sensory modalities: we
may feel our cell phone vibrate, hear it ring, or see the display flash, all indicating an
incoming call. Where and how such multisensory processing occurs has intrigued
philosophers, psychologists, and neuroscientists since at least the time of Aristotle
(Aristotle 350 B.C.E). In the macaque monkey, an important multisensory region lies
along the fundus of the posterior superior temporal sulcus (STS), This region was
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originally labeled the Superiortemporal polysensory (STP) area because single units in
this area respond to visual, auditory and somatosensory stimulation (Bruce, et al. 1981).
Physiological and anatomical studies have delineated the cortical and subcortical
connections and functional properties of macaque STP, also sometimes referred to as
TPO (Padberg, et al. 2003). Identifying the human homolog of macaque STP will allow us
to generate additional hypotheses about the functional and anatomical properties of
human STS (Beauchamp 2005a).
In the banks of human posterior STS, neuroimaging studies have reported
multisensory responses to auditory and visual stimulation (Beauchamp, et al. 2004b;
Calvert 2001; Noesselt, et al. 2007; van Atteveldt, et al. 2004; Wright, et al. 2003). This
region has been termed STSms, the STS multisensory region (Beauchamp, et al. 2004a).
Guided by the macaque literature, we wanted to determine if STSms was also important
for processing somatosensory information. Previous human fMRI studies examining
responses to somatosensory, auditory and visual stimulation have found regions
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responsive to all three modalities in parietal and frontal cortex, but not in the STS