Abstract
Integration of Sight, Hearing and Touch in Human Cerebral Cortex
by
NafiYasar
While each individual sensory modality provides us with information about a
specific aspect about our environment, our senses must be integrated for us to interact
Withtheenvironment inameaningfulway. Mythesis describes studies ofthe
interactions between Somatosensation, vision and audition using functional Magnetic
Resonance Imaging (fMRI) of normal human subjects as the primary method. In order
to study Somatosensation with fMRI we first built an MRI-CompatibIe tactile-stimulation
apparatus. This apparatus was then used for four separate studies. In the first study,
we investigated tactile responses in lateral occipital lobe, a brain region traditionally
considered "visual" cortex. We found that visual area MST, but not visual area MT,
responded to tactile stimulation. In the second study we investigated a possible
homologue to a macaque multisensory area that integrates visual, auditory and tactile
information, called the Superior Temporal Polysensory area (STP). We found responses
to tactile stimuli со-localized with auditory and visual responses in posterior superior
temporal sulcus. This is likely to be a human homologue to macaque STP. In the third
study, we used Multi Voxel Pattern Analysis (MVPA) to demonstrate that this
homologue of macaque STP (along with traditional "somatosensory" areas) can predict
the location of tactile stimulation from fMRI data. In the fourth study we used