Objective: To define further the brain regions involved in tactile object r
ecognition using functional MRI (fMRI) techniques. Background: The neural s
ubstrates involved in tactile object recognition (TOR) have not been elucid
ated. Studies of nonhuman primates and humans suggest that basic motor and
somatosensory mechanisms are involved at a peripheral level; however, the m
echanisms of higher order object recognition have not been determined. Meth
ods: The authors investigated 11 normal volunteers utilizing fMRI technique
s in an attempt to determine the neural pathways involved in TOR. Each indi
vidual performed a behavioral paradigm with the activated condition involvi
ng identification of objects by touch, with identification of rough/smooth
as the control. Results: Data suggest that in a majority of individuals, TO
R involves the calcarine and extrastriatal cortex, inferior parietal lobule
, inferior frontal gyrus, and superior frontal gyrus-polar region. Conclusi
ons: TOR may utilize visual systems to access an internal object representa
tion, The parietal cortices and inferior frontal regions may be involved in
a concomitant lexical strategy of naming the object being examined. Fronta
l polar activation likely serves a role in visuospatial working memory or i
n recognizing unusual representations of objects. Overall, these findings s
uggest that TOR could involve a network of cortical regions subserving soma
tosensory, motor, visual, and, at times,lexical processing. The primary fin
ding suggests that in this normal study population, the visual cortices may
be involved in the topographic spatial processing of TOR.