Previous neuroimaging studies identified a large network of cortical areas
involved in visual imagery in the human brain, which includes occipitotempo
ral and visual associative areas. Here we test whether the same processes c
an be elicited by tactile and auditory experiences in subjects who became b
lind early in life. Using positron emission tomography, regional cerebral b
lood flow was assessed in six right-handed early blind and six age-matched
control volunteers during three conditions: resting state, passive listenin
g to noise sounds, and mental imagery task (imagery of object shape) trigge
red by the sound of familiar objects. Activation foci were found in occipit
otemporal and visual association areas, particularly in the left fusiform g
yrus (Brodmann areas 19-37), during mental imagery of shape by both groups.
Since shape imagery by early blind subjects does involve similar visual st
ructures as controls at an adult age, it indicates their developmental cros
smodal reorganization to allow perceptual representation in the absence of
vision. (C) 2001 Academic Press.