Recruitment of the middle temporal area by tactile motion in congenital blindness.

We used positron emission tomography to investigate whether tactile motion discrimination activates the dorsal visual stream in congenitally blind (CB) participants compared with sighted controls. The tactile stimuli consisted of either static dots, dots moving coherently in one of two possible directions, or in random directions. Although CB and sighted controls performed equally well on the motion discrimination task, only CB showed increased activation in the right middle temporal area. In addition, CB also activated other visual areas including the cuneus and extrastriate area V3. These results indicate that the dorsal visual pathway is activated by tactile motion stimuli in CB, therefore providing additional support for the cross-modal plasticity hypothesis.