Practice makes perfect: The neural substrates of tactile discrimination by Mah-Jong experts include the primary visual cortex

Abstract

Background: It has yet to be determined whether visual-tactile cross-modal plasticity due to visual deprivation, particularly in the primary visual cortex (VI), is solely due to visual deprivation or if it is a result of long-term tactile training. Here we conducted an fMRI study with normally-sighted participants who had undergone long-term training on the tactile shape discrimination of the two dimensional (2D) shapes on Mah-Jong tiles (Mah-Jong experts). Eight Mah-Jong experts and twelve healthy volunteers who were naïve to Mah-Jong performed a tactile shape matching task using Mah-Jong tiles with no visual input. Furthermore, seven out of eight experts performed a tactile shape matching task with unfamiliar 2D Braille characters. Results: When participants performed tactile discrimination of Mah-Jong tiles, the left lateral occipital cortex (LO) and VI were activated in the well-trained subjects. In the naïve subjects, the LO was activated but VI was not activated. Both the LO and VI of the well-trained subjects were activated during Braille tactile discrimination tasks. Conclusion: The activation of VI in subjects trained in tactile discrimination may represent altered cross-modal responses as a result of long-term training. © 2006 Saito et al; licensee BioMed Central Ltd.