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Neural Plasticity
Volume 2013 (2013), Article ID 251308, 15 pages
http://dx.doi.org/10.1155/2013/251308
Research Article

Functional Topography of Human Corpus Callosum: An fMRI Mapping Study

1Sezione di Neuroscienze e Biologia Cellulare, Dipartimento di Medicina Sperimentale e Clinica, Università Politecnica delle Marche, 60020 Ancona, Italy
2Sezione di Scienze Radiologiche, Dipartimento di Scienze Cliniche Specialistiche e Odontostomatologiche, Università Politecnica delle Marche, 60020 Ancona, Italy

Received 7 September 2012; Revised 26 November 2012; Accepted 4 December 2012

Academic Editor: Giorgio M. Innocenti

Copyright © 2013 Mara Fabri and Gabriele Polonara. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The concept of a topographical map of the corpus callosum (CC) has emerged from human lesion studies and from electrophysiological and anatomical tracing investigations in other mammals. Over the last few years a rising number of researchers have been reporting functional magnetic resonance imaging (fMRI) activation in white matter, particularly the CC. In this study the scope for describing CC topography with fMRI was explored by evoking activation through simple sensory stimulation and motor tasks. We reviewed our published and unpublished fMRI and diffusion tensor imaging data on the cortical representation of tactile, gustatory, auditory, and visual sensitivity and of motor activation, obtained in 36 normal volunteers and in 6 patients with partial callosotomy. Activation foci were consistently detected in discrete CC regions: anterior (taste stimuli), central (motor tasks), central and posterior (tactile stimuli), and splenium (auditory and visual stimuli). Reconstruction of callosal fibers connecting activated primary gustatory, motor, somatosensory, auditory, and visual cortices by diffusion tensor tracking showed bundles crossing, respectively, through the genu, anterior and posterior body, and splenium, at sites harboring fMRI foci. These data confirm that the CC commissure has a topographical organization and demonstrate that its functional topography can be explored with fMRI.