Objective: 

We tested the scope for describing the topography of human corpus callosum (CC) with functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI).

Methods:We reviewed our recent published and unpublished fMRI data on the cortical representation of tactile, gustatory and visual sensitivity and motor activation obtained in 36 healthy volunteers and three partially callosotomized patients, two with anterior and one with posterior callosal resection. Anatomical correlates of functional activation were obtained from DTI and diffusion tensor tractography (DTT) data from 16 healthy subjects and the three patients.

Results: 

In intact subjects taste stimuli activated anterior CC, motor tasks central CC, tactile stimuli central and posterior CC, and visual stimuli the splenium. DTT reconstruction of callosal fibers connecting activated gustatory, motor, somatosensory and visual cortices showed bundles crossing respectively through genu, anterior and posterior body, and splenium at sites harboring fMRI foci. In the patient with anterior callosotomy sparing only splenium a BOLD focus was observed after visual stimulation. In the one with anterior callosotomy also sparing posterior callosal body a focus was induced by tactile stimulation. In the patient with posterior callosotomy sparing only genu an activation focus was elicited by gustatory stimulation. In all patients, fibers connecting cortical areas activated by peripheral stimulation crossed the CC through sites harboring corresponding BOLD foci.

Conclusions: 

The functional topography of the CC described in present study agrees with previous reports.