Functional projection of cognitive functions through the human corpus callosum

Reconciling the anatomical observation that the human brain comprises two asymmetrical halves with the phenomenal unity of the mind is a puzzle that has challenged neuroscientists since the dawn of research in the field. White-matter commissural fibres of the corpus callosum constitute a critical anatomical substrate for the functional resolution of this anatomical duality. However, the extent of the functional involvement of the callosum in different domains of cognition represents, to this day, a mostly uncharted territory. Here we present a probabilistic characterization of callosal involvement in a set of cognitive functions. In particular, we estimated structural callosal connections by means of the Disconnectome approach applied to a reference sample of healthy participants while using the macro-anatomical cortical areas contained in the Harvard-Oxford template as seeds. By multiplying structural connectivity by the involvement of each cortical area in a set of cognitive functions (as derived from Neurosynth meta-analyses), we produced a voxel-wise characterization of the corpus callosum in different functional domains. We were able to highlight greater involvement of posterior callosal regions in vision and episodic memory, greater involvement of more anterior callosal regions in decision making and working memory, with somatosensory and motor functions more related to the central dorsal portion of the callosum.