The size of the anterior corpus callosum correlates with the strength of hemispheric encoding-retrieval asymmetry in the ventrolateral prefrontal cortex

Functional lateralization of episodic memory processes in the frontal lobe is an area of intense study in the field of cognitive neuroimaging. Yet, to date there is insufficient knowledge of what role the interhemispheric structural connectivity plays in this lateralized organization. We analyzed functional and structural magnetic resonance imaging data from healthy adult volunteers who performed an associative encoding and retrieval task. We examined the relationship between functional voxel-based relative asymmetry of encoding and retrieval in the frontal lobes and the size of the anterior corpus callosum (antCC; corrected for brain size). The size of the antCC was strongly associated to the relative encoding-retrieval asymmetry in the ventrolateral prefrontal cortex (BA 47). These findings show that the functional asymmetry of episodic memory processes in the frontal lobes is associated with the structural connectivity between the hemispheres.

► Functional lateralization of memory processes depends on corpus callosum size.
► Anterior corpus callosum size is associated with recruitment of ventrolateral PFC.
► Dorsolateral PFC asymmetry in episodic memory not associated to corpus callosum.