Posterior Corpus Callosum and Interhemispheric Transfer of Somatosensory Information: An fMRI and Neuropsychological Study of a Partially Callosotomized Patient

Abstract

Interhemispheric somatosensory transfer was studied by functional magnetic resonance imaging (fMRI) and neuropsychological tests in a patient who underwent resection of the corpus callosum (CC) for drug-resistant epilepsy in two stages. The first resection involved the anterior half of the body of CC and the second, its posterior half and the splenium. For the fMRI study, the hand was stimulated with a rough sponge. The neuropsychological tests included: Tactile Naming Test (TNT), Same-Different Recognition Test (SDRT), and Tactile Finger Localization Test (intra- and intermanual tasks, TFLT). The patient was studied 1 week before and then 6 months and 1 year after the second surgery. Before this operation, unilateral tactile stimulation of either hand activated contralaterally the first (SI) and second (SII) somatosensory areas and the posterior parietal (PP) cortex, and SII and PP cortex ipsilaterally. All three tests were performed without errors. In both postoperative sessions, somatosensory activation was observed in contralateral SI, SII, and PP cortex, but not in ipsilateral SII and PP cortex. Performance was 100% correct in the TNT for the right hand, but below chance for the left; in the other tests, it was below chance except for TFLT in the intramanual task. This case provides the direct demonstration that activation of SII and PP cortex to stimulation of the ipsilateral hand and normal interhemispheric transfer of tactile information require the integrity of the posterior body of the CC.

Upper Limb Asymmetries in the Matching of Proprioceptive Versus Visual Targets

“…Given that this task is dependent on the interhemispheric transfer of memorized proprioceptive feedback prior to making an accurate matching movement (Fabri et al 2001;Sperry et al 1969), one may logically conclude that subjects more readily transferred this information from the left to the right hemi- sphere. This directional bias with respect to the interhemispheric transfer of memorized positional information has previously been reported in studies assessing the transfer of learning following opposite-arm training in a visuomotor rotation task.…”

Dynamic network structure of interhemispheric coordination

“…The anatomical locations of these regions might depend on the type of information being processed. Indeed, evidence from partial split-brain patients suggests that callosal transfer of somatosensory information occurs between regions of posterior cortex (34)(35)(36), whereas the transfer of other higher level cognitive information might occur between more anterior regions of temporal and frontal cortex (37).…”

Intermanual Transfer of Shapes in Preterm Human Infants From 33 to 34 + 6 Weeks Postconceptional Age

“…Regardless, these results provided evidence of intermanual transfer of shape in full-term newborns with the hypothesis that the development of the corpus callosum would be sufficient to permit some transfer of shape information between the two hands. Indeed, an fMRI study demonstrated the essential contribution of posterior corpus callosum to the interhemispheric transfer of tactile information (Fabri et al, 2001(Fabri et al, , 2005. Considering that the corpus callosum is less mature in preterm infants than full-term infants (Anderson, Laurent, Woodward, & Inder, 2006) and that very preterm birth (before 33 GW) might be associated with perinatal brain injury including the corpus callosum (Kontis et al, 2009), we wanted to determine if preterm infants are capable of intermanual transfer of shape after the age of 33 GW.…”