Cortical projection topography of the human splenium: hemispheric asymmetry and individual differences.
The corpus callosum is the largest white matter pathway in the human brain. The most posterior portion, known as the splenium, is critical for interhemispheric communication between visual areas. The current study employed diffusion tensor imaging to delineate the complete cortical projection topography of the human splenium. Homotopic and heterotopic connections were revealed between the splenium and the posterior visual areas, including the occipital and the posterior parietal cortices. In nearly one third of participants, there were homotopic connections between the primary visual cortices, suggesting interindividual differences in splenial connectivity. There were also more instances of connections with the right hemisphere, indicating a hemispheric asymmetry in interhemispheric connectivity within the splenium. Combined, these findings demonstrate unique aspects of human interhemispheric connectivity and provide anatomical bases for hemispheric asymmetries in visual processing and a long-described hemispheric asymmetry in speed of interhemispheric communication for visual information.
Putnam
Mary Colvin
MC
Harvard Medical School, USA.
Steven
Megan S
MS
Doron
Karl W
KW
Riggall
Adam C
AC
Gazzaniga
Michael S
MS
D000328:Adult; D000344:Afferent Pathways / Q000502:physiology; D000704:Analysis of Variance; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D003337:Corpus Callosum / Q000502:physiology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007206:Individuality; D008297:Male; D012727:Sex Characteristics; D055815:Young Adult