Functional Topography of Human Corpus Callosum: An fMRI Mapping Study
Activation evoked by visual stimulation in callosotomy patients. (a) CVF stimulation in patient D.B. Cortical activation is seen in the occipital cortex of both hemispheres ((a)1) and in the splenium ((a)2, green arrow). Fibers arising from the activated cortex ((a)1, green circle) cross the CC through the extant part of the splenium ((a)3, yellow arrow). (b) and (c) Activation evoked by peripheral visual stimulation in patients O.T. (b) and P.F. (c). Cortical activation is seen in the occipital cortex of the contralateral hemisphere ((b)1 and (c)1) and in the splenium ((b)2 and (c)1 and 2, green arrows). Fibers arising from the activated cortex ((b)1 and (c)1, green circles) cross the CC through the spared portion of the splenium ((b)3 and (c)3, yellow arrows). Note that in VI the fiber bundle arising from the representation of the peripheral retina and crossing the splenium is much thinner than the bundle arising from the foveal representation, pictured in (a). On DTI images, a thin white line demarcates the CC. Numbers on each brain represent the Talairach coordinates (, , ) of each focus (green arrows). Left hemisphere on the right.