FIG 5. SEMA3A immunoreactivity (A, 20-week-old fetus) is restricted to median and paramedian parts of the callosal radiation, where it is located in both cell bodies and the extracellular matrix in the ventral part of the corpus callosum (asterisk), and in the fornix system (arrow). The SEMA3A immunoreactivity is also located in the roof of the anterior horn of the lateral ventricle, corresponding to the frontal crossroad area C2 (dashed square in B, 20-week-old fetus). In addition, the expression of CD68 marker for microglia (C, 18-week-old fetus) is most prominent in the frontal crossroad area C2 (dark dots).