Lateral View of the Brain With a Centered Window at the Level of the Intraparietal Sulcus. A, Lateral view of the brain with a centered window at the level of the intraparietal sulcus (IPS). After the dissection of the sagittal stratum and most of the optic radiations, the vertical fibers of the tapetum are exposed. In this picture, a direct opening is made to the ventricular atrium between the tapetum fibers after the resection of the ependyma. To understand the approximate localization of the optic radiations (OR), the sagittal stratum is labeled as OR but they are only a part of the sagittal stratum, as stated in the Results section. All the labeling comes from previous knowledge. B, Panoramic lateral view of the brain identifying the dissection of the OR at the atrium level. In a deeper layer, we identify the vertical tapetum fibers and more medially, the ependyma (last layer until the access to the VA). In this picture, the anterior relationships to the thalamus and caudate nucleus are shown. C, Transillumination of the ventricular atrium, temporal, and occipital horns, showing the optic radiations, tapetum fibers, and ependyma disposition at the lateral surface of the ventricular cavity. (Images courtesy of E de Oliveira)