They than reach the supramarginal gyrus from where they

course anterior in the depth to join the association XL184 concentration fibres of the insula that ascend from the operculum. In the temporal lobe, the most anterior fibres descend from the inferior aspect of the angular gyrus towards the second [middle] temporal gyrus and form the floor of the superior temporal sulcus, which at this point is often interrupted by a small vertical gyrus. The stratum verticale convexitatis is also strongly developed in the monkey and has been described as fasciculus occipitalis perpendicularis by Wernicke (as previously cited, p. 23). Similar to the sagittal sulci, both vertical sulci, namely the anterior occipital sulcus and the ascending branch of the superior temporal sulcus,

are encapsulated by a very thin groove of longitudinally directed short association fibres. In the ABT-263 molecular weight precuneus, the layer of fibres adjacent to the cortex, namely the stratum proprium praecunei, also has a vertical direction and encapsulates the posterior elongation of sulcus callosomarginalis in dorso-ventral direction. More medially located fibres bend anteriorly at their inferior terminations and join the dorsal part of the cingulum whose detailed description is yet outstanding. The deeper these fibres run, the farther anterior they penetrate the cortex of the gyrus fornicatus [the upper limb is the cingulate gyrus and the lower limb is the parahippocampal gyrus]. A third layer of vertically directed fibres is formed by the fibres previously described as belonging to the anterior medial part of the stratum sagittale externum and joining the descending part

of the ventral cingulum reaching the temporal lobe. The second mentioned layer belongs to the anterior part of the precuneus, whereas the third belongs to its posterior part. Subsequently, fibres of the corona radiata follow that ascend towards the hemispheric margin. In the anterior region of the occipital lobe and at the transition to the parietal lobe, Lepirudin where the stratum cunei transversum terminates, it remains a white matter system surrounded by the stratum proprium praecunei medially, the stratum verticale convexitatis laterally, and the stratum sagittale externum ventrally. This system abuts the superior part of the stratum sagittale externum like a roof ridge and consists mainly of fibres that run in a longitudinal cranio-caudal direction. This fibre system is only clearly visible on fresh coronal sections of a brain hardened in the Müller solution. It appears as a brighter area, which abuts the stratum sagittale externum like a cap and is distinguishable from the deep dark transvers cut of the latter, whilst it becomes gradually indistinguishable towards the dorsal and lateral white matter of the stratum proprium corticis.