Figure 2.

Barrier structure was identified as compact myelin fibre tracts. (A) denotes the transportation barrier between the ISS of the Cn and Tha in control group. The ISF (blue ball) in the Cn flows to the ipsilateral frontal cortex. The ISF in the thalamus is localized in its anatomical division. The communication between the two ISS divisions is prevented due to the barrier structure. The ISS barrier structure between Tha and Cn was identified using histological stain (B-F) and 7.0T MR (I). The ISS barrier structure was confirmed as myelin with versican (D) using HE (E) and fast blue (K), respectively, in which no neuron or neuroglial cell was found. Nissl staining also showed absence of neurons, indicating that the structure was myelin fiber fascicles (C). Myelin integrity was confirmed by Black Gold staining (B). In the oblique sagittal section of rat brain, the boundaries of Cn., ic. and Tha. were not clear and except for ic., which was composed of the myelinated fibres, no other structure was found between Cn. and Tha. (G). The structure in ic was also confirmed as myelin sheaths by EM(H). There were no gap or tight junctions constructed by cell membranes. (I) shows an MR axial image where the barrier structure between Tha and Cn is evident. (K) shows fast blue staining of a coronal slice, where the barrier structure, stained deep blue, was identified as a myelin fibre tract between the Cn and Tha. (J) shows corresponding axial view images with multi-dimensional and stereoscopic reconstruction. The colour-coding of the track density imaging (DTI) indicates the main local orientation of all fiber tracts in the same slice (red: left-right, green: anterior-posterior, blue: inferior-superior). The divisions of Cn are bordered by the internal capsule, external capsule, corpus callosum, and the wall of the lateral ventricle.