The microvascular systematic architecture of the cerebral cortex were studied in six rabbits. The internal carotids were injected with Chinese ink via a cannula. After fixation, brains were removed and made sections of 80-220?m thick. Some sections were counterstained with HE or Nissl method in order to observe the histological structure of the microvessels and the relationship between the vessels and the nervous tissue.Morphometric measurements of the microvessels were made according to the Strahler system. Results were as follows.(1) In the cerebral cortex, the microarteries and microvenes could be subdivided in to four orders. (capillaries were considered as O order), Perforating branches were perpendicular to the surface of the cerebral cortex and the distribution area of a microartery trunk was in a columnar shape with a radius of 204.5 ?m. This was in compliance with the size of a functional column of the cerebral cortex.(2) For microarteries from order 1 to 4, the branching ratio was 3.72, the diameter ratio was 1.42, the segmental length ratio was 1.82; while for microvenes from order 1 to 4, the branching ratio was 3.25, the diameter ratio was 1.73, and the segmental length ratio was 2.25.(3) The total length of the true capillary network per unit volume of the cerebral cortex was 5.82?10~5?m/mm~3. The density of the capillary network of the cerebral cortex was highest in fourth and fifth layers, while the first layer was rather scarce in capillary network. The number of neurons within each lattice of the capillary network was most numerous in the fourth layer, 4.36 per lattice.According to the results mentioned above, the functional significance of the microvascular architecture and the microcirculation dynamics of the brain was also discussed.

It was widely received that the parafasicular nucleus (Pf) and the central lateral nucleus of the thalamus played an important role in the mechanism of the acupuncture analglsia. Consequently, it was necessary to make a careful histological observation on pf in order to provide some data for the investigation of the acupuncture anesthesia mechanism. Five adult rabbits, each weighing about 2 kg, were selected for this experiment. The animals were infused with 10% formalin, their skulls were mounted on the stereotaxic apparatus according to the Sawyer's atlas. Brains were removed and made serial sections which were stained alternately with Nissl's method and the silver impregnation method of Glees. The form and size of the Pf was studied with a microprojector, while the diameters of the Pf neurones were measured by a micrometer under immersion microscope. Results were as follows. The diameters of the whole Pf: from dorsal to ventral, were about 1.6～2.2 mm, from anterior to posterior, were 0.9～1.5 mm, the transverse diameters of Pf were about 0.8～1.1 mm. The volume of Pf was about 0.68～1.26 cubic mm. The total number of the neurones in Pf was about 21,000～39,000 unilaterally. The long diameter of the cell soma in Pf was 21.06?6.22?, the short diameter of the cell soma was 11.20?3.28?. The ratio of the long diameter to the short diameter of the cell soma was 1.91?0.84. The area of the cell soma was about 143.28?58.92?~2. The long diameter of the cell nucleus of Pf was 11.74?1.5?, the short diameter of the cell nucleus was 8.02?2.01?. The ratio of the long to short diameter of the cell nucleus was 1.44?0.32. The Pf of the rabbit exhibited primary differenciation. The neurones of Pf could be subdivided into three groups: (1) The first group was formed by large and deeply stained cells which were triangular or pyramidal in shape, and distributed mainly in the lateral inferior portion of the Pf. (2) The neurones of the second group were fusiform in shape, concentrated mainly in the medial portion of the Pf. (3) The neurones of the third group were smaller than those of the first group and stained more lightly, they were shortly ellipsoidal in shape and distributd chiefly in the lateral superior portion of the Pf. Statistical analysis showed that there were some differences among the cells in different portions of the Pf. The authors suggested that the large and deeply stained neurones in Pf were quite similar to those of the central lateral nucleus and might belong to pain sensitive neurones.

Nine adult rabbits, perfused with 10% formalin, were used in this experiment. Five of them were mounted on the stereotaxic apparatus according to the Sawyer's atlas. Brains were removed and made serial sections including thalamus and hippocampus. The neocortices of the other four rabbits were removed and the hippocampal formations were exposed. Serial sections of the hippocampus were made and stained alternately with Nissl's method and the silver impregnation method of Glees. The results could be summarized as follows.1. The hippocampus measured 28.00-36.00 mm in length, 6.00-8.50 mm in breadth and 2.68-3.39 mm in thickness. The total numbers of the pyramidal cells (CA_1-CA_4), the granular cells in the dentate gyrus and the basket cells were 7.36?10~6, 4.93?10~6, 2.40?10~5 respectively. The ratio of the total numbers among the pyramidal, granular and the basket cells was 30:20:1 approximately. The total number of the CA_1 pyramidal neurones was 4.11?10~6, and that of the CA_3 was 2.48?10~6. The ratio of the numbers of the CA_1 and CA_3 neurones was 1.66:1.2. The arrangements of the granular cells in the dentate gyrus and the apical dentrites of the CA_1 neurones were rather regular and possessed a typical array-like structure.3. The total numbers of the fibers in the column fornix (FN)and the mamillothalamic tract (MT) were 83700 and 58740 respectively. MT:FN=1:1.42. The total number of the neurones in the mamillary nucleus was 113500, and that of the anterior thalamic nucleus was 165600. The ratio of the neurones between these two nuclei was 1:1.46.According to the results mentioned above, the functional significance of the characteristic structure of the hippocampus was also discussed.