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Pineal parenchymal cell tumors (PPCTs) with or without metastasis into the lumbar region by way of the cerebrospinal fluid were treated successfully with combination chemotherapy using cisplatin, vinblastin, and bleomycin (PVB) or cisplatin and vinblastin (PV) and low-dose irradiation (25 approximately 30 Gy). Our series included a case of pineoblastoma, two cases of mixed pinocytoma/pineoblastoma, and a case of pineocytoma, compared to which the data held by the All Japan Brain Tumor Registry (AJBTR) included information on 47 cases pineocytoma and 20 of pineoblastoma. All our patients have survived, with scores of 90% or over on Karnofsky's performance scale, for 2-12 years of follow-up so far; however, the 5-year survival rates of the patients recorded by AJBTR were 83% for pineocytoma treated with radiation and 43% without radiation; and 42% for pineoblastoma treated with radiation and 50% without radiation. Incomplete or varied chemotherapeutic regimens used in different medical centers to treat PPCTs precluded an evaluation such as was made by AJBTR. Our results suggested that combination chemotherapy with low-dose back-up radiotherapy may be the treatment of choice for primary or recurrent disease with or without dissemination in PPCTs.

Thalamic neurons were identified by activity related to passive joint movement, active joint movement, tapping stimulation, and light touch stimulation during surgery to treat movement disorders. The neurons were classified into three types: movement-related neurons, tapping-related neurons, or superficial sensory neurons. Tapping-related neurons had characteristics of lemniscal sensory neurons and occupied the border area of movement-related neurons and superficial sensory neurons. Tapping-related neurons showed a laminar distribution 1.0-1.5 mm in width in the anterodorsal region of the nucleus ventrocaudalis. Results suggest that the distribution pattern of tapping-related neurons in the human thalamus is consistent with the functional distribution pattern found in the monkey thalamus.

Venous malformations in the posterior fossa are relatively rare. Although the introduction of CT and MRI has made them easier to detect, their treatment is still controversial. Based on our experience with six patients and a review of the literature, we have tried to establish guidelines for their treatment. Since they have a benign natural course and may provide venous drainage in the posterior fossa, venous malformation found incidentally, unruptured venous malformation with nonhaemorrhagic complications, and those accompanied by small intracerebellar haematoma of less than 2 cm in diameter due to their rupture, should be treated conservatively unless they are associated with a coexistent malformation. Venous malformation with intracerebellar haematoma larger than 3 cm or reexpansion of the haematoma due to rebleeding should be treated surgically by evacuation of the haematoma. Resection of venous malformations in the posterior fossa should be restricted to cases in which the malformation is small and does not serve as a functional venous drainage route. Radiation therapy, including the "gamma-knife", may be a treatment of choice in the future.

During neurosurgical treatment for the relief of movement disorders, thalamic neurons were identified with activity related to passive joint movement, active joint movement, deep sensory stimulation and superficial sensory stimulation. The cells responding to passive joint movement were located just rostral and dorsal to the cells responding to superficial sensory neurons. This area corresponded not only to Hassler's Vim (ventralis intermedius) nucleus but also to a part of the Vc (ventralis caudalis) nucleus. This distribution mode of cells responsive to passive joint movement was similar to that of the deep sensory neurons in the VPLo (ventralis posterior lateralis oralis) nucleus and in a portion (anterodorsal shell) of the VPLc (ventralis posterior lateralis caudalis) nucleus in the monkey thalamus. Recently, the anatomic and physiologic similarity between the human and monkey thalamic ventrolateral complex has been described. These results confirm the similarity between the human and monkey thalamic ventrolateral complex both anatomically and physiologically and could thus be useful for future studies exploring the neuronal mechanisms of involuntary movement disorders, such as tremor.

✓ A 64-year-old man suffering from crescendo brainstem symptoms due to acute total occlusion of the vertebrobasilar artery was successfully treated by cerebral artery stent placement. The total occlusion of a long segment of the vertebrobasilar artery was completely recanalized by implanting two flexible, balloon-expandable coronary stents. The patient's clinical outcome 30 days later was favorable. No complications occurred during or after the procedure. This therapeutic option may prove to be a useful means to revascularize an acute total occlusion of the vertebrobasilar artery.

Arachnoid cysts are found wherever the arachnoid membrane exists. Therefore, arachnoid cysts tend to occur extracerebrally. A case of an intraventricular arachnoid cyst in a 37-year-old female is reported. The cyst was found in the left lateral ventricle and arose from the choroid plexus. The cyst wall, histologically, consisted of the arachnoid cell lining. Light microscope examination showed the hypocellular membrane without glial tissue. Electron microscope examination showed that the cyst lining cells adhered by an interdigitation with desmosome and the cells had no microvilli. These findings were compatible with the features of an arachnoid cyst.