Macular hole is a specific disease of the central retina that affects central visual acuity and central visual field. The purpose of this study is to investigate the alteration of visual processing in patients with macular hole who had small central scotoma. Six patients with macular hole participated in this study. We used positron emission tomography (PET) to measure task-related changes in regional cerebral blood flow to identify regions of the brain activated during visual stimulation. Three tasks were performed in each eye: control task, checkerboard task, shape-discrimination task. Checkerboard stimuli caused a greater blood flow activation response in normal eyes than in affected eyes at the occipital cortex. The area involved in the macular hole appeared to be 20 mm or more anteriorly from the . The Shape-discrimination task in affected eyes activated angular gyrus, inferoparietal lobule, and middle frontal gyrus. Our findings demonstrated greater confidence in Horton's new retinotopic map than in Holmes' retinotopic map in cortical areas involved in macular function. The dorsal pathway of the visual system was activated more than the ventral pathway in patients with macular hole.

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We measured the lengths of some parts of the right and left hemispheres (HEs) in 70 formalin-fixed brains and on 15 computed tomography/magnetic resonance imaging (CT/MRI) images (7 left-handed and 8 right-handed cases) to clarify the morphological changes indicating which HE developed earlier and handedness. In many cases of the fixed brains, 1) the distance from the frontal pole to the

was longer in the left HE than in the right HE, 2) the distance from the middle plane to the lateral-most portion of the HE was wider in the right HE than in the left HE, 3) the left elongated more posteriorly and covered the right , and 4) the volume of each HE was nearly the same. The results indicate that the left HE develops and grows slightly earlier in the larger semi-cranium (half of the cranium) than the right HE which develops later in the smaller semi-cranium. The whole brain was more spherical in the female cases than in the male cases. The morphological changes in both HEs for handedness were not evident on the CT/MRI images.

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In order to reexamine the cortical distribution of the callosal connection, as well as its topographical relation to the binocular area in the rabbit visual cortex, the distribution of cortical responses evoked by electrical stimulation of the optic nerve and by direct cortical stimulation of the opposite visual area were studied in thirty immobilized animals.
1. The early response to ipsilateral optic nerve stimulation was similar in latency and waveform to that of the contralateral stimulation, and the area giving this response was determined as the binocular area. The binocular area which was a band of 6-7mm wide extended from the anteromedial to the posterolateral portion across the visual cortex.
2. Besides the early response, the binocular area showed the later response to ipsilateral optic nerve stimulation. The later response was found to be mediated via the corpus callosum, because it was abolished by cooling the opposited visual cortex. The interval between the beginning of the early and late responses was comparable with the latency of the transcallosal response elicited by direct cortical stimulation. The transcallosal response was also abolished permanently by cutting the posterior half of the corpus callosum. The area of transcallosal response and the area effective in eliciting this response were found to be in good agreement with each other and with the binocular area.
3. The callosal connection between the two binocular areas was not necessarily homotopic. For diffusely distributed points of stimulation in the binocular area of one cortex the points showing the maximal callosal responses in the other cortex were arranged in a narrow band in the middle of the binocular area. This band, about 1mm wide and running obliquely about 45 degrees to the midline, seemed to correspond to the projection line of the vertical meridian (decussation line) determined by Thompson et al.
These results suggest that the whole binocular area of both hemispheres in the rabbit are interconnected via the corpus callosum, and that the callosal fibers from the binocular area of one cortex terminate most densely in the middle of the opposite binocular area.

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The morphometric anatomy of the superficial cerebral veins in relation to cerebral gyri was studied in 244 cadaveric cerebral hemispheres. Our morphometry revealed that the position of the central sulcus and that of the parieto-occipital sulcus near the superior sagittal sinus were at 55% and 83.6% respectively of the half-perimeter running from the frontal pole to the (FO) . The drainage position of the central sulcal vein (of Rolando) into the superior sagittal sinus was about 65% of the FO half-perimeter on each side. The three main drainage veins among the superficial cerebral veins are classified into four types: (1) left predominant, (2) right predominant, (3) no laterality, and (4) absent. No laterality predominance was observed regarding the superficial middle cerebral vein (of Sylvius) . The inferior anastomotic vein (of Labbe), however, was predominant on the left hemisphere. The superior anastomotic vein (of Trolard) was observed with similar frequency in each type. In conclusion, the superficial cerebral veins can be classified into eight different types according to venous drainages.

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The present experiment was undertaken to clarify the pathogenesis of primary fatal head injury due to impact and further to obtain a severity index denoting the relationship between the magnitude of impact and the severity of head injury in animals with experimental blunt head injuries caused by simplified impact upon the cranium.
The experiment was conducted on Ketalar-anesthesized rhesus monkeys. Impact was imparted to the animals by means of a 12 in. HYGE impact tester. Before and after the impact the animals were subjected to a series of examinations at intervals, including respiration, ECG, blood pressure, cerebral circulation, partial pressure of blood gases, acid-base equilibrium and EEG. Pathological examination, measurements of lactic acid and monoamine contents in various portions of the brain were also made.
An impact upon the head, at an acceleration in the horizontal antero-posterior direction of 1000-1500 G and a duration of 3-4 msec, proved fatal invariably in animals weighing more than 8 kg (body weight×effective acceleration above 30 kg). In dead animals, primary injury consisting of narrowing of lumen and stoppage of blood flow in perforating arteries of the brain-stem and small hemorrhages in the same areas was noted. It was demonstrated that these changes give rise to central dysregulation of the circulatory (including heart) and respiratory systems which in turn acts on cerebral circulation and metabolism.
This fact not only proves the existence of a primary fatal head injury and further clarifies its mechanism of development but also suggests the possibility of grading the severity of head injury by simplified impact and also by expressing the relationship between the magnitude of impact and the severity of brain damage as a severity index.

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This study investigated whether the optic nerve evoked potential (ONEP) elicited by electrical stimulation of the optic nerve can serve as a reliable intraoperative indicator of visual function. In the experimental study, two silver-ball stimulating electrodes were placed on the dog optic nerve adjacent to the apex of the orbit and one recording electrode was placed on the optic nerve near the chiasm. The nerve was stimulated with 0.1 to 10 mA rectangular pulses. Stable and reproducible ONEPs were obtained. The ONEPs were not influenced by electromyographic potentials and were recorded more clearly on the optic nerve than on the surrounding tissue. Stepwise incremental transection of the thickness of the nerve resulted in incremental amplitude reduction proportional to the transected area. No response was recorded after complete sectioning of the nerve. In the clinical study, recordings were obtained from 15 patients after craniotomy to treat parasellar tumors or cerebral aneurysms. Reproducible ONEPs were recorded intraoperatively from the electrode placed on the optic nerve near the chiasm in 14 of 15 patients. In the remaining patient, the ONEP, recorded only after tumor removal because the optic nerve was stretched and extremely thin, was remarkably small and the patient developed unilateral blindness postoperatively. These experimental and clinical results suggest the possibility of intraoperative monitoring of visual function in patients undergoing craniotomy for the treatment of lesions near the optic nerve.

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The Late Pleistocene fossil human remains (individuals I–IV) of Minatogawa, Okinawa Island are important in addressing the population history of the Japanese archipelago and in understanding evolution of Homo sapiens in eastern Asia. This study is the first on Minatogawa I’s endocranial morphology, based on micro-computed tomography (micro-CT). We digitally reconstructed the Minatogawa I endocast, and created its physical model using a three-dimensional printer system. We compared the Minatogawa I endocast with available H. sapiens and archaic Homo endocasts. We found that Minatogawa I exhibits key derived endocranial features of H. sapiens, such as a highly elevated parietal, endocranial widening confined to a relatively anterior position, and a narrow internal occipital crest. The short, wide, and low proportioned Minatogawa I endocranium lies metrically at the margins of the modern human ranges of variation of this study. The Minatogawa I endocast exhibits a slightly underdeveloped frontal region with marked parasagittal ridges, a weak endocranial parietal boss, and a strong temporal bulge. It differs from Liujiang in the strong expression of these features as well as in overall metric proportions. A weak endocranial parietal boss and a strong temporal bulge are shared by Skhul V and Qafzeh 9, and may represent a primitive condition for H. sapiens in general.

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1. Adult rats (Wistar King A) were used, thirty-seven animals for recording antidromic cortical responses, five for observation of the motor effect of cortical stimulation and three for histological sections of the cerebral cortex.
2. Electrical stimuli were applied to the medullary pyramidal tract in slightly anesthetized rats and the potential changes were recorded at the cortical surface and from various depths of the cortex.
3. The resultant responses of the cortex consisted of an initial sharp positive wave (P I) followed by a secondary small positive wave (P II) and a slow negative wave (N). The P I had the lowest threshold to medullary pyramid stimulation and most faithfully followed the increase in frequency of stimulation up to a frequency of 300/sec.
4. The distribution of the potential changes at various points of the cortical surface evoked with submaximal stimulation to the medullary pyramidal tract was measured. The maximal potential was recorded at a point 6.0 mm anterior from the line connecting the both ears and 3.0 mm lateral from the midline. The amplitude of the waves gradually decreased in the frontal direction from the maximal responsive point, and in the occipital direction it rapidly decreased to an immeasurably small level. The potential at the frontal pole was about one sixth of the maximum. In a lateral direction, the amplitude at a point 2.0 mm lateral from the midline was slightly small than at 3.0 mm and the amplitude both at 1.0 and 4.0 mm was about a half of that at 3.0 mm.
5. The distribution of the antidromic cortical response coincided fairly well with the histological distribution of the pyramidal cell in the cerebral cortex of the rat.
6. Recording from the depths of the cortex, the P I changed its polarity into a negative deflection at about 2.0 mm below the pial surface and the P II changed into a negative potential at a depth of about 1.5 mm. The N decreased to zero and sometimes seemed to reverse into a very small positive wave at about 1.5 mm below the surface.
7. The above results suggest that the P I corresponds to antidromic impulses which invaded the large pyramidal cells in the deeper cortical layers with axons of faster conduction velocity and that the P II is composed of the antidromic impulses of the pyramidal neurons in the more superficial layers with axons of slower conduction velocity. It is considered that the N might represent the potentials of the apical dendrites of pyramidal cells conducting toward. the pial surface.
8. The studies of cortical hemisphere stimulation reveal that the functional motor area occupies a part a little anterior to a location of the antidromic cortical response and the pyramidal cells.
9. The functional significance of the pyramidal tract in the rat was discussed.

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Optic nerve injury or blindness after head trauma has well been known since the days of Hippocrates, and has still remained one of the serious posttaumatic sequelae. Statistically about 2% of head-injured persons suffer from the visual loss and are impelled to have limited social activites³⁾. As the victims of traffic accidents are increasing every year, the studies about this problem are urgent.
Clinical manifestations of the injury of the optic nerve have been well known. The reports of many institutions have shown almost the same results. The summaries are as follows³⁾: There is a constant mode of trauma to make an injury. It occurs frequently in motorcycle accidents. Sometimes it occurs even in trivial accidents, where impact force is not always so large. The blow is usually given to the front of the head. Symptomatologically visual loss occurs immediately after the trauma and is limited usually to the eye on the ipsilateral side to the impact and spares the eye on the contralateral side. Diagnosis is guided from the loss of direct light reflex of the affected side. The fracture of the optic canal is often visualized in X-ray studies. Surgical intervention is not fully effective.
From the pathological view point, there are so many therories as to the causative factors of the injury of the optic nerve. The fracture of the optic canal, the bleeding of the sheath of the optic nerve, and the tearing of nerve fibers are prominent among them. Fracture theory seems most attractive because the fracture of the optic canal is found in 60-90% cases in X-ray studies.
So far, these clinical and pathological data have strongly suggested that mechanical factors play an important role to cause the lesion. However, there has never been a fundamental engineering study. Therefore in this paper, mechnical studies were performed to investigate the mechanism and to clarify the threshold of the impact force of the fracture of the optic canal, which is thought to be closely relevent to the ipsilateral optic nerve injury. The studies were made up of series of experiments.

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In a previous study we investigated the effects of callosal transected lesions made 10 weeks earlier (the 10-week-old callosal transected lesions), either at 3 weeks of age or at 13 weeks of age, upon the acquisition of a black-white (BW) discrimination in rats either with one eye removed at birth (OEB) or at 13 weeks of age (OET) following lesions of the contralateral (CT) visual cortex to the remaining eye. The CT visual cortex lesions were performed right before the training of BW discrimination. We found that the 10-week-old callosal transected lesions facilitated the acquisition in OEBs when the callosal lesions were given at 3 weeks of age, and to a lesser extent at 13 weeks of age. We also found that the same type of callosal transected lesions did not do so in OETs, regardless of the age when the callosal lesions were made.
Since the CT visual cortex lesions inevitably result in damage of the callosal neurons, and lead to de-generation of the callosal afferents in the ipsilateral (IP) visual cortex, the present study was undertaken to investigate if the CT visual cortex lesions made 10 weeks earlier (the 10-week-old CT visual cortex lesions), made either at 3 weeks of age or 13 weeks of age, would affect the acquisition of BW discrimination in OEBs and OETs, like the 10-week-old callosal transected lesions employed in the previous study mentioned above.
We found that in both OEBs and OETs the overall pattern of the facilitation effects of the 10-week-old CT visual cortex lesions on the acquisition of BW discrimination is, in general, the same as that observed in the 10-week-old callosal transected lesions, but the facilitative effect of the 10-week-old CT visual cortex lesions is more prevailing and pronounced. The findings are discussed in relation to the possible involvement of neurotrophic factors, released when the CT visual cortex lesions were made, in synaptic reorganization, and also in relation to the possibility of the increased use of the uncrossed visual pathways.

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Stereoelectroencephalography (SEEG) is a method for invasive study of patients with refractory epilepsy. Localization of the epileptogenic zone in SEEG relied on the hypothesis of anatomo-electro-clinical analysis limited by X-ray, analog electroencephalography (EEG), and seizure semiology in the 1950s. Modern neuroimaging studies and digital video-EEG have developed the hypothesis aiming at more precise localization of the epileptic network. Certain clinical scenarios favor SEEG over subdural EEG (SDEEG). SEEG can cover extensive areas of bilateral hemispheres with highly accurate sampling from sulcal areas and deep brain structures. A hybrid technique of SEEG and subdural strip electrode placement has been reported to overcome the SEEG limitations of poor functional mapping. Technological advances including acquisition of three-dimensional angiography and magnetic resonance image (MRI) in frameless conditions, advanced multimodal planning, and robot-assisted implantation have contributed to the accuracy and safety of electrode implantation in a simplified fashion. A recent meta-analysis of the safety of SEEG concluded the low value of the pooled prevalence for all complications. The complications of SEEG were significantly less than those of SDEEG. The removal of electrodes for SEEG was much simpler than for SDEEG and allowed sufficient time for data analysis, discussion, and consensus for both patients and physicians before the proceeding treatment. Furthermore, SEEG is applicable as a therapeutic alternative for deep-seated lesions, e.g., nodular heterotopia, in nonoperative epilepsies using SEEG-guided radiofrequency thermocoagulation. We review the SEEG method with technological advances for planning and implantation of electrodes. We highlight the indication and efficacy, advantages and disadvantages of SEEG compared with SDEEG.

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A new conceptual framework for understanding hemispheric specialization across evolution is proposed, and its multiple theoretical, clinical, and methodological implications are considered. According to the traditional understanding of hemispheric specialization, the “dominant” (usually left) hemisphere is in charge of language, whereas the “subdominant” (usually right) hemisphere is in charge of non-verbal, particularly visuo-spatial functions. While not incorrect, this understanding cannot be regarded as complete, since it does not permit any consideration of evolutionary continuities. Division of the brain into two hemispheres is not unique to humans ; it is a pervasive feature of the central nervous system throughout evolution. A number of morphological, cellular, and biochemical differences between the hemispheres exists, many of which are shared by multiple species. Therefore, it is only logical to assume that functional differences between the two hemispheres also exist and that they are invariant across multiple species. It is proposed that the fundamental functional difference between the two hemispheres is captured by the distinction between cognitive novelty and cognitive routines. According to this view, the left hemisphere is dominant in cognitive processing guided by previously formed, entrenched representations and strategies. In contrast, the right hemisphere is dominant for dealing with novel cognitive challenges, to which none of the previously formed routines or representations are readily applicable. The distinction between cognitive novelty and cognitive routines is universal and applicable to any organism capable of learning, unlike the verbal-nonverbal distinction which is applicable only to humans. Within this framework, language-mediated cognition is understood as a special case of cognition mediated by previously formed cognitive routines, verbal and non-verbal alike.

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The treatment of arteriovenous malformation (AVMs) depends on the efforts of a multidisciplinary team to provide better results than its natural course. Treatment options are reviewed based on our personal experience series of 208 grade III operated AVMs in a 10-year period. The Spetzler-Martin classification was modified to include subdivisions in the heterogeneous group of grade III AVMs as follows : IIIA(large cortical AVMs), IIIB(small limbic lobe AVMs) and IIIC(small insula lobe AVMs), to augment the surgical resection criteria. The treatment strategy was for most of the cases embolization plus surgery for grade IIIA, surgery for subdivision IIIB and radiosurgery for most and surgery for selected cases of IIIC. The surgical results (good outcome : IIIA 81%, IIIB 86% and IIIC 87%) showed that in spite of the higher surgical and anatomical complexity for the IIIC group in comparison with those IIIB and IIIA AVMs, there are selected cases that can be surgically approached with similar or even better surgical outcomes based on the subdivision proposed. Indeed, these data indicate that the treatment of AVMs can achieve better results when compared to its natural course if managed by a well-trained group of specialists led by an experienced neurosurgeon.

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Craniosynostosis associated with Chiari malformation (CM) is usually found in infants with an underdeveloped posterior fossa. We here present a case of adult craniosynostosis, CM, and symptomatic syringomyelia caused by the protrusion of the posterior rim of the foramen magnum without a tight posterior fossa. A 22-year-old woman with an abnormal head shape and forearm hypesthesia was given a diagnosis of sagittal suture synostosis with CM and syringomyelia caused by foramen magnum stenosis. She underwent foramen magnum decompression with a C1 laminectomy without cranial vault expansion or duraplasty. Her symptoms and radiographical findings improved after surgery. In cases of non-operative craniosynostosis with CM, clinicians should be alert to late-onset syringomyelia and choose surgical strategies according to the pathophysiology.

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The cerebello-pontine angle (C-P angle) is the most common location for meningiomas in the posterior fossa⁹⁾¹²⁾, and the posterior surface of the petrous bone is its most frequent site of dural attachment.²⁾ Two thirds of the meningiomas of the posterior fossa arise at the porus acousticus or just medial to it.¹⁰ The tumor as it enlarges has a predilection for extension into the region of the tentorial notch, causing an upward bulging of the tentorium with rostral protrusion of the upper surface of the cerebellum through the tentorial opening.¹¹⁾ The ease with which large subtentorial tumors with rostro-ventral overgrowth can be approached through a temporal route rather than a suboccipital route⁵⁾⁶⁾ led us to use this simple method of removing the large meningioma of the C-P angle through a large window of the tentorium, from above.

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Damage to the visual cortex or the geniculostriatal pathways could cause homonymous visual field (VF) defects at the contralateral side of the lesion. In clinical practice, it is known that the VF defects are gradually recovered over months on the cases. We report a case with recovered homonymous hemianopia following an infarction in the visual cortex by positron emission tomography (PET) with ¹⁸F-fluorodeoxyglucose (FDG) and ¹¹C-flumazenil (FMZ). A 58-year-old man experienced defect of left VF, and magnetic resonance imaging (MRI) revealed a localized infarction in the right occipital lobe. Goldmann VF perimetry revealed left homonymous hemianopia, but central VF was intact. Three months after the onset of infarction, we measured cerebral glucose metabolism with FDG and FMZ binding using PET. FMZ binding reflects the density of surviving neurons. Moreover, eight months after the onset, FDG-PET scan was performed. Goldmann VF perimetry was also performed at the same times of PET examinations. Decrease of cerebral glucose metabolism in the right anterior striate cortex was observed at three months after onset, while FMZ binding in the same area did not decrease in the patient. At eight months after onset, we observed recovery of VF and improvement of cerebral glucose metabolism in the anterior striate cortex. We presented change of cerebral glucose metabolism using PET accompanying improvement of VF. Evaluation of cerebral glucose metabolism and FMZ binding in the striate cortex is useful for estimating the prognosis of hemianopia caused by organic brain damage.

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3頭のヒツジ(4歳4か月齢から5歳4か月齢)の大脳, 中脳, 橋, 延髄の灰白質と, 大脳白質に海綿状変化が認められた。電顕的に, 海綿状変化は神経細胞および神経膠細胞の胞体における空胞形成, 神経細胞および神経膠細胞の突起の空胞化や腫脹, 軸索周囲腔の拡張ならびに髄鞘の分離に由来していた。神経細胞の胞体の空胞は小胞体と関連していた; 空胞に隣接して小胞体やゴルジ装置が拡張していた。神経細胞および神経膠細胞における空胞形成や腫脹は原発性変化とみなされた。

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