Microelectrode experiments were made on two kinds of cortical cells in the cat, each identified by antidromic stimulation. First, recordings were made from callosal neurons, and these were studied by radial nerve stimulation. Second, recordings were made from pyramidal tract cells (P. T. cells), and the effects of stimulation on the activities of P. T. cells were studied. All studies were carried out in the pericruciate cortex. The following results were obtained;
1) Out of 20 cells identified as callosal neurons, 12 were fired by single stimuli delivered to the superficial radial nerve. The latency of the discharge ranged from 12 to 20msec.
2) Single stimuli to the produced long lasting inhibitory effects on P. T. cells. The inhibitory effect seemed to start with a latency of 20 to 30msec. Though with most cells the effect was purely inhibitory (table 1), on rare occasions a transitory excitation preceded the inhibition.
3) In a few successful intracellular recordings from P. T. cells, a marked hyperpolarization of the membrane was observed to occur when firing was inhibited.

抄録全体を表示

The location of injury was investigated using magnetic resonance imaging in 92 patients. The anatomical relationships in the region around the were also evaluated to clarify involvement in the mechanism of injury in 20 normal volunteers. Lesions in the posterior half of the accounted for 80% of injuries. The falx was increasingly elongated toward the posterior portion of the and the was thinnest at the body-splenium junction in the normal volunteers. The mechanism of injury apparently involves the following factors. The posterior half of the falx is closer to the than the anterior half. Therefore, the anterior part of the easily moves with lateral movement of the cerebral hemispheres, and the strain is likely to be concentrated in the posterior half of the , because the falx greatly limits lateral movement of the hemisphere in the posterior region. The is easily distorted at the thinnest part of the body-splenium junction. Therefore, injury predominantly occurs in the posterior half of the .

抄録全体を表示

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 , 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 . 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 , and that the callosal fibers from the binocular area of one cortex terminate most densely in the middle of the opposite binocular area.

抄録全体を表示

[Purpose] The is the largest fiber bundle in the human brain that connects the two cerebral hemispheres. Callosal motor fiber is known to primarily cross through the anterior midbody of the . However, some reports have shown that callosal motor fibers cross through the posterior body and isthmus. In this study, we evaluated the relative anatomical location of callosal motor fibers related to foot fibers in the and collected quantitative data. [Methods] Fourteen healthy subjects participated in this study. A dataset was obtained utilizing a 1.5 T magnetic resonance imaging (MRI) scanner. For fiber tracking, regions of interest were drawn in the functional MRI activation area and . After the callosal motor fiber tract was reconstructed, we measured its relative anatomical locations in the , and calculated the fractional anisotropy (FA), and apparent diffusion coefficient (ADC) values. [Results] The mean ± standard deviation of the distance ratio was 29.08 ± 3.42%. The values of FA and ADC were 0.54 ± 0.02 and 8.09 × 10⁻⁴ ± 0.22×10⁻⁴, respectively. [Conclusion] We believe that our results present good preliminary data for the determination of the anatomical location of callosal motor fibers in the .

抄録全体を表示

【症例】35歳,女性.【現病歴】数年来の三叉神経痛があり,近医でカルバマゼピン(CBZ)により治療されていた.CBZ1,200mg/日まで増量されるも疼痛コントロールが不良のため微小血管減圧術を施行した.術直後より三叉神経痛は消失したため,CBZを中止した.術後1週間の頭部MRIで脳梁膨大部に異常所見を認めた.MR spectroscopyでは正常組織と同所見であったため経過観察した.3カ月後,MRI上の異常所見は消失した.【考察】抗てんかん薬の突然の中止に伴う脳梁膨大部の一過性MRI異常は,最近の画像機器の進歩により報告が増えてきたが,脳神経外科領域ではまだ十分には周知されていない.不必要もしくは侵襲的な検査や治療を避けるため,本症を十分に認識しておく必要がある.若干の文献的考察を加え報告する.

抄録全体を表示

Objective: There has been reports on the usefulness of diffusion tensor imaging (DTI) about age-or disease-related degradation. DTI is generally evaluated by the region of interest (ROI) methodology. In this study, we applied a statistical way using Statistical Parametric Mapping (SPM) to assess normal aging by DTI and compared results of these two methods.
Methods: Ten young and ten senior normal volunteers were examined. On SPM, tensor images were changed into normalized tensor images. They were compared between the two groups by t-test.
Results: In the senior group, fractional anisotropy (FA) values were higher on the basal ganglia, cingulated gyrus and other cortical gray matter, lower in the corona radiata, internal capsule, centrum semiovale and by using SPM. In the ROI method, the results were almost compatible except in the brain periphery.
Conclusions: Aging changes on water diffusion anisotropy was clearly shown by SPM method which would be useful to evaluate change of water diffusion anisotropy without operator bias even in clinical setting instead of ROI measurement. J. Med. Invest. 52: 186-190, August, 2005

抄録全体を表示

A 6-month-old miniature Schnauzer presented with hypernatremia and clinical signs of vomiting, diarrhea, inappetence, and lethargy. The dog did not consume water on its own. Hypernatremia and the related clinical signs were resolved by fluid administration. Endocrinological investigations and urinalysis excluded the possibility of diabetes insipidus and hyperaldosteronism. Therefore, the dog was diagnosed with hypodipsic hypernatremia. Magnetic resonance imaging revealed dysgenesis of the and other forebrain structures. On the basis of these findings, congenital brain malformation associated with failure of the osmoreceptor system was suspected.

抄録全体を表示

White matter abnormalities have been implicated in psychiatric diseases such as major depressive disorder (MDD) ; however, the underlying mechanisms remain poorly understood. The structure and function of the

are particularly vulnerable to stress, which may lead to MDD. In the present study, we investigated whether chronic social defeat stress (CSDS) induces myelin abnormalities of the through inflammation that contributes to the pathogenesis of MDD. To produce CSDS, the adult C57BL/6J mouse was exposed to an aggressor ICR mouse for 10 consecutive days. CSDS decreased mature oligodendrocytes in the , and persistently developed depression-like behaviors such as increased immobility in the forced swimming test and impaired social interaction. On transmission electron microscopy, myelin abnormalities and axonal degeneration were observed with necrosis-like cell death of oligodendrocytes in the . Interestingly, CSDS significantly increased the Gasdermin D (Gsdmd), a marker of pyroptosis, concomitantly with enhanced IL-1β production in the . Administration of IL-1β inhibitor prevented the decrease of oligodendrocytes and CSDS-induced depression-like behaviors. These findings suggest that IL-1β acts as a crucial mediator of oligodendroglial pyroptosis induced by the CSDS, which may be responsible for the development of MDD.

抄録全体を表示

We examined the objective diagnosis of dementia based on changes in the . We examined midsagittal head MR images of 17 early dementia patients (2 men and 15 women; mean age, 77.2±3.3 years) and 18 healthy elderly controls (2 men and 16 women; mean age, 73.8±6.5 years), 35 subjects altogether. First, the was automatically extracted from the MR images. Next, early dementia was compared with the healthy elderly individuals using 5 features of the straight-line methods, 5 features of the Run-Length Matrix, and 6 features of the Co-occurrence Matrix from the . Automatic extraction of the showed an accuracy rate of 84.1±3.7%. A statistically significant difference was found in 6 of the 16 features between early dementia patients and healthy elderly controls. Discriminant analysis using the 6 features demonstrated a sensitivity of 88.2% and specificity of 77.8%, with an overall accuracy of 82.9%. These results indicate that feature analysis based on changes in the can be used as an objective diagnostic technique for early dementia.

抄録全体を表示

We studied the objective diagnosis of Alzheimer-type dementia based on changes in the . We examined midsagittal head MR images of 40 Alzheimer-type dementia patients(15 men and 25 women; mean age, 75.4±5.5 years)and 31 healthy elderly persons(10 men and 21 women; mean age, 73.4+7.5 years), 71 subjects altogether. First, the was automatically extracted from midsagittal head MR images. Next, Alzheimer-type dementia was compared with the healthy elderly individuals using the features of shape factor and six features of Co-occurrence Matrix from the . Automatic extraction of the succeeded in 64 of 71 individuals, for an extraction rate of 90.1%. A statistically significant difference was found in 7 of the 9 features between Alzheimer-type dementia patients and the healthy elderly adults. Discriminant analysis using the 7 features demonstrated a sensitivity rate of 82.4%, specificity of 89.3%, and overall accuracy of 85.5%. These results indicated the possibility of an objective diagnostic system for Alzheimer-type dementia using feature analysis based on change in the .

抄録全体を表示

 We report on a right-handed 43-year-old policeman with atypical Marchiafava-Bignami disease (MBD). The typical clinical manifestations of MBD are reduced consciousness, confusion, seizures, psychotic and emotional symptoms, hemiparesis, dysarthria, ataxia, and coma and death. However, our patient had not developed any of the above symptoms except for slowly progressive cognitive impairment mimicking that of Alzheimer disease. The incidence of MBD may be higher and its prognosis less severe than generally believed. MBD has been underdiagnosed and underreported, and nonspecific general symptoms and encephalopathy in an alcoholic might indicate undiagnosed MBD.

抄録全体を表示

The sensory projection from jaw muscles to the cerebral cortex have been studied in rats by electrophysiological and histochemical methods. Electrical stimulation of individual masticatory muscles elicited bilateral responses in the cortical areas 8, 10, 2, and 2a. The following pathway was postulated to mediate these cortical responses; impulses of muscle origin are conducted in turn to the trigeminal mesencephalic tract nucleus (TMT), the contralateral thalamic nucleus ventralis posteromedialis (VPM), the cerebral cortex and finally to the other cerebral cortex which is ipsilateral to the side of stimulation. The ipsilateral cortical response appeared about 5 msec later than the contralateral one and was abolished by sectioning the . By stimulating the cerebral cortex antidromically, the conduction time to the VPM was found to be as long as 6 msec. The conduction from the TMT to the contralateral VPM consumed a period of more than 10 msec. It was presumed to be multisynaptic, being based on the finding that horseradish peroxidase injected into the VPM could not be recovered in the contralateral TMT.

抄録全体を表示

A 32-year-old man started building a wooden desk atop Mount Fuji at an altitude of 3,776 m. Over the course of the second day, he developed lassitude and cough and experienced a headache that night; however, he continued to work. He was transported to our hospital with an altered level of consciousness. On arrival, chest radiography revealed increased opacities in both lungs, and magnetic resonance imaging (MRI) revealed a high-intensity signal in the splenium on diffusion-weighted imaging. He received mechanical ventilation following tracheal intubation. His respiratory function improved, and he was extubated on the fourth hospital day. Physical examination showed no motor weakness, and although he responded to verbal commands, he was unable to speak and was unresponsive to visual stimulation. On the seventh hospital day, head MRI showed improvement in the lesion in the splenium, although other signal changes were observed in the body of the

. His verbal responsiveness and voice volume improved on a daily basis. Two months after the incident, he continued to experience mild recent memory disturbance. The patient described in this case report showed delayed signal changes in the body of the , possibly secondary to the onset of microbleed-induced edema.

抄録全体を表示

swelling has been reported to occur after ventriculoperitoneal shunting for long-standing hydrocephalus. This report presents a case of swelling after intraventricular tumor resection. A 34-year-old woman presented with a headache that worsened over 1 month. Magnetic resonance (MR) images revealed a mass lesion in the left lateral ventricle and obstructive hydrocephalus. She underwent subtotal resection with a transcallosal approach. After tumor resection, she had long-lasting status epilepticus followed by consciousness disturbance. T2-weighted MR images obtained 8 hr after the operation showed a hyperintense area in the . The patient then presented with bilateral dilated pupils 14 hr after the operation due to acute hydrocephalus and tension pneumocephalus. An emergent re-craniotomy was performed and a ventricular drain was placed. The patient recovered consciousness 3 days after the operation. However, she experienced progressive swelling 25 days after the operation, which improved since then. Approximately 4 months after the operation, she returned to her usual workplace with no neurocognitive functional decline. Two years later, she was doing well with no radiological abnormal findings except thinning. Thus, swelling can develop not only after shunting for chronic hydrocephalus but also after intraventricular tumor resection. It occurred relatively acutely and there was no decline in intelligence after long-term follow-up. This case suggests that swelling after intraventricular tumor resection is a rare but noteworthy complication that can improve without intervention.

抄録全体を表示

Patients with clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) on the splenium of the

(SCC) present with relatively mild central nervous system disturbances. A 41-year-old man was admitted with fever and headache and, his main symptoms were mild headache and fatigue. There were no neurological focal signs. Brain magnetic resonance imaging (MRI) showed abnormal signals in SCC. We report, for the first time, a MERS patient, detected on MRI, who did not present with central nervous system disturbances. Our experience suggests MERS should be considered as a differential diagnosis in patients with fever of unknown origin.

抄録全体を表示

Diffuse axonal injury (DAI) commonly causes immediate loss of consciousness after head injury. We report the case of a 20-year-old man who was involved in a motor vehicle accident, which his estate car ran into a truck from behind. Although he was alert on arrival at the hospital, his conscious level deteriorated approximately 7 hours after the accident. At this time point, he had a generalized tonic seizure and decorticate posturing of his arms with a Glasgow coma scale (GCS) score of 5. MRI revealed findings consistent with DAI. On the 14th day, his conscious level improved to a GCS of 9 and MRI showed chronic DAI. The patient recovered well with only mild memory deficit at discharge. There are few reports of delayed onset DAI, but in terms of its neuropathology, it is possible for it to occur after the time of injury. DAI is the result not only of direct injuries to the axon membrane and axonal sheath due to shearing force, but also of secondary injury by loss of axon transport. In the emergency department, a diagnosis of DAI should be considered in any patient who has suffered head injury by rotational forces even if there is no loss of consciousness on arrival at the hospital.

抄録全体を表示

We present two cases of a very rare tumor, intracranial lipoma, diagnosed by computed tomography (CT) and magnetic resonance imaging (MRI). In one case, the lipoma was in the superior cerebellar cistern, the other was in the periphery of the . In the case in which MRI was used, identification of the lipoma using a routine MRI examination was difficult. These cases are reported now because the incidental diagnosis of intracranial lipoma is likely to increase due to advanced neuroradiological techniques such as CT and MRI.

抄録全体を表示

T₂-weighted MR (magnetic resonance) images of a 19-year-old woman undergoing concurrent chemoradiotherapy for a nasopharyngeal carcinoma revealed a lesion marked by focal hyper signal intensity in the splenium of the . The lesion was not visible two weeks later. She suffered from malnutrition caused by appetite loss during chemotherapy. We concluded that the lesion revealed by the abnormal signal intensity in the splenium had been caused by malnutrition.

抄録全体を表示

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is a rare hereditary stroke disease. In the present study, a Japanese CADASIL family was first reported with missense mutation of Arg141Cys of Notch3 and a unique lesion of . Upon neuropsychological examination, our case 1 showed only right-handed constructional apraxia associated with lesion. No other callosal disconnection signs were present. Sagittal T2 weighted image of case 1 showed multiple small lesions along with the pericallosal branches from the truncus to the posterior part of the splenium in the . Although detailed mapping of the for functional fractionation in humans remains incomplete, the constructional apraxia on the right may be related to callosal dysfunction from the truncus to the posterior part of the splenium in the .

抄録全体を表示

　AVM of the

は脳梁に発生する稀少な動静脈シャント疾患で，若年者に脳内出血で発症することが多い．繰り返す脳室内出血の原因として報告されることもあり，脳深部の病変のため，治療に伴う合併症も多く，慎重かつ適切な治療選択が重要とされる．今回，我々は繰り返す脳室内出血で発症した高齢のAVM of the 患者を経験し，年齢と全身状態から侵襲的な治療は不適切と判断されたため，流入動脈塞栓術とガンマナイフ治療を行い良好な成績を得た．

抄録全体を表示