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Depression has been known to reduce the prefrontal activity associated with the execution of certain cognitive tasks, although whether a temporarily depressed or anxious mood in healthy individuals affects the prefrontal blood oxygen level during cognitive tasks is unknown. Combining the measurement of prefrontal activity with near-infrared spectroscopy (NIRS) and the two cognitive tasks, namely the letter version of the verbal fluency test (VFT-l) and the Stroop test, we measured the effect of a depressed or anxious mood and gender on the changes in the prefrontal oxygenated hemoglobin (Oxy-Hb) levels during those cognitive tests in healthy individuals. Depressed mood or anxious mood was assessed by the Hospital Anxiety and Depression Scale (HADS). Thereby we aimed to explore the possibility of NIRS measurement for detecting the early subclinical manifestation of major depression. Moreover, we examined the possible relationships between prefrontal activation and the functional Val66Met polymorphisms of the brain derived neurotropic factor (BDNF) gene and serum BDNF level. As a result, the increased prefrontal Oxy-Hb levels during cognitive tasks were significantly correlated with the severity of depressed mood in males. The course of the prefrontal Oxy-Hb increase was different depending on the cognitive tasks, i.e., the VFT-l or the Stroop test, in both genders. Correlations of BDNF genotype and serum BDNF level with the prefrontal Oxy-Hb levels during those cognitive tasks were negative. Our results suggest that the early subclinical manifestation of depressed mood in males might be detected by the NIRS measurement, which is not correlated with the individual properties of BDNF.

Quantitative analysis was tried for cognitive functions for 115 volunteers, aged 21 to 88 years. Reaction time (RT) was used for visual (V-RT), auditory (A-RT), vibratory cues (V-RT), right-left-orientation cognition (RL-RT), and short-term-memory cognition (STM-RT) for the same subjects. Subjects were asked to judge a cue presented whether the right or left side and push a button at the same side as the cue presented, as for V-RT, A-RT, and V-RT. Subjects were asked to read sentences as “Push the right/left button, or Push the same button as the previous instruction" and RTs were measured for the former sentence as for RL-RT, and the latter sentences for STM-RT. RTs were analyzed with the exponential regression, and all RTs increased with increasing age significantly. Mean RT and standard deviation was 0.48±0.17sec for V-RT, 0.44±0.28sec for A-RT, 0.51±0.20sec for V-RT, 9.12±4.01sec for RL-RT, and 5.26±2.45sec for STM-RT. The analysis of variance showed significant among RTs (P

For near infrared red spectroscopy (NIRS), the debate over the reliability of its absolute value is ongoing, and discussed in this paper with alpha-blocking task. The purpose of the study is step by step clarification on NIRS reliability. The method in this paper is the evaluation with a task that is clinically important and has achieved a wide consensus and a diagnostics of its measurement. From this viewpoint, this paper discussed the NIRS measurement, with the electroencephalography (EEG) measurement of alpha-blocking as the task. Based on the EEG measurement results of alpha-blocking, we investigated the characteristic changes in the NIRS measurements; a correlation between the two measurements was found (0.806), based on alpha-rhythm patterns of EEG and the increasing or decreasing patterns of oxygen metabolism on NIRS. In addition, a correlation was found between complexities in the two measurements (0.677). The variation level of the complexity in the EEG measurements was 7.14 times larger compared with that of NIRS on average which suggests that the EEG measurements included much information than the NIRS measurements for alpha-blocking task. Despite, the correlation results suggest a possibility of NIRS application to alpha-blocking diagnosis. These numericals contribute to step by step clarification on NIRS reliability.

【Purpose】To find automated diagnosis of retinopathy, the matched filters (Chaudhuri et al, 1989) were studied for retinopathy. The filters had been reported for a film-based fundus image of 2.5x105 pixels, and the image needed to be converted into a digital file with an image scanner. Now, direct digital images are available with more precise images than 107 pixels.【Methods and Subjects】Non compressed digital images were taken with a non mydriasis-type fundus camera, and images of green component were used. Fluorescein angiography was done for retinopathy, and the images were compared to the matched filters. Subjects were 11 normal volunteers and 25 patients with typical diabetic retinopathy, 7 patients with branch retinal vein occlusion, 18 patients with age-related macular degeneration, respectively.【Results】Fine retinal blood vessels, microaneurysms, neovascularization, dotted retinal bleedings and exudates were emphasized for diabetic retinopathy, but non-perfusion areas in fluorescein angiograms could not be made clear with the filters. 【Conclusion】The filters would be helpful for diagnosis of retinopathy, but the process could not alternate with fluorescein angiography. The filters were not good for the diseases of transparent part such as cataract or vitreous hemorrhage.

The aim of this study was to develop a novel quantitative method for examining the cube copying test. The analysis has been only through qualitative observation for the test. Therefore we applied a quantitative method to analyze cube copying test results. Figures were digitized and their symmetry was studied to determine correlation coefficients (CCs). This study included 19 elderly subjects (68-92 years) who complained of memory disturbance or being afraid of dementia, and 9 younger subjects (21-60 years) who visited our hospital with minor head trauma or dizziness. Six CCs were examined between the sample and drawn figures, between the drawn figure and 180°-rotated drawn figure, between the left half and right half of the drawn figure, between the upper half and lower half of the drawn figure, between a quadrant and an opposite 180°-rotated quadrant of the drawn figure. All CCs were significantly low for the elderly group. The elderly group also showed mild deterioration in the Hasegawa's Dementia Scale (21. 1/30) and CT findings with cortical and/or ventricular dilatation and lacunae. No neurological deficit was noted for the younger group. Our quantitative method may be useful for evaluating not only constructional apraxia but also dementia and mild cognitive impairment.

The risk to fall has clinical relevance in prognosis of elderly people. We analyzed aging effects on the physiological properties of the vertical ground reaction force of healthy subjects and examined whether it can be used as an index for postural instability and risk to fall.We analyzed stabilometric data from 1795 healthy volunteers (3 - 93 years old). Vertical acceleration was computed from the load-cell records and underwent frequency analysis. The multiple comparison test was performed by age groups at every frequency within the detected significant band.Variances in vertical acceleration were high in juveniles and elderly people. Both acceleration power at 1.5-2 Hz and power ratio of eye closure to the open eye at 2-6 Hz were markedly high and decreased by 20 years of age. Age groups from 20 to 60 years had low stable power profiles and the age groups over 60 years showed increased power at 5-8 Hz relative to aging.Our findings suggest that the postural instability of young people evoked by eye-closure accounts for 3-Hz vibration and that increased power in elderly subjects around 6.5 Hz has a strong correlation with aging.

Postural control in standing balance was analyzed in 80 volunteers, aged 31 to 92 years, who were free from equilibrium disease. Center of foot pressure (COP) was measured on a horizontal plane and in a vertical direction, during 20 sec with eyes open and 20 sec with eyes closed. COP-path length and COP-path area were obtained on the horizontal plane, and coefficient of correlation was tested for them with age, body weight and height. Integrated power between 0 and 10 Hz was tested for the horizontal medial-lateral oscillation, horizontal anterior-posterior oscillation, and vertical oscillation. Age was correlated with COP-path length and COP-path area, but body weight and height were not correlated with them. Age was correlated with the powers in the medial-lateral oscillation with eyes open and closed, and in the anterior-posterior oscillation with eyes closed. Body weight and height were correlated with the powers in the anterior-posterior oscillation with eyes closed and in the vertical oscillation with eyes open and closed. Conclusively, vision was important to the postural control for aged people, and the medial-lateral oscillation might increase with aging. Vertical oscillation correlated to body weight and height, which suggests important weight control for aged people.

To determine the synaptic source of the respiratory-related activity of laryngeal motoneurons, spike-triggered averaging of the membrane potentials of laryngeal motoneurons was conducted using spikes of respiratory neurons located between the Bötzinger complex and the rostral ventral respiratory group as triggers in decerebrate, paralyzed cats. We identified one excitatory and two inhibitory sources for inspiratory laryngeal motoneurons, and two inhibitory sources for expiratory laryngeal motoneurons. In inspiratory laryngeal motoneurons, monosynaptic excitatory postsynaptic potentials were evoked by spikes of inspiratory neurons with augmenting firing patterns, and monosynaptic inhibitory postsynaptic potentials (IPSPs) were evoked by spikes of expiratory neurons with decrementing firing patterns and by spikes of inspiratory neurons with decrementing firing patterns. In expiratory laryngeal motoneurons, monosynaptic IPSPs were evoked by spikes of inspiratory neurons with decrementing firing patterns and by spikes of expiratory neurons with augmenting firing patterns. We conclude that various synaptic inputs from respiratory neurons contribute to shaping the respiratory-related trajectory of membrane potential of laryngeal motoneurons.

Information volume, evoked potentials and reaction time with voice were studied for reading Japanese cursive syllabary “HIRAGANAs”. Thirty-two EEGs with a filter from DC to 100 Hz were sampled at 2 kHz into 24 bits during 1000 ms after displaying HIRAGANAs. Evoked potentials were marked over the frontal and occipital areas, because of referring to scalp central areas, then the potentials were converted with the current source derivation. Reaction times for voice were 623±137 for one HIRAGANA, 819±136 for two HIRAGANAs, 993±169 ms for four HIRAGANAs. Broad central areas showed graded different potentials between reading silently and aloud, corresponding to the volume of the information, after 100 ms before 500 ms displaying HIRAGANAs.

In order to investigate the influence of shot peening on the surface durability of case-hardened steel gears, the case-hardened steel gears shot-peened with different shot velocity and shot diameter were fatigue tested using a power circulating type gear testing machine. The hardness, the compres sive residual stress and the surface roughness of the gears increased by the shot peening. The failure mode of all the test gears was pitting. The surface durability of the gear shot-peened under medium condition in this experimental range was higher than that of the non-peened gear, on the other hand those of lightly or strongly shot-peened gears were as much as that. Judging from the pmax-N curves and also the [A (σy/√3 HV)] max-N curves, it is denoted in this experimental range that the surface durability of case-hardened steel gears was influenced by the hardness and the surface roughness of the gears. Therefore, it is proposed in this experimental range that the medium shot peening condition, that is, 60 m/s shot velocity and 0.6 mm shot diameter, should be selected in order to improve the surface durability of case-hardened steel gears.

To study cerebral cortical function in equilibrium, cortical oxyhemoglobin saturation rate was measured during Caloric test for five volunteers. Near-infrared spectroscopy (NIRS) measuring backscattered reflection is a non-invasive, good method to study human cortical activation. Over both temporal areas, the oxyhemoglobin saturation rate changed during the irrigation to the auricle, the irrigation to the ear meatus, and during nystagmus. Caloric test induced various cortical activation; e.g., the sensation in irrigating iced water, vestibulo-autonomic response, vestibulo-ocular response, anticipation to the stimuli and so on.

中枢神経を介した鍼灸の治療効果を調べることを目的に、鍼灸刺激により生じる中枢神経の局所活動を人の脳で調べる方法について紹介する。鍼灸刺激は感覚刺激として入力され、中枢神経で処理される。この時の脳の応答を調べる方法として脳波が広く用いられてきた。しかし、脳波を利用した方法は中枢神経の活動場所を特定する点で問題があった。この問題を解決するために、神経の電気活動に伴って発生する微弱な磁場を空間的に並べられた受信コイルで捉え、磁場発生源の位置を推定するMEG法、この神経活動に伴い変化する血液中のオキシヘモグロビンとデオキシヘモグロビンのそれぞれを、近赤外光の吸収スペクトルの差から分離して捉える赤外分光法、さらに、血液中に生じたデオキシヘモグロビンが持つ磁化率変化を信号強度に反映させた脳機能核磁気共鳴画像 (fMRI) 法を取り上げ、中枢神経における局所活動について調べる方法を紹介する。

Objectives : The objective of the present study is to investigate the relationship between C-fiber nociceptor sensitivity and skin sympathetic nerve activity during mental arithmetic. Methods : Single afferent C-fibers were identified simultaneously with spontaneous postganglionic sympathetic discharges and recorded from the peroneal nerve using microneurography in 23 normal subjects. Mechanical and heat thresholds were measured by ‘marking’ the nociceptor with suprathreshold stimuli, causing increased latency after a subsequent threshold stimulus at rest and during mental arithmetic. Skin sympathetic nerve activity was estimated by counting the number of bursts per minute. Results : Thirty-two single C-fibers were identified. Eleven had polymodal receptors (mechanical and heat sensitive), eight were only sensitive to mechanical stimuli, two were only sensitive to heat stimuli, and 11 were insensitive to both. C-fibers were selected when the ratio of skin sympathetic nerve activity during mental arithmetic to that at rest was over 1.00. In 19 selected mechanical sensitive units, average mechanical threshold was 4.86 at rest and 4.84 during mental arithmetic. In 6 selected heat sensitive units, average heat threshold was 45.0°C at rest and 43.4°C during mental arithmetic. However, differences were not statistically significant. Conclusions : Physiological sympathetic stimulation did not affect afferent C-fiber nociceptor sensitivity to mechanical and heat stimuli in healthy subjects.

To investigate the gamma band activity relating to the discrimination process and motor behavior in the human brain, the event-related dynamics of the EEG spectrum was calculated during the visual GO/NOGO hand movement task and a control task (the visual element of the GO/NOGO task only) in eight subjects. The subjects were instructed to push (GO) or not to push (NOGO) a microswitch according to different visual stimuli and 21-channel scalp EEGs were recorded. The time courses of the power spectra after the stimuli were calculated using the fast Fourier transform for each condition (GO, NOGO and the control task), and were compared statistically between the conditions. The results suggested that a high gamma band oscillation, occurring at the frontal and left parieto-occipital areas at around 90 ms after the stimuli, relates to the discrimination process. Under the GO condition, this oscillation continued until 140 ms, and a subsequent oscillation occurred over the motor areas at around 200 ms, which seemed to be related to the motor action. On the other hand, under the NOGO condition, a low gamma band oscillation occurred in the central area at around 230 ms, which seemed to be related to the inhibition process.

To investigate the functional connection of brain areas under motor inhibition, the event-related coherence (ERCoh) of the electroencephalogram (EEG) was calculated for 10 subjects who were asked to perform a visual discrimination (GO/NO-GO) task. The subjects were instructed to push (GO) or not to push (NO-GO) a micro-switch according to different visual stimuli. Twenty-one-channel scalp EEGs were recorded and the surface Laplacians were calculated at F3, F4, C3, C4, P3 and P4 using the source derivation method. The time-courses of the inter- and intra-hemispheric coherence were calculated using the fast Fourier transform for each condition (GO or NO-GO), and were compared statistically between the two conditions. The results suggest that the ERCoh under the NO-GO condition consisted of two components; α band synchronization between bilateral frontal areas and θ band synchronization among bilateral frontal, central and parietal areas. It is likely that the former is related directly to the decision not to move, and the latter is related to the motor inhibition process.

Binocular interaction for a central field was studied with transient scalp visual evoked cortical potentials (VECPs) using two light-emitting-diodes. VECPs were obtained for binocular and monocular visions with dominant and non-dominant eyes, and arithmetical sums of monocular VECPs with dominant and non-dominant eyes were calculated. Amplitude and latency of remarkable initial three peaks were tested with the multivariate analysis of variance. Significant differences were noted among the four VECPs. Pairwise comparisons showed that (1) the amplitude of the first peak for the binocular VECPs was larger than that for the monocular VECPs but smaller than that for the sum-VECPs; the latency of the first peaks for the binocular VECPs were earlier than that for the monocular VECPs with the non-dominant eye; (2) the amplitude of the first negative peak for the sum-VECPs was larger than that for the binocular VECPs, and the peak latency for the sum-VECPs showed later than that for the binocular VECPs; (3) the amplitude of the second positive peak for the binocular VECPs and monocular VECPs with the dominant eye was larger than that with the non-dominant eye, but smaller for the binocular VECPS than that for the sum-VECPs; the latency for the binocular VECPs showed earlier than that for the monocular VECPs with the dominant eye and for the sum-VECPs. Binocular suppression was noted in amplitude for the three peaks and binocular facilitation was noted in latency for the latter two peaks.

Event-related coherence of the EEG was calculated for 10 subjects performing a visual discrimination GO/NO-GO task. The subjects were instructed to push (GO) or not to push (NO-GO) a button according to visual stimuli. Twenty-one-channel scalp EEGs were recorded and the surface Laplacian was calculated using the source derivation method. The time courses of the coherence between F3 and F4, C3 and C4, and P3 and P4 were calculated using the fast Fourier transform for each task and were compared between conditions. Statistical analysis showed that coherence in the NO-GO condition became significantly higher than that in the GO condition between F3 and F4. The synchronization between bilateral dorsolateral frontal areas might therefore play an important role in the motor inhibition process.

We recorded visual evoked potentials (VEPs) elicited with high or low imaginable Chinese characters (HIC or LIC), representing concrete objects or absolute concepts, respectively. A closed circle (CC) acts as control stimulus. These were displayed (at 1.6 degrees visual angle) for 35 ms on a TV monitor. Twenty-one channel VEPs (band-pas filter: 0.05-60 Hz), using balanced non-cephalic electrodes, were recorded from -100 to 924 ms for 11 right-handed male volunteers. The VEPs were analyzed by multivariate analysis of variance (MANOVA) and comparison of topographies at four remarkable peaks (P110, N160, P230 and N320). MANOVA showed significant differences (p0.001) for both conditions of channel and stimuli (HIC, LIC or CC). P100 for the CC-VEPs, N160 for the HIC- and LIC-VEPs, P230 for the CC-VEPs, and N320 for the HIC-VEPs were remarkable in the posterior scalp regions. Topographies at P100 and N160 showed no difference between the HIC- and LIC-stimuli. However, those at N320 showed difference between the HIC- and LIC-stimuli over the occipital and posterior temporal areas. Those results suggest that the responses at P100 and N160 might segregate Chinese characters from non Chinese characters. N320 suggested certain processes in imagery on recognizing Chinese characters over the occipital and posterior temporal areas.

We studied precise spectra of evoked EEGs in the word recognition analyzed with multiple band-pass filters (MBFA). The filter was infinite impulse response in 2nd order. Firstly, a signal swept from 5 to 100 Hz sine wave was tested with MBFA, fast Fourier transform and Wavelet transform. Ten evoked EEGs with word visual stimuli were recorded from three volunteers. The EEGs were sampled at 1 kHz in 14 bits for 1 s, and were analyzed with MBFA to make spectra from 5 to 100 Hz, and the spectra were averaged 10 times for observation. Evoked powers were noted at alpha band over the occipital area and suppressed powers were noted at beta and alpha bands afterward. Gamma bands were noted to be evoked over the posterior central area in the normalized Event-related spectra.

The semantic processing involved in the visual perception of Chinese characters (Kanji) was studied using electroencephalograms. Thirty concrete Kanji, 30 absolute Kanji and a closed circle were used in a tachistoscopic presentation, wherein one character or a circle was displayed at random for 35 ms, and visual evoked potentials were recorded. The test subjects were11 native Japanese speakers. The concrete Kanji were familiar objects and highly imaginable characters such as a dog, a cat, a cow, etc. The absolute Kanji were familiar Kanji but represented concepts that are difficult to imagine, such as nothing, what, existing, et cetera. P100, N160, P230, and N320 were noted on the evoked potentials. The bilateral posterior temporal lobes and the bilateral occipital lobes were activated for the concrete Kanji at approximately 320ms after the onset of the visual stimuli (P

Most of the reports on visual evoked cortical potentials have dealt with peak latency or amplitude. An early negative deflection at about 20 ms, however, was reported to coincide with the initial signal to the monkey cortex. We studied the initial signal to the human cortex in nine volunteers by taking into account prestimulus fluctuation. Visual evoked cortical potentials were recorded for an interval 10 ms before and 92.4 ms, after a flash stimulus, by means of a neck reference. The amplitudes of the response before the flash stimulus and at each succeeding 5-ms interval after the stimulus were tested with a t-test. The grand average of the visual evoked cortical potentials showed an initial negative peak at 22.3 ms over the frontal poles, a second negative peak at 52.4 ms over the central area, and a third negative peak at 74.7 ms over the occipital areas. The topographic maps corresponding to the peaks of the visual evoked cortical potentials were the same as those of the dynamic t-values. The visual evoked cortical potential and t-values with the bipolar and source derivations showed a marked response beginning around 40 ms over the posterior head. This statistical analysis is an easy method to standardize evoked potentials and to identify deflections.

To examine the possible role of endothelin and vasospasm in eclamptic seizures, we studied and analyzed the electroencephalograms (EEG) of endothelin-1 (ET-1)-treated pregnant, nonpregnant and sham control (dextrose-treated) rabbits. After multiple intravenous bolus injections of ET-1 (500 pmol/kg) or 5% dextrose in the rabbits, we recorded EEG directly from the brain cortex and analyzed by Fast Fourier Transform (FFT). Water content was measured in the brain of all groups (n = 7). Repeated seizures occurred in all of the pregnant and 2 of the nonpregnant rabbits by variable doses of ET-1. FFT analysis showed remarkable changes in frequency and power arrays characterized by mild to severe form of dysrhythmia, high-voltage spikes, high-voltage fast and slow waves after ET-1 injections. Water content was increased in brain mass in ET-1-treated rabbits (p = 0.001) suggesting an ET-1-induced edema. Histologically we confirmed that ET-1 caused ischemic changes in brain tissues. However, ET-1 induced more pronounced changes in behavior, EEG, brain edema or ischemia in pregnant than in nonpregnant groups. The injections of exogenous ET-1 into the brain substances were strongly suggested by immunohistochemical study with polyclonal antiendothelin antibody in brain tissue sections. Therefore, we assume that endothelin along with other vasoactive substances causes acute cerebral vasospasm and ischemia inducing EEG changes leading to ultimate clinical convulsions in eclampsia.

We hypothesized that the immunological reaction against extravasated blood might play a role in the development of vasospasm after subarachnoid hemorrhage. Under the hypothesis, we had reported significant therapeutic efficacy of cyclosporin A on vasospasm in canine models. We here investigated the efficacy of a new, potent immunosuppressant, FK-506, on vasospasm in animal models. Dogs were randomly classified into sham operated, subarachnoid hemorrhage treated-1 group, (FK-506, 0.3 mg/kg-d, intramuscular injection), and treated-2 group (FK-506, 0.15 mg/kg-d, intramuscular injection). Levels of the third factor of complement (C3) and the activity of serum complement inducing 50% hemolysis of sheep erythrocytes (CH50) in serum were also determined. In the treated groups, the levels of FK-506 in serum were monitored. As for C3 and CH50, there were no statistically significant differences among the groups and there were no changes between Day 1 and Day 7 in any group. Angiographical diameters of a basilar artery on Days 1 and 7 were measured with a computed image analyzer, and the extent of vasospasm was compared among the groups. Statistically significant differences between the sham-operated group and the other three groups were noted. However, under sufficient levels of FK-506 in serum, the extent of vasospasm in either treated group was the same as that in the subarachnoid hemorrhage group. These results indicate a significant discrepancy in the therapeutic mechanism for vasospasm between cyclosporin A and FK-506. They have common aspects in the immunosuppressive mechanism. However, in T-cell suppression, the different mechanism in situ between the two drugs is also postulated.(ABSTRACT TRUNCATED AT 250 WORDS)

The protein kinase C (PKC) and calmodulin systems each play a role in vascular contraction. However, the correlation of these two systems in producing contraction has been unclear. To clarify the pathophysiology of vasospasm after subarachnoid hemorrhage, the authors demonstrated tonic contraction of the cerebral artery in a study of isometric tension, and investigated the correlation of the PKC and calmodulin systems in producing the contraction. To develop better management for vasospasm, they also examined the effect of calmodulin antagonists on tonic contraction. The development of isometric tension in canine basilar arteries was measured, with the following results: 1) tonic contraction was dependent on the PKC system, but initiation of the contraction by the calmodulin system was necessary for the subsequent PKC-dependent tonic contraction; 2) specific calmodulin antagonists like chlorpromazine and pimozide partially inhibited the tonic contraction associated with PKC activation; 3) another calmodulin antagonist, trifluoperazine, inhibited the PKC system as well. On the basis of these results, the authors conclude that the PKC system plays a role in the development of vasospasm. In the early phase of contraction, the calmodulin system contributes to the subsequent fully-activated, PKC-induced tonic contraction. To manage vasospasm, a specific calmodulin antagonist would therefore not be sufficient. Suppression of both the calmodulin and PKC systems with trifluoperazine in the earliest stage of vasospasm is recommended.

A 14-year-old boy presented with cerebellar ganglioglioma manifesting as severe headache and confusion. Computed tomographic scans showed a huge, partly enhanced cystic cerebellar tumor. The tumor was totally removed. Histological examination disclosed glial cells and mature ganglion cells. The latter were identified by Nissl's staining and immunostaining for neurofilaments. Ganglion cells were present in the cerebellum and the surrounding subarachnoid space. This heterotopic growth of ganglion cells enabled a firm diagnosis of cerebellar ganglioglioma.

A line-drawing test was standardized for normal subjects to examine effects of normal aging. For this purpose, the results of the test for 168 normal volunteers were quantified using a digitizer and a microcomputer across ages from 9 to 78 yr. Three sets of parallel vertical lines were presented to every subject, the distances between the parallel vertical lines (5. 10, and 15 cm) differed in the three sets. A subject drew an horizontal line starting exactly on the left vertical line and stopped exactly on the right one, and the computer could detect minute inaccuracy at the start and at the stop, which inaccuracy was expressed in mm. In this study, effects of four parameters were evaluated, i.e., ages, sex, distances from the paired vertical lines, and order of trials; all were nonsignificant. The normal range of the deviations was within 2.1 mm (average + 2 SD).

The authors report a case of a cerebellopontine (CP) angle lipoma with a very unusual histological appearance. The 38-year-old male patient suffered vertigo, left tinnitus, and left hearing disturbance. Computed tomography and magnetic resonance imaging showed a nonenhanced low-density area and a high-intensity region in the left CP angle, respectively. The tumor, which was only partially removed because of its tight adhesion to the VIIIth nerve and brainstem, consisted of mature lipocytes and contained a piece of cartilage, which is highly unusual.

Differences in auditory evoked potentials with meaningful words and their reverse playback may reflect different neural processes in recognizing auditory Stimuli. Auditory evoked potentials with the words and their reverse playback were analyzed for eight volunteers, and a maximal difference was observed at a latency around 400 msec. over the left middle temporal central area.

Accurate localization for the process of recognition of a light stimulus is yet to be determined. We studied 19-channel VEP from nine healthy volunteers, evoked by physiologically faint light less than 200 Cd/m2, using a light emitting diode (5 mm phi, 0.3 degrees, energized for 5 msec). VEP was bandpass filtered from 0.16 to 120 Hz, and analyzed from 20 msec pre-stimulus to 184.2 msec post-stimulus. The grand average VEP suggested an initial positive peak at 115.8 msec at the frontal poles and at 136 msec over the occipital areas. An initial negative peak was noted at 156 msec at the frontal poles and at 179.2 msec over the occipital areas. This might suggest that the potentials evoked had propagated from the frontal poles to the occipital areas, taking about 20 msec. However, the topographic maps contained little evidence for such a propagation, but rather indicated the waxing and waning of positive or negative extremes.

The fast Fourier transform (FFT) is a good method to estimate power spectral density (PSD), but the frequency resolution is limited to the sampling window, and thus the precise characteristics of PSD for short signals are not clear. To relax the limitation, a multiple band-pass filter was introduced to estimate the precise course of PSDs for flash visual evoked potentials (VEPs). Signals were recorded during −200 and 600 ms using balanced noncephalic electrodes, and sampled at 1,000 Hz in 12 bits. With 1 Hz and 10 ms resolutions, PSDs were estimated between 10 and 100 Hz. Background powers at the alpha- and beta-bands were high over the posterior scalp, and powers around 200 ms were evoked at the same bands over the same region, corresponding to P110 and N165 of VEPs. Normalized PSDs showed evoked powers around 200 ms and suppressed powers following the evoked powers over the posterior scalp. The evoked powers above the 20 Hz band were not statistically significant, however, the gamma band was significantly evoked intra-individually; details in the gamma bands were varied among the subjects. Details of PSDs were complicated even for a simple task such as watching flashes; both synchronization and desynchronization occurred with different distributions and different time courses.

Electrogastrography (EGG) is the cutaneous recording of gastric myoelectrical activity, and the dominant frequency reflects the rhythm of the gastric slow wave. Ambulatory EGG is contaminated with a large amount of motion artifacts, and it is unclear how much of the signals comprising the dominant frequency originates from non-gastric sources. The aim of the present study was to evaluate the pattern of gastric and non-gastric signals in the dominant frequency histogram (DFH) obtained from long-term ambulatory EGG recordings. Ten normal controls and five post-gastrectomy patients participated in the present study. Twenty-four hour ambulatory EGG was recorded under normal daily conditions. The DFH of normal controls showed two distinctive peaks, and that of the post-gastrectomy patients, a single peak. The common peak at approximately 1.5 cpm was seen in both DFHs, and the peak at 3 cpm was seen only in the DFH of normal controls. Thus, the common peak was thought to be a product of non-gastric origin. In conclusion, the dominant frequency consists of gastric and non-gastric components which have a specific distribution pattern in the DFH. These findings quantified the contribution of gastric and non-gastric signals to the dominant frequencies in long-term ambulatory EGG.

Hemispheric dominance in contextual recognition is now under discussion. Auditory event-related potentials (ERPs) with a contextual decision task were recorded to study hemispheric dominance by using the wave energy and amplitudes of N400 for eight native volunteers. Two types of 80 sentences with four clauses were used as the structure: [subject] + [object or complement] + [object] + [two-syllable verb]. One type was congruent and the other deviated at the terminal clause as an incongruent sentence. Twenty-one channel ERPs were triggered at the verbs and recorded during -200 and 1,000 ms, with a noncephalic reference from 0.05 to 30 Hz. The wave energy was calculated as mean square potentials and was normalized with the background activity (pretrigger 200 ms). The amplitudes of N400 showed significant differences between the incongruent and congruent sentences, but the hemispheric dominance for the amplitudes of N400 was not significant between the incongruent and congruent sentences. Reaction times with the index finger to respond to the deviated verbs were 470.0 (mean) +/- 42.5 (SD) ms. The maximum normalized wave energy within the mean reaction time showed significant differences between the incongruent and congruent sentences, and the left hemispheric energy was shown to be significantly higher than the right one.

An attempt was made to apply functional magnetic resonance imaging (fMRI) to reveal cortical areas activated upon presentation of two groups of Chinese characters in six normal right-handed, male, Japanese subjects. Presentation of the characters representing 'abstract concepts' activated the bilateral occipital region without a significant difference between the bilateral occipital and temporal regions. Presentation of the characters representing 'concrete objects' resulted in significantly stronger activation in the left occipital and temporal regions. These results suggest that recognition of concrete characters involves a stronger initial process in the left occipital temporal cortices than recognition of abstract characters.

The aim of this study is to clarify the neurophysiological mechanism of cognitive impairments in migraine patients. We evaluated the relationships between event-related potentials (ERPs) and clinical parameters. Thirty-one migraine patients diagnosed by ICHD-II were submitted for this study. They were enrolled in headache-free periods. Clinical subtype (with/without aura), severity, duration, and preventative medicine use were evaluated as clinical parameters. We used 2 tones counting oddball paradigm to elicit P3 activities. EEG was recorded from 20 electrodes on the scalp according to international 10/20 system. We assessed the distribution of generator activity in the cortex by standardized low-resolution brain electromagnetic tomography (sLORETA). Regression analyzes of these clinical parameters and ERP source activities for the entire time frame was computed using sLORETA. sLORETA revealed a significant negative correlation in both attack frequency per a month and preventative medicine use in the cingulate gyrus and superior frontal gyrus 280 ms after the onset of target stimuli. Therefore, migraine patients might have impairment of cognitive function, such as executive dysfunction. The dysfunction is reflected by the attenuated activity of the frontal gyrus in sLORETA.

— In this paper, the relative influences of misalignment such as cross-talk, vertical shift, and motion blur on visual fatigue by using a binocular stereoscopic display has been verified. Experiments were conducted for two cases: a still image and a motion image. They were evaluated by using the simulator sickness questionnaire (SSQ). By changing the disparity angle, cross-talk, and vertical shift in the still-image experiment, it was found that the SSQ score of each parameter increased as the amount of each factor increased. With a two-sample t-test between the presence and absence of each factor, a significant difference was found for the case of a more than 36-arcmin disparity, more than 20% cross-talk, and more than 10% vertical shift. In the motion-image experiment, in which motion speed and the misalignment were varied, it was found that movement of the disparity angle caused much more visual fatigue in comparison with the misalignment factors, which were cross-talk and vertical shift. In contrast, motion images in addition to the cross-talk and/or vertical shift had a slight but unnoticeable relationship to an increase in visual fatigue. Therefore, it was concluded that vertical shift dominated the evaluation for still images, and the movement itself dominated the evaluation for motion images. The results suggest that it is necessary to evaluate visual fatigue according to the representing case, still or motion images, of a 3-D stereoscopic display.

Two infants, an 11-month-old boy and a 7-month-old girl, presented with subarachnoidal abscess associated with severe bacterial meningitis refractory to intensive managements with antibiotics. Computed tomography (CT) revealed bifrontal extracerebral low-density areas and remarkably enhanced surfaces of the bilateral frontal lobes postcontrast. Surgical exploration disclosed thick pus accumulation in the subarachnoid space which required curettage. The boy developed appropriately for his age, but the girl showed severe psychomotor retardation because of additional complications such as subdural fluid collection and hydrocephalus associated with the subarachnoidal abscess. Appropriate early neurosurgical management of subarachnoidal abscess is essential for satisfactory psychomotor development. Postcontrast CT should be performed to detect the subarachnoidal abscess as early as possible, and extensive craniotomy to remove the subarachnoidal pus accumulation performed to preserve psychomotor development.

Among the several methods of intraoperative facial nerve monitoring in acoustic neurinoma surgery, the evoked facial muscle responses (EFMR) by electrical stimulation of the nerve have been most commonly and effectively used [2, 4]. However, the most effective stimulus parameters during surgery have not yet been defined. In the past 9 years, monopolar low constant current stimulation (0.5–0.6 nA) was applied in 52 cases. We report intraoperative findings of the EFMR and their relations to postoperative facial functions.