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A surplus of unused parts of vegetables (e.g., white cabbage [cabbage] cores and outer leaves) is generated daily by factories of fresh-cut vegetables. These parts are difficult to effectively utilize and are often discarded as biodegradable industrial waste. This study aimed to develop an efficient method for producing l-ornithine from cabbage residues. First, we added protease (Sumizyme FP) to the cores and outer leaves of sterile cabbages. After 8 days, the amount of l-arginine released was approximately fivefold the amount in the initial content. As l-arginine is a precursor of l-ornithine, the addition of protease combined with Pediococcus pentosaceus produced l-ornithine. However, the rapid lactic acid fermentation suppressed the metabolism of l-arginine to l-ornithine, which we overcame by adjusting the pH by adding eggshell. The anaerobic fermentation of the cores and outer leaves of sterile cabbages with 5% eggshell for 8 days produced 184 ± 2 μmol of l-ornithine/100 g cabbage. PRACTICAL APPLICATIONS: This level of l-ornithine production is higher than that observed in freshwater clams (81-116 μmol/100 g), which are considered to be high in l-ornithine. This method can be applied to the production of inexpensive and safe l-ornithine-containing food materials derived from vegetables. Furthermore, ingestions of vegetables fermented by this method would provide a variety of health benefits of l-ornithine. The widespread adoption of this method will not only reduce the amount of waste generated daily from fresh-cut vegetable factories, but will also enable upcycling as a higher value-added food material.

While abnormalities in monoamine metabolism have been investigated heavily per potential roles in the mechanisms of depression, the contribution of amino acid metabolism in the brain remains not well understood. In additional, roles of the hypothalamus-pituitary-adrenal axis in stress-regulation mechanisms have been of much focus, while the contribution of central amino acid metabolism to these mechanisms has not been well appreciated. Therefore, whether depression-like states affect amino acid metabolism and their potential roles on stress-regulatory mechanisms were investigated by comparing Wistar Kyoto rats, which display depression-like behaviors and stress vulnerability, to control Wistar rats. Brain amino acid metabolism in Wistar Kyoto rats was greatly different from normal Wistar rats, with special reference to lower cystathionine and serine levels. In addition, Wistar Kyoto rats demonstrated abnormality in dopamine metabolism compared with Wistar rats. In the case of stress response, amino acid levels having a sedative and/or hypnotic effect were constant in the brain of Wistar Kyoto rats, though these amino acid levels were reduced in Wistar rats under a stressful condition. These results suggest that the abnormal amino acid metabolism may induce depression-like behaviors and stress vulnerability in Wistar Kyoto rats. Therefore, we hypothesized that abnormalities in amino acid and monoamine metabolism may induce depression, and amino acid metabolism in the brain may be related to stress vulnerability.

In a previous study, we confirmed that orally administered L-ornithine can be transported into the brain of mice. In addition, orally administered L-ornithine, within a limited dose range, had an anxiolytic-like effect in the elevated plus-maze test. However, the mechanism by which orally administered L-ornithine reduced the stress response in mice is still unclear. Experiment 1 determined whether orally administered L-ornithine could reduce the stress-induced activation of hypothalamic-pituitary-adrenal axis. Mice were orally administered L-ornithine (0, 0.75, 1.5 and 3 mmol/10 ml/kg, p.o.), and restrained for 30 min from 30 min post administration. There was a significant decrease in the corticosterone levels in the group receiving 0.75 mmol of L-ornithine compared to the control group. In Experiment 2, the effect of orally administered L-ornithine (0 and 0.75 mmol/10 ml/kg, p.o.) on endogenous monoamine release was investigated using in vivo microdialysis. Only the monoamines metabolites 5-hydroxyindoleacetic acid (5-HIAA), dihydroxyphenylacetic acid (DOPAC) and homovallinic acids (HVA) were detected in the present study. Dialysate concentrations of 5-HIAA, DOPAC and HVA were not significantly changed immediately after administration of L-ornithine and restraint stress. In conclusion, changes of corticosterone concentrations by orally administered L-ornithine were not related to alterations in brain monoamine metabolisms.

I.c.v. injection of L-ornithine has been shown to have sedative and hypnotic effects on neonatal chicks exposed to acute stressful conditions. To clarify the mechanism, we conducted three experiments under strengthened stressful conditions with corticotropin-releasing factor (CRF). In Experiment 1, the effect of i.c.v. injection of CRF, L-ornithine (0.5 μmol) or CRF with L-ornithine on the stressful response of chicks was investigated. Compared with the vehicle control, CRF increased distress vocalizations and the time spent in active wakefulness. L-Ornithine increased the time spent in sleeping posture, even following stimulation with CRF. In Experiment 2, dose-dependent effects of L-ornithine were investigated using i.c.v. administration with vehicle, CRF alone or CRF plus L-ornithine (0.125, 0.25 or 0.5 μmol). L-Ornithine decreased the CRF-stimulated distress vocalizations in a dose-dependent manner. In Experiment 3, the chicks were injected i.c.v. with either CRF, CRF plus L-ornithine (0.5 μmol), CRF plus the Y-aminobutyric acid (GABA)_A receptor antagonist picrotoxin or L-ornithine with picrotoxin. The sedative and hypnotic effects induced by L-ornithine were blocked with co-administration of picrotoxin. These results suggest that L-ornithine could attenuate CRF-stimulated stress behaviors acting at GABA_A receptors.

これまで神経場のダイナミクスに関する研究が数多くされてきた．特に，局在興奮をもつ神経場は自己組織化マップ（SOM，Self-Organizing Map）のアルゴリズムの基礎をなしている．そこで我々は神経振動子場に着目し，局在振動をもつ３層の神経振動子場のモデルを提案する．２つのメキシカンハット型層内結合をもつ神経振動子場は１つないし２つ以上の局在振動を外部入力の複数の極大付近に安定して保持し，また各局在振動内では同位相に，そして異なる局在振動間では位相差を最大にするように位相を引き込むことがわかった．この神経振動子場は，情報分離に伴う結び付け問題を解く振動子型SOMの構成要素になりうる．

Elderly people tend to perceive color as more yellowish than younger people do, and their ability to discriminate between blueish colors deteriorates as they grow older. This paper describes measurements of visual chromatic spatial and temporal frequency responses in subjects aged 60 to 75 years old to gain a better understanding of age-related changes in color perception and to clarify some differences between young and elderly people. We found that visual chromatic spatial and temporal frequency responses to ayellow-blue (dominant wavelength : 565-445 nm) stimulus were significantly reduced in comparison with those to a red-green (495 nm and its conjugate) stimulus. The results suggest that weakened optical functions in the eye and in the power to send visual signals from the retina to the nervous system are likely causes of this deterioration of color -contrast sensitivity.

Self-organizing continuously-overlapping map is shown to have ability to detect the first and second nonlinear principal components. This is an extended version of the self-organizing overlapping mapping. The model was applied to FFT data of sound, and some others. These data are characterized by a combination of two kinds of features, such as the pitch and the quality of tone. The model has two self-organizing layers. One layer extracts and maps continuously one feature, and the other layer does the same with respect to the other feature. The ability of generalization depending on data structure is demonstrated. Comparison to Kohonen's SOM is also discussed.

A neural network for function approximation is treated theoretically. The structure and the information processing of this network is similar to those of the forward-only counterpropagation network, while the learning rule is improved. That is, the learning rule of the hidden layer is self-organizing map instead of winner-take-all. For the case that a target function and the network are with one input and one output, parameters of the learning rule are lead theoretically to obtain the function approximation with the least square error, and the theoretical results are verified by computer simulations.

Dynamic link architecture is self-organizing map applied to image recognition. Mapping formed from data image to sample image. It tends to link two points which have similar local features, and so, can be distorted to some extent. Similarity of two images is evaluated after transforming data image by the mapping. Thus, dynamic link architecture is tolerant to distortion or rotation of data images. We propose a mathematically tractable model of dynamic link architecture, and reduced it to simple phase dynamics, which clearly shows how the model restores rotated data images. Computer simulations verify the theory.

Pattern recognition invariant against deformation or translation can be performed with dynamic link architecture, which has been proposed by von der Malsburg. Dynamic link is applied to many engineering examples efficiently, but has not been analyzed mathematically. We propose a mathematically tractable model of dynamic link architecture. Our model matches common parts between a template image and a data image. To analyze model mathematically, we derive the phase dynamics from the model equation. We also carry out a computer simulation to verify the mathematical theory.

We first present a mathematical analysis of the relation between the parameters and the behavior of the basic module in the proposed neural network model for visual motion detection. Based on the analytical results, a learning rule is put forth that can develop velocity selectivity of directionally selective cells in the basic module. The learning rule is furthermore introduced into the total model called a 'mass model', which is constructed with many basic modules. Numerical simulation results showed that each basic module in the mass model learned in a self-organizing manner to acquire selectivity for the velocity of an input stimulus. The proposed learning rule would be plausible in the actual nervous system in that it is simple and can be described with only local information.

In the brain of neonatal chicks, tryptophan has a sedative effect, and a part of this effect might be dependent upon its metabolite, serotonin. However, the functional mechanisms have not been fully clarified, since l-tryptophan produces kynurenic acid (KYNA) through the kynurenine pathway. The present study aimed to clarify the effect of KYNA on the stress response upon social isolation. Intracerebroventricular injection of KYNA induced a strong sedative effect under stress compared with the effect of l-tryptophan, with or without intracerebroventricular injection of corticotrophin-releasing hormone (CRH). KYNA dose-dependently induced sedative and hypnotic effects under CRH-augmented social isolation stress. Taken together, these results indicate that KYNA is a likely candidate for the sedative and hypnotic effects of tryptophan under acutely stressful conditions.

In this paper, we investigate the effect of synaptogenesis on memories in the brain, using the abstract-associative memory model, Hopfield model with the zero-order synaptic decay. Using the numerical simulation, we demonstrate the possibility that synaptogenesis plays a role in maintaining recent memories embedded in the network while avoiding overloading. For the network consisting of 1000 units, it turned out that the minimum decay rate to avoid overloading is 0.02, and the optimal decay rate to maximize the storage capacity is 0.08. We also show that the average numbers of replacement synapses at each learning step corresponding to these two values are 1187 and 21024, respectively.