The relationship between intestinal microbiota and cognitive function has been investigated as one of the major topics within the intestinal microbiota–gut–brain axis. Although an increasing number of studies have demonstrated an improvement in learning and memory when using probiotics or prebiotics, to date, there are no studies that target the cognitive flexibility observed in the early stages of several neuropsychiatric diseases, including dementia. We have recently developed a novel behavioral task using the touchscreen operant system to assess cognitive flexibility. We found that the disruption of the intestinal microbiota in mice induced a decline in cognitive flexibility. In the present study, we investigated the effects of treatments consisting of Bifidobacterium animalis subsp. lactis and arginine (Bifal + Arg), which promote the production of intestinal bacterial polyamine, on cognitive flexibility in the mouse model. Male C57BL6 mice orally treated with Bifal + Arg three times a week gradually decreased the 1st-choice incorrect diagonal rate with repeated reversals compared with the control group. Furthermore, in serial reversal phases, Bifal + Arg-treated mice shifted to the behavior of choosing a new correct spot more quickly after the reversal, and this was faster with repeated reversals. These results indicate that this treatment adapts to change and improves cognitive flexibility. This is the first report to show that intestinal environmental control, including probiotics and prebiotics, improves cognitive flexibility in mice.

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Bifidobacterium animalis subsp. lactis and arginine mixture intake improves cognitive flexibility in mice

In this paper, we investigate the validity of music as an authentication key. Recently, it is often necessary to use a personal authentication system when we would like to use web sites and personalized systems. We often need to memorize a password to use them. Although a long password is preferable from system side, it is not preferable from user side because it is hard to remember it. Although a short password is preferable from user side, it is not preferable from system side because it is easy to crack it. We aim to solve this problem by using music as a key for a personal authentication system. We verified the usefulness of music-based personal authentication through some experiments.

Evaluating the validity of music as an authentication key

Cognitive flexibility is the ability to rapidly adapt to a constantly changing environment. It is impaired by aging as well as in various neurological diseases, including dementia and mild cognitive impairment. In rodents, although many behavioral test protocols have been reported to assess learning and memory dysfunction, few protocols address cognitive flexibility. In this study, we developed a novel cognitive flexibility test protocol using touch screen operant system. This test comprises a behavioral sequencing task, in which mice are required to discriminate between the “rewarded” and “never-rewarded” spots and shuttle between the two distantly positioned rewarded spots, and serial reversals, in which the diagonal spatial patterns of rewarded and never-rewarded spots were reversely changed repetitively. Using this test protocol, we demonstrated that dysbiosis treated using streptomycin induces a decline in cognitive flexibility, including perseveration and persistence. The relative abundances of Firmicutes and Bacteroides were lower and higher, respectively, in the streptomycin-treated mice with less cognitive flexibility than in the control mice. This is the first report to directly show that intestinal microbiota affects cognitive flexibility.

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Impact of Intestinal Microbiota on Cognitive Flexibility by a Novel Touch Screen Operant System Task in Mice

This paper describes a concept of music-based personal authentication. In recent years we frequently need to use personal authentication system to use the Internet and so on. Password is a popular way for personal authentication. However, long password is not good for remembering, while short password is not good for protecting. In the proposed method, we pay attention to the feature of music and discuss the potential of music for personal authentication system.

A Proposal of Music-Based Personal Authentication System

Measuring the distance between words has many applications in natural language processing. By using the conceptual distance using the thesaurus dictionary, it is possible to obtain a distance scale different from the word similarity using the cosine similarity. However, the distance cannot be measured except for the words listed in the thesaurus dictionary. To solve the problem, this study aims to estimate the conceptual distance between unknown words using machine learning. Through some experiments, the conceptual distance of an unknown word could be estimated with the same level of accuracy as that of a known word.

Estimating the conceptual distance between unknown words using machine learning

In this study, we established a topic selection method that recommends topics that are interesting and unfamiliar to users. To achieve this aim, we used conceptual distance to identify topics that were unfamiliar to users and improved the accuracy of this method by removing conceptually similar words. Many words used in conversations are excluded in the dictionaries and thesauruses. Thus, we developed a model for conceptual distance measurement using machine learning to measure conceptual distances even for such words. By conducting the subject experiments, we confirmed that the established system recommends topics a user is interested in but unfamiliar with compared with the baseline method developed in a previous research. 

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Mitsuharu Matsumoto

Papers

Impact of Intestinal Microbiota on Cognitive Flexibility by a Novel Touch Screen Operant System Task in Mice

A Proposal of Music-Based Personal Authentication System

Estimating the conceptual distance between unknown words using machine learning

Topic Selection Using Conceptual Distance: How to Select Topics that are Interesting but Unfamiliar to Users