Because of the reorganization of our laboratory, which was carried out by our institute, and due to the separation of the vivarium and a group of biologists with vivarium personnel from our laboratory into a separate structural unit of the Experimental and clinical research department, we are closing our scientific direction on the study of the biological danger of nanoparticles and their effect on the brain and behavior of animals. We have been studying this problem for about 15 years and have obtained a rich, good and substantiated scientific result, which is summarized in our latest publications and reviews on this topic. In the nearest future, by the end of the year, this result will be presented in detail and in the form of a generalized analysis in the relevant section of our website. We do not see the point in conducting further research in this direction, because the briefly formulated our main result and conclusion from the research is as follows: The more toxic the material of the nanoparticles, in itself, the more toxic these nanoparticles, that was to be expected. Nanoparticles made of inert metals (silver, gold) are the least toxic. In the amounts of oral consumption that can be realistically imagined in everyday life and / or at work, casual consumption, or even one-time intentional, the effect of nanoparticles exposure on the brain and cognitive abilities of a healthy adult is minimal, if not absent at all. The effect is slightly more pronounced in offspring and in aged individuals. However, in all cases, any peculiarities of the effect of nanoparticles on the brain and behavior in comparison with other toxic agents, especially special potent substances (opiates, etc.), should not be expected. Thus, from a scientific point of view, the problem loses its intrigue. We have not studied the effect on animals with various diseases. This problem is of even less interest to us, because it is more medical than physical problem. Therefore, we close the direction.