and Brain Sciences
sakoyama [at] indiana.edu
- 1995 Ph.D., The University of Tokyo
Area of Study
- Biology, Behavior and Neuroscience
- Animal Behavior
- History of Animals in Human Culture
My study field is social neuroscience. I am interested in how social environment affect the physiological conditions and behaviors of individuals. Key parameters are pheromone and social status. I use mice in main but I am planning to expand toward human studies as well. In my studies so far, I found that social status affects the sperm activities in mice and that the difference diminishes when the vomeronasal organ is removed. This was a new finding in olfactory communication. I also found that female odors increase sperm density in male mice. This was also a new finding in olfactory communication. Currently, I am interested in the influence of pheromone on neurogenesis. In the past decades, it became accepted that neurogenesis continues until adulthood at the subventricular zone (SVZ) and at the dentate gyrus of the brain, in main. In females it was found that males' pheromones stimulate neurogenesis at SVZ and dentate gyrus. I am currently collaborating with chemists at the Department of Chemistry of IUB to identify the chemicals, which are involved in these phenomena.
Another project running now is related to the development of olfactory system and its relation to olfactory learning. Olfactory system starts to develop around embryonic day 11 in mice (pregnancy length is 19 days) and continues its development until postnatal days. During this development, the olfactory system goes through dramatic change especially around embryonic days 13 to 16. The development of olfactory system can be classified into early stage, changing stage and later stage with neurogenesis, apoptosis, and neurogenesis. The reason and function of this dramatic change is not known, which are the goals of my study.
As future studies on human, I hope to study how pheromone will affect mood, preference, and physiological conditions (like post-parturition depression (PPD), menopause symptom (MP), and premenstrual symptoms (PMS). Identification of chemicals, which will ease these symptoms, is the primary goal of my future plan.
List of some of my "First"s:
1) New finding: sperm activity is different depending on social status in mice.
2) New finding: sperm density increase when mice are exposed to females' odor.
3) My book on the history of keeping birds in Japan is the first book on the history of keeping birds in Japan and received more than 10 reviews on journals and newspapers.
4) I have the record of first successfully breeding a wild mice species, Japanese long-tailed field mice, Apodemus argenteus. (Call me a mice whisperer!)
5) In collaboration with P-tech, Co. (Osaka, Japan), I made a microscope with built-in thermo plate, which can be used using car battery for studies of sperm in the field. (Please let me know if you are interested in using)
I have mentored more than 50 students in Japan to design and conduct researches and write papers. I, myself, was a "pure" behavior person studying developmental/comparative psychology and animal behavior/ethology until I received my Ph.D., and, since then, I have been studying biophysic/cell biology of sperm cells, chemical engineering of microfluidics, and neuroscience of the neurogenesis at SVZ. I know there are very few people who know these diverse study fields well and I hope to be a bridge between behavior and cell biology in teaching.
Chemical component attractant for mice: Patent application number: JA03046, Japan
Koyama, S. 2010 Encyclopedic Dictionary of Biology. Ishikawa, O. et al., eds. Tokyokagakudozin, Inc., Tokyo. In charge of columns related to "olfactory communication": "Vandenbergh effect", "Dormitory effect", "pheromone", "Bruce effect", "Whitten effect", "Lee-Boot effect", "primer effect", "releaser effect", etc. (in Japanese).
Koyama, S. 2010 Establishment and management of individual relationships: pair-bonding and social play behaviors. In Yasuhiko Kondo et al. eds Behavioral Neuroendocrinnology. Nishimura-shoten, Tokyo, Japan (in Japanese).
Soini, H.A., Wiesler, D., Koyama, S., Féron, C., Baudoin, C., Novotny, MV. 2009 Comparison of uinary scents of two related mouse species, Mus spicilegus and Mus domesticus. Journal of Chemical Ecology, 35 (5), 580-589.
Koyama, S. 2008. Ethology of Olfactory Communication in Animals. Fragrance Journal Inc., Tokyo, Japan (in Japanese).
Novotny, MV, Soini, HA, Koyama, S., Wiesler, D., Bruce, KE, Penn, DJ. 2007 Chemical identification of MHC-influenced 4 volatile compounds in mouse urine. I: Quantitative 5 proportions of major chemosignals. Journal of Chemical Ecology, 33, 417-434.
Koyama, S. 2007 History of keeping small birds and bird song contests in Japan. In The Association of Japanese University Presses ed. The Time of Natural History. The Association of Japanese University Presses, Tokyo, Japan, pp.42-44 (in Japanese).
Koyama, S. 2007 Mechanisms of olfactory communication in rodents. In Tatsuaki Shibuya, Masumi Ichikawa eds The science of smells and odors. Asakura Shoten, Shinjuku, Japan, pp. 210-216 (in Japanese).
Koyama, S., Amarie, D., Soini, H.A., Novotny, M.V., Jacobson, S.C. 2006 Chemotaxis assays of mouse sperm on microfluidic devices. Analytical Chemistry, 78, 3354-3359.
Koyama, S. & Kamimura, S. 2005, Soiled bedding from group-housed females exerts strong influence on male reproductive condition. In: R.T. Mason, M.P. LeMaster, and D.Müller-Schwarze eds, Chemical Signals in Vertebrates. Kluwer Academic/ Plenum Publishers, New York, pp. 168-172.
Koyama, S. 2004 Primer effects by conspecific odors in house mice: a new perspective in the study of primer effects on reproductive activities. Hormones and Behavior, 46, 303-310.
Aikawa, H., Koyama, S., Matsuda, M., Nakahashi, K., Akazome, Y., Mori, T. 2004 Relief effect of vitamin A on the decreased motility of sperm and the increased incidence of malformed sperm in mice exposed neonatally to Bisphenol A. Cell and Tissue Research,.315, 119-124
Koyama, S. & Kamimura, S. 2003 Effects of vomeronasal organ removal on the sperm motility in male mice. Zoological Science, 20, 1355-1358.
Koyama, S. & Kamimura, S. 2003 Study on the developmental changes, variance of sperm motility, and social dominance of male mice. Physiology and Behavior, 80, 267-272.
Koyama, S. 2003 The history of tricks using varied tits and the image of animals. In: Japanese Society for Applied Animal Behavior ed. Dawn of Applied Animal Behavior Science in Japan. Japanese Society for Applied Animal Behavior, Utsunomiya, Japan, pp. 261-265. (in Japanese)
Koyama, S. & Kamimura, S. 2001, Effects of social dominance and female odor on sperm activity of male mice. In: A. Marchlewska-Koj, J.J.Lepri, and D.Muller-Schwarze eds, Chemical Signals in Vertebrates. Kluwer Academic/ Plenum Publishers, New York, pp. 403-410.
Koyama, S. & Kamimura, S. 2000 Influence of social dominance and female odor on the sperm activity of male mice. Physiology and Behavior, 71, 415-422.
Koyama, S. 1999 The History and Mechanism of Tricks using varied tits in Japan. Housei University Press, Tokyo (in Japanese).
Koyama, S. & Kamimura, S. 1999 Lowered sperm motility in mice of subordinate social status. Physiology and Behavior, 65, 665-669.
Koyama, S. 1998 Social dominance and play behavior in Japanese monkeys. In: N. Itoigawa & T. Minami eds. Ethological studies on monkeys and human. Baifukan, Tokyo. pp.71-83 (in Japanese).
Koyama, S. 1995 Reproductive activity of Apodemus argenteus under laboratory condition. The Journal of the Mammalogical Society of Japan, 20, 117-124.
Koyama, S. 1995 Differential response to the odor of familiar intruder mice in male mice (Mus musculus). Journal of Ethology, 13, 47-56.
Koyama, S. 1995 The differential responses to the odor of unfamiliar male conspecifics in dominant, subordinate, and isolated mice. Journal of Ethology, 13, 165-173.
Koyama, S. 1995 Effects of a short period of isolation in adulthood on the aggressive behavior of dominant and subordinate male mice. Journal of Ethology, 13, 175-180.
Koyama, S. 1994 On the Growth and development of Apodemus argenteus under laboratory conditions. Honyurui Kagaku (Mammalian Science), 33, 109-122 (in Japanese with English abstract).
Koyama, S. 1993 Isolation effect in mice (Mus musculus): (i) does it really induce aggression? Journal of Ethology, 11, 117-130.