A joint research team of Osaka University and Tohoku University both in Japan develop the robotic microscope OSACaBeN that tracks an animal and measures the brain in real time.
Image: Nematode (from Osaka University Homepage)
A small animal such as a nematode that is moving is quickly tracked and placed in the field of view of a microscope. In addition, actions of neural cells are individually measured and stimulated based on the theory of a projection mapping system that projects beams having different wavelengths to predetermined regions. This robotic microscope was named OSACaBeN that stands for Optogenetic Stimulation Associated with Calcium imaging for Behaving Nematode. The research team was led by Associate Professor Koichiro Kimura, Department of Biological Sciences, Graduate School of Science, Osaka University, and Professor Koichi Hashimoto, Department of Information Science, Graduate School of Science, Tohoku University. The research team experimented model animals that are nematodes "C. elegance" with this microscope and found that the neural cells that secrete neural transmitter dopamine associated with emotion, desire, action, and so forth have different functions. The study was published in British Scientific Journal "Scientific Reports," which is a sister journal of "Nature."
In the robotic microscope, an electric positioning stage is moved at increments of 1/200 seconds so that a target animal such as a nematode or zebrafish is horizontally movable and it is always placed in the field of view of a mounted camera. Beams having different wavelengths with which an LCD projector is irradiated have been correlated with the cells of the animal. As a result, adjacent cells are irradiated with beams having different wavelengths in an accuracy of 1/100 mm or higher so that neural activities of the cells are measured and the cells are stimulated.
Nematodes are known as an experimental animal that is as small as around 1 mm in length and that is used to research the fundamental mechanism of the human brain. The research team experimented nematodes with the robotic microscope so as to solve a problem of the neuroscience about whether neural cells that secrete dopamine have individual functions. The experimental result revealed that the nematode has four neural cells that secrete dopamine at head and tail portions and that although these neural cells are similar in shape, only one neural cell at the dorsal head portion continuously responds to food (colon bacilli). In addition, the experimental result reveled that when the neural cell was shot and stimulated by a beam emitted from the projection mapping, the neural cell changed as it acted with food.
"We will use the robotic microscope for other model animals so as to clarify the relationship between brain activities and physical activities," said Associate Professor Kimura.
The head portion of the nematode is pictured with irradiation of infrared ray emitted from a bottom portion of the microscope. The head portion of the nematode is pictured 200 times per second. Whenever the head portion is pictured, the electric positioning stage is moved so that the head portion is placed at the center of the field of view of the lens. When dopamine secreting cells are observed and experimented, red fluorescent protein is recognized so as to secure the positions of the cells. The neural cells are irradiated with blue light emitted from the LCD projector so as to active them.