Implantable Microimaging Device for Observing Brain Activities of Rodents

In this review, we present an implantable microimaging device to observe brain activities of small experimental animals such as mice and rats. Three categories of such devices are described: an optical fiber system, a head-mountable fluorescent microscope, and an ultrasmall image sensor that can be directly implanted into the brain. Among them, we focus on the third one, because this is a powerful tool to explore brain activities in deep brain region in a freely moving mouse. The device structure and performance are shown with some examples of deep brain images of mice.