A micro imaging device for measuring neural actvities in the mouse deep brain with minimal invasiveness

This paper describes a micro imaging device that is implantable in a mouse deep brain with minimal invasiveness to measure neural activities through fluorescence. The device consists of a dedicated micro CMOS image sensor and LEDs to excite fluorophore on a flexible substrate. To minimize invasiveness when it is implanted into a mouse brain deeply, the size of the present device is much smaller than the previously developed one. The CMOS image sensor has pixels of 90 × 30 with the pixel size of 7.5 μm × 7.5 μm, and is coated on the top of the sensing area with color filter to cut off excitation light and to transmit only fluorescence. The width and the thickness of the device head is about 0.5 mm and 0.2 mm, respectively. Fundamental device characteristics and some experimental results using a mouse are demonstrated.