High-speed fluorescence imaging system for freely moving animals

An image sensor to be used in a miniature microscope system for recording brain activity over a wide cortical area (4-9 mm²) is presented. The image sensor is a 32 times 32 pixel array fabricated in bulk CMOS process. Each pixel has a 74 mum times 34 mum photodiode. The SNR performance of the image sensor is comparable to current state-of-the-art voltage-sensitive dye imaging sensors. The power consumption and weight of the proposed microscope is much lower than other voltage-sensitive dye imaging systems and can be used on awake and freely moving animals.