An implantable CMOS image sensor for monitoring deep brain activities of a freely moving mouse

We have developed CMOS based image sensing devices that can be implanted in a mouse deep brain to monitor the neural activities of a freely-moving mouse. Transgenic mice that express GFP (green fluorescence protein) in the midbrain DA (dopamine) neurons under the control of the rat TH (tyrosine hydroxylase) gene promoter, was used for the experiments. The fluorescence was measured through GFP which acts as the sensor for DA and successfully demonstrated that the implanted device can be used for monitoring the neural activities in long term. Also the next generation sensor which realizes more stable operation in the mouse brain is presented.