Ayato Tagawa

Development of Complementary Metal Oxide Semiconductor Imaging Devices for Detecting Green Fluorescent Protein in the Deep Brain of a Freely Moving Mouse

We have developed to observe neural activities in the deep brain of a freely moving mouse with green fluorescent protein (GFP). We implanted a dedicated complementary metal oxide semiconductor (CMOS) imaging device into the hippocampus or the basal ganglion of an anesthetized mouse to confirm the effectiveness of the CMOS imaging device for the detection of GFP generated in the deep brain of the anesthetized mouse. Moreover, we conducted an experiment to demonstrate the capability of the CMOS imaging device to detect GFP in the deep brain of a freely-moving mouse. As a result of the in vivo experiments with two methods of GFP expression, we successfully detected the light intensity of GFP in the hippocampus or the basal ganglion of the anesthetized mouse. Furthermore, we demonstrated that the implanted CMOS imaging device operated well in the freely moving mouse after one week from implantation. We demonstrated the basic technology to realize the observation of neural activities in the deep brain of a freely moving mouse.

Potentiometric Dye Imaging for Pheochromocytoma and Cortical Neurons with a Novel Measurement System Using an Integrated Complementary Metal–Oxide–Semiconductor Imaging Device

The combination of optical imaging with voltage-sensitive dyes is a powerful tool for studying the spatiotemporal patterns of neural activity and understanding the neural networks of the brain. To visualize the potential status of multiple neurons simultaneously using a compact instrument with high density and a wide range, we present a novel measurement system using an implantable biomedical photonic LSI device with a red absorptive light filter for voltage-sensitive dye imaging (BpLSI-red). The BpLSI-red was developed for sensing fluorescence by the on-chip LSI, which was designed by using complementary metal–oxide–semiconductor (CMOS) technology. A micro-electro-mechanical system (MEMS) microfabrication technique was used to postprocess the CMOS sensor chip; light-emitting diodes (LEDs) were integrated for illumination and to enable long-term cell culture. Using the device, we succeeded in visualizing the membrane potential of 2000–3000 cells and the process of depolarization of pheochromocytoma cells (PC12 cells) and mouse cerebral cortical neurons in a primary culture with cellular resolution. Therefore, our measurement application enables the detection of multiple neural activities simultaneously.

Multimodal Complementary Metal–Oxide–Semiconductor Sensor Device for Imaging of Fluorescence and Electrical Potential in Deep Brain of Mouse

We have developed a multimodal complementary metal–oxide–semiconductor (CMOS) sensor device for observing neural activities in the deep brain of a mouse. The CMOS sensor includes an image sensor, electrodes, and a light-emitting diode (LED). The image sensor was designed to be operated using only four inputs/outputs (I/Os) to reduce the number of connecting wires. The electrodes were placed on the pixel array of the sensor. Windows were opened in the electrode over the photodiodes to enable the fluorescence to be imaged using the pixels under the electrodes. An LED was mounted on the chip. The sensor chip was shaped like a shank to facilitate smooth insertion into the brain tissue. The entire device was coated with a parylene layer to make it biocompatible. The experimental results showed that the green fluorescent beads on the pixel array were successfully imaged using the LED on the chip as a light source. In a brain phantom, the change in the electrical potential was successfully sensed by the electrode, and green fluorescent beads were simultaneously imaged using the pixels under the electrode. We also demonstrated that the CMOS sensor device could successfully operate in the hippocampal area of an anesthetized mouse.

Complementary Metal Oxide Semiconductor Based Multimodal Sensor for In vivo Brain Function Imaging with a Function for Simultaneous Cell Stimulation

We have developed a multimodal complementary metal oxide semiconductor (CMOS) sensor device embedded with Au electrodes for fluorescent imaging and cell stimulation in the deep brain of mice. The Au electrodes were placed on the pixel array of the image sensor. Windows over the photodiodes were opened in the electrode area for simultaneous fluorescent imaging and cell stimulation in the same area of the brain tissue. The sensor chip was shaped like a shank and was packaged by two packaging methods for high strength or minimal invasion. The experimental results showed that the 90 ×90 µm2 Au electrodes with windows were capable of injecting theta burst stimulation (TBS)-like current pulses at 0.2–1 mA in a saline solution. We successfully demonstrated that fluorescent imaging and TBS-like current injection can be simultaneously performed in the electrode area of a brain phantom.

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.

Micro CMOS image sensor for multi-area imaging

We propose a micro complementary-metal-oxide semiconductor (CMOS) image sensor for simultaneous multi-area imaging. The sensor is designed for observation of mouse brain and its dimension is 550 µm × 850 µm. By connecting the sensors one after another, all the sensors are operated with only 5 lines. We demonstrate multi area imaging with a two sensor system as a preliminary experiment.

A multimodal sensing device for fluorescence imaging and electrical potential measurement of neural activities in a mouse deep brain

We have developed a multimodal CMOS sensing device to detect fluorescence image and electrical potential for neural activities in a mouse deep brain. The device consists of CMOS image sensor with on-chip electrodes and excitation light sources, all of which are integrated on a polyimide substrate. The novel feature of this device is its embedded on-chip electrodes which are partially transmit incident light so that the whole image can be acquired by the sensor. We have demonstrated the CMOS sensor device successfully operates in hippocampus area of an anesthetized mouse.

A CMOS sensor for in-vivo fluorescence and electrical imaging in a mouse brain

We report a complementary-metal-oxide-semiconductor (CMOS) image sensor for in-vivo imaging. The sensor is implemented on a flexible substrate with LEDs as excitation light sources. The images are successfully obtained in a mouse brain. We demonstrate a image contrast improvement method on the basis of image processing and multiple readout in order to overcome non uniform illumination of the excitation light.

A Multimodal CMOS Sensor Device with an On-Chip Mounted LED and Electrodes for Imaging of Fluorescence and Electrical Potential in a Mouse Deep Brain

Graduate School of Materials Science, Graduate School of Biological Sciences, Nara Institute of Science and Technology JST, CREST 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan, Phone: +81-743-72-6051, E-mail: ohta@ms.naist.jp

Real-time in vivo molecular quantification for freely-moving mouse's hippocampus

P3-f20 Voxel-based morphometry of the relationships between Intelligence Quotient and brain gray matter volume in 156 healthy Japanese children Michiko Asano1, Yasuyuki Taki1, Hiroshi Hashizume1, Yuko Sassa1, Hikaru Takeuchi1, Kohei Asano1, Mijin Lee1, Ryuta Kawashima1,2 1 Division of Developmental Cognitive Neuroscience, IDAC, Tohoku University, Japan; 2 Department of Functional Brain Imaging, IDAC, Tohoku University, Japan