Miniature Implantable Systems For Optical Neural Control And High Sensitive Free-moving Animal Behavior Recording

Ethology plays an essential role in examining the animal's behavior patterns and motion attitudes,it's a reflection of the physiological and mental state.For the experimenters,monitoring the behaviors of animals throughout the experiment is always should be taken into consideration.Appropriate monitoring method can detect the specific behavior patterns and furtherly demonstrates the relations between the exterior stimulation and interior mechanism.Currently,the most widely used technique for animal behavior monitoring is that: based on video recording and digital imaging processing,selecting a region or whole animal body as the target,and tracking it to get the trajectory which can be used to generate the location or speed heatmaps to reflect the behavior patterns during the experiment.For further analyzing,pattern recognition algorithms(e.g.,Support Vector Machine et.al)can automatically detect specific behaviors.It can't be denied that video-recording-based monitoring works well in most cases,however,the limitations shouldn't be ignored.Firstly,since the big volume of video data restricts the frame rate,some fine behavior within milliseconds is hard to capture.Secondly,it's hard to target to the animal when entering the closed area or environment light in poor condition.Optogenetics provides a high spatial and temporal resolution method for neural circuit modulation,which allows experimenters precisely manipulate the neurons in millisecond-scale.The combination of optogenetics and behavior monitoring can be used to study the reflection between specific neural circuit and function,which involves two aspects of neuroscience.Based on above background,this article proposes and implements a miniature implantable system for optical neural control and high sensitive free-moving animal behavior recording.The system including two parts: hardware and software.For hardware,3-axis acceleration and 3-axis angle rate are acquired by a MEMS(Micro-Electro-Mechanical System)inertial sensor;A BLE(Bluetooth Low Energy)So C(System-on-a-Chip)is applied for wireless data communication and controlling an implantable optic-coupled LED probe.For software,we developed an UI(Users Interface)software based on C# program language,which involves 3 functions: receiving and decoding data,motion waves displaying,optogenetics parameters controlling.The size of hardware is about 14.5×17.5×8mm,3.1 gram,it can be mounted on mouse head without any cable and fiber.In some animal experiment paradigm,for instance,when study animal innate fear,by presenting an expanding dark disc known as a looming stimulus,such a system can be used to detected the induced freeze or flight behaviors.