Automated system for training and assessing string-pulling behaviors in rodents

String-pulling tasks have been used for centuries to study coordinated bimanual motor behavior and problem solving. String pulling is rapidly learned, ethologically grounded, and has been applied to many species and disease conditions. Typically, training of string-pulling behaviors is achieved through manual shaping and baiting. Furthermore, behavioral assessment of reaching, grasping, and pulling is often performed through labor intensive manual video scoring. No system, to our knowledge, currently exists for the automated shaping and assessment of string-pulling behaviors. Here we describe the PANDA system (Pulling And Neural Data Analysis), an inexpensive hardware and software system that utilizes a continuous string loop connected to a rotary encoder, feeder, microcontroller, high-speed camera, and analysis software for assessment and training of string-pulling behaviors and synchronization with neural recording data. We demonstrate this system in unimplanted rats and rats implanted with electrodes in motor cortex and hippocampus and show how the PANDA system can be used to assess relationships between paw movements and single-unit and local-field activity. We also found that automating the shaping procedure significantly improved overall performance, with rats regularly pulling >100 meters during a 15-minute session. In conclusion, the PANDA system will be of general use to researchers investigating motor control, motivation, and motor disorders such as Parkinsons disease, Huntingtons disease, and stroke. It will also support the investigation of neural mechanisms involved in sensorimotor integration. HighlightsO_LIHigh-speed tracking of continuous grasping and pulling behaviors. C_LIO_LIAutomated and adaptive reinforcement of string-pulling behavior. C_LIO_LIIntegration with neural recording and video tracking systems. C_LIO_LIOpen-source software and hardware. C_LI Supplemental FilesThe supplemental pdf contains additional designs and behavioral data and has been uploaded. Source code and 3D and laser cut design files can be found at: https://github.com/CowenLab/String_Pulling_System/ Videos are in the GitHub repository at: https://github.com/CowenLab/String_Pulling_System/tree/main/Videos