Bpod State Machine r2+ is an electronic system for precise measurement of small animal behavior. It measures the instant when discrete events happen (a snout enters a port, a tongue breaks a photogate, etc). The state machine can react to events by rapidly changing aspects of the environment, providing an excellent low-latency link between behavioral events, stimuli and reinforcement. Bpod is most often used for the 2AFC (two alternative forced choice) behavioral paradigm, but has been adapted to power a diverse range of behavioral assays (e.g. conditioned place preference, go / no-go, self-stimulation, social value measurement and others).
State machine r2+ can interface with up to 5 behavior ports (a.k.a. Nosepokes). Each behavior port contains one infrared photogate to detect port entry, one visible LED with software-adjustable intensity, and one solenoid valve for dispensing precisely measured liquid rewards through a steel drinking tube. The state machine has onboard digital inputs and outputs for triggering and synchronization with neural data acquisition systems. Beyond its onboard channels, the state machine can interface with external microcontroller boards via the Bpod Arduino, Teensy and Raspberry Pi shields. Bpod Modules leverage external microcontrollers to add capabilities like analog I/O, audio, quadrature encoders and motor control.
Please be advised that Bpod is a flexible behavior platform, and is not guaranteed to do everything you have in mind out of the box. It has a learning curve, and will require some programming to develop a behavioral protocol. Documentation and information about getting started is available on the Bpod wiki. Individual support is available in the Bpod forums. A central focus of our company is to grow the current community of Bpod users, to optimize the system for ease of use, and to add to its capabilities.
State Machine r2+ features several hardware improvements over r2:
- Processing Speed: An ARM Cortex M7 processor @ 600MHz, up from Cortex M4 @ 180MHz
- USB Bandwidth: High Speed USB2 (up to 480Mbit/s), up from Full Speed (up to 12Mbit/s)
- More onboard I/O:
- One additional behavior port (5 total)
- Flex I/O channels (4 total) are a new type of channel that can be configured in user code as digital out, digital in, analog out or analog in (both analog modes are 0-5V range, 12bit)
- Memory: An 8MB PSRAM IC enables improved sampling and logic operations
- Efficiency: A more efficient isolation scheme reduces the state machine's power draw for improved performance
- Enclosure: A premium enclosure provides improved mechanical robustness
