Schematic overview of the Rodent Big Brother (Home Cage Analyzer; ActualHCA™) system.

<p>Rats are housed in social groups in standard IVC cages with the Home Cage Analyzer equipment slotted inside an adjacent cage void. The sealed baseplate RFID reader derives positional and temperature information for each animal individually from their subcutaneous RFID chip. The infrared HD video camera captures 25 fps, infrared gray scale video, continuously. An array of infrared LEDs above the cage provides even illumination day and night. The IVC home cage sits immediately above a baseplate RFID reader. The mini-computer captures the video and baseplate data. The system enables manual behavioral analysis at any time of day or night, overall motion detection (whole-cage activity) for the group of rats, and automated detection of ambulatory and vertical activity, and subcutaneous temperature. Representative 7-day readouts are shown for ambulatory activity and subcutaneous temperature; the 12 h light-dark cycle is indicated by white-gray shading.