Bussey rat touchscreen chamber

General ApproachIn short, the rats were individually placed in LaborasTM cages for 48 h sessions at weeks 4, 6, 8, 10, and 12 of age to measure locomotor activity, eating, and drinking behavior. The operant behavior was assessed in touchscreen operant chambers (Bussey Rat Touchscreen Chamber, Campden Instruments, Loughborough, Leics, UK), whereby the pre-training and visual discrimination (VD) tests were performed during the adolescent period of the rat (~week 4 to 10 of age) and the motivational tests were performed during either adolescence or early adulthood, depending on the acquisition and performance speed during daily testing for each individual rat. The rats were tested twice a day for 30 min sessions, with a minimum interval of 3 h between sessions for all tests, except for the 60 min progressive ratio task, which was performed once per day. In the VD task, the rat is required to discriminate two images and touch the correct image in order to receive a reward pellet [25 (link),26 (link)]. This task measures learning by stimulus discrimination and long-term memory while assessing the performances over sessions across several days [25 (link)].

Touchscreen chambers equipped with a touchscreen, infrared beams, white house light, pellet dispenser, and a feeder magazine with magazine light were placed within a sound-attenuating chamber, fitted with a camera positioned above the operant chamber to monitor the rats (Bussey Rat Touchscreen Chamber, Campden Instruments, Loughborough, Leics, UK). To register responses, the operant chambers were equipped with infrared beams inside the feeder magazine and on the surface of the touchscreen. A black mask with two apertures was placed in front of the touchscreen to minimize unintended responses on the touchscreen and to guide the rat towards the correct locations on the screen. Presentation of the stimuli, reward delivery, and data collection were conducted using ABET II Touch Software (Campden Instruments, Loughborough, Leics, UK) and a multimedia research control Whisker system [28 (link)].