C6 Novel behavioural readouts of the bachd rat in the reeperbahn and barnes maze tests

Background Huntington’s disease (HD) is an inherited, autosomal, neurodegenerative disease. Symptoms of HD patients often include motor, emotional and cognitive deficits. BACHD rats overexpress the full length human mutant huntingtin gene with 97 alternating CAA/CAG repeats under control of the human HD promoter and are considered to be a valid option to gather novel insights on behavioural level. Aims We investigated wild type and transgenic male rats, with 7–15 months of age, for possible cognitive, social and motor impairments by performing the Reeperbahn test and Barnes maze. Methods/technique In the Reeperbahn test male rats had to learn the location of a sexually active wild type female in a dry-land apparatus. Males could freely explore the arena during learning/reversal learning, whereas in the recall sessions the female was removed. Additionally to automated behaviour measurements, the ultrasound vocalisation of males was recorded. The Barnes maze test investigates the possible spatial learning/reversal learning deficits in BACHD rats. The animals were challenged to use either proximal (egocentric) or distal (allocentric) visual cues to locate and remember the target zone. Results/outcome The Reeperbahn test data show that BACHD rats have a decreased exploration time when the female’s location is reversed. Furthermore, BACHD rats exhibit a deficit in reversal learning as well as decreased locomotor activity. Ultrasonic vocalisations and Barnes maze data are currently analysed. Conclusions All together, these newly established behavioural tests provide further evidence of cognitive and motor deficits in BACHD rats.