Mouse behavioral experiments
The generation and characterization of the Hdh140Q knock-in mice have
been previously described (44). All the behavioral experiments were
performed during the light phase and the experimenters are blind to the
genotype of each mouse. Both males and females have been used. All the
mice were kept in the behavioral test room in dim red light for one hour
before starting the experiments. For activity tests, mice were placed in
a pen holder with mashed surface (98mm height x 91mm diameter) for 5
min. The rearing number indicates the total number of events when the
animal lifted up at least two limbs. For open-field tests, mice were
placed in a 30 x 30 x 40 cm white Plexiglas chamber (equipment from
Med-Associates) in a behavior room, and locomotion was captured by
camera on top of the chamber and recorded for 15 min. The traveling
trace and distance were then analyzed by the Med-Associates Activity
Monitor program.