Fig. 1: TcMAC21 mice exhibit lower motor control skill and altered vocalization.

A Schematic presentation of the Erasmus Ladder which consists of a horizontal ladder situated between two shelter boxes. The mouse begins the task from inside the start box for a random time interval that varies between 9 and 18 s before it is allowed to walk on the ladder. When the time interval has passed, the LED light in the start box turns on and the mouse is allowed to start. The light remains on until the mouse reaches the goal box. Inter-limb coordination is tested during Days 1-4. Each daily session consisted of 40 trials, during which the mice had to walk back and forth between the goal and start boxes. Mice usually stepped on the upper rungs and only infrequently touched the lower ones, referred to as missteps. Locomotion adaptation is tested during challenge sessions (Days 5-8) when the mice learned to adapt their walking patterns in response to a 15 kHz auditory stimulus (CS) preceding the appearance of a raised rung (US) in their pathway. The US was located on the right side of the mouse and its movement specifically depended on the predicted position of the mouse on the ladder but was otherwise randomized. The blue and gray dots represent the upper and lower rungs, respectively. The position of the obstacle is indicated with a red dot and arrow during the challenge sessions. B Mean number of missteps per trial during the inter-limb coordination test were obtained from n = 9 mice of each genotype. TcMAC21 mice made significantly more missteps when traversing the ladder rungs compared to euploid controls. C TcMAC21 steptime had a longer latency during inter-limb coordination test. D TcMAC21 mice made a lesser proportion adapting long-stride pattern. E The first day of the challenge session (Day 5), TcMAC21 exhibited a greater increase in mean latency (“post-rise step time”) in response to the raised rung. F Representative sonograms of the four types of neonatal separation vocalizations. G TcMAC21 neonates (n = 12 neonates of each genotype) made significantly more total number of calls and H reduced vocalization tonality (signal-to-noise ratio) during separation-induced vocalizations. I No genotype difference in the mean vocalization frequency or (J) duration of calls produced. Data presented on a mouse-by-mouse basis. Data represent mean ± SEM.; *p < 0.05; **p < 0.01; black: Eu, red: TcMAC21.