Thigmotaxis, the tendency to move at the periphery of an open field, is characteristic of Ts65Dn mice; it may be evidence of anxiety or stereotypy (Simon et al., 1994). To estimate the effects of Kcnj6 dose on thigmotactic behavior, distance and time on arena periphery were assessed (Fig. 3, C, D). Both parameters were greater in Ts65Dn:Kcnj6+++ vs. 2N:Kcnj6++ mice (ambulatory distance: F1,21 = 2.12, p = 0.02; ambulatory time: F1,24 = 1.91, p = 0.03). Removal of an extra copy of Kcnj6 had no impact on these parameters, which were equal in Ts65Dn:Kcnj6+++ and Ts65Dn:Kcnj6++− mice (ambulatory distance: F1,20 = 0.70, p = 0.25; ambulatory time: F1,21 = 0.60; p = 0.28). Thus, Kcnj6 gene dose had no apparent effect on locomotion in the Ts65Dn mouse.
