Figure 3: Lower exploration propensity is a characteristic phenotype of 129S mice.

A-B, Graphs depicting a decrease in the distance covered (cm, p<0.0001) and velocity (cm/s, p<0.0001) for B6 mice with neural implants and tethers (Mann-Whitney U test).

C-D, Graph illustrating no significant difference in distance (cm, p=0.13) and velocity (cm/s, p=0.21) for 129S mice with or without neural implants/tethers (Mann-Whitney U test).

E, Experimental setup for the open field task with extracellular recording in freely behaving B6 and 129S mice.

F, Graph comparing the mean distance for 129S and B6 mice in spatial exploration tasks (Mann-Whitney U test, p<0.0001).

G, Representative animal trail (center-body) depicting the total distance covered by a typical B6 and 129S mouse in an open field task.

H, Graph illustrating a lower mean velocity for 129S mice in open field tasks (Mann-Whitney U test, p<0.0001).

I-J, Graphs illustrating a lower activity duration (p=0.001) and higher inactivity duration (p<0.0001) for 129S mice (Mann-Whitney U test).

K, Representative heat maps demonstrating activity for a 129S mouse. Compared with the B6 mouse, the 129S mouse avoided the central area of the test chamber.

L, Graph showing lower mobility in open field tasks for the 129S group when compared with the B6 group (Mann-Whitney U test, p=<0.0001).

M, Comparisons of the velocity spread (Δcm/s) for 30-sec bins of open field (spatial exploration) tasks (two-way ANOVA, p<0.0001). B6 mice demonstrated robust exploratory behavior with sustained speed (chi-sq=0.6, p=0.43) for the task duration. 129S mice showed a significant decline in velocity, and a lower velocity score/bin for the open field tasks (chi-sq=4.2, p=0.04).

N, Cartoon illustration of a spatial exploration event during an open field test.

O, Sample of intervals with sustained exploration for a B6 and a 129S mouse.

P-Q, Graphs illustrating a low mean FR (p<0.0001) and burst rate (p<0.0001) scores for 129S putative pyr units, versus B6 putative units (Mann-Whitney U test).

R, Interval plot of FR (ΔFR) for putative pyr cells in open field tasks (two-way ANOVA, p<0.0001). Intervals depict six 15-sec bins for a 90-sec duration of exploration. The 129S pyr cells had low FR scores (spikes/sec) for the selected duration. No significant change was observed in ΔFR for B6 (chi-sq=0.162, p=0.69) or 129S (chi-sq=0.16, p=0.67) pyr neurons during open field tasks.

S, Graphs illustrating a lower mean FR for 129S putative int units during spatial exploration (Mann-Whitney U test; p=0.02).

T, Interval plot of FR (ΔFR) for putative int in open field tasks (two-way ANOVA, p=0.06). No significant change in ΔFR for B6 (chi-sq=0.28, p=0.59) or 129S (chi-sq=0.04, p=0.84) int was observed during open field tasks.