Figure 8

Corticosterone and locomotion dynamics in the 5-day head-fixed protocol followed by the stress-sensitive behavioral paradigms. (a) Experimental timeline: daily 60-min head-fixed sessions for 5 days followed by behavioral paradigms: the open field and the forced-swim tests (day 6, D6), the elevated plus maze (D7), nesting behavior (overnight D7/8), two-bottle choice (D8-9); two head-fixed groups: one with the air-lifted container (floating) and another with the container fixed to the base (stationary); blood sampling days (BS#). (b–d) Blood corticosterone concentration; n = 4 in each group. (b, c) Individual animal data. (d) Similar blood corticosterone level in both groups with a significant drop 5 days after the last head-fixed session at D10: two-way RM ANOVA followed by Bonferroni’s post hoc tests (within groups), interaction, F(2, 12) = 0.3431, p = 0.7163; time, F(1.374, 8.245) = 21.63, p = 0.0009; group, F(1, 6) = 1.041, p = 0.3470; a star (*) = significant difference in comparison to D1 only (*p = 0.0208) and a hash (#) to D1 and to D5 (#p < 0.04). (e, f) Movement time analysis; n = 3 in each group. (e) Significantly longer movement time in the floating group: two-way RM ANOVA, interaction, F(4, 16) = 1.719, p = 0.1950; time, F(4, 16) = 2.084, p = 0.1306; group, F(1, 4) = 10.80, *p = 0.0303. (f) Stable proportion of the movement time during the head-fixed sessions (normalized to D1). (g–r) Behavioral experiments analyzed with the Mann–Whitney U test; the dashed line corresponds to the head-fixed group from the 25-day protocol; n = 4 in each group. (g, h, i) Open field test: longer latency to the first center entry in the stationary group (Mann–Whitney U value (MWU) = 0, *p = 0.0286). (j, k, l) Forced-swim test: no differences in any presented parameters. (m, n, o) Elevated plus maze: less attempts to the open arm in the stationary group (MWU = 0, *p = 0.0286). (p) Similar nesting quality score between the groups. (q) High sucrose preference score in both groups (= sucrose preference). (r) Data from the floating group: higher sucrose intake (MWU = 0; *p = 0.0286).