Fig. 2

Consequences of defined gray matter encephalitis on social recognition memory and thermoregulation in the SocioBox. a SocioBox experiments were performed using the 3 × tamoxifen cohort (DTA n = 16, control n = 18). Infrared thermography recordings show test mouse during habituation 3 in an otherwise empty SocioBox (left side) and during exposure to 5 stimulus mice (right side). Note the presence of the divider (partition) in the upper row that is lifted in the lower row. b Schematic outline of the 6 SocioBox trials. Habituations 1–3 were performed on 3 consecutive days, while exposure 1–2 and memory test were all performed on day 4. Each trial consisted of an initiation and interaction stage (5 min each; separated by divider lifting). During exposure, each test mouse (middle) was confronted with 5 stimulus mice (stimuli; S1-S5, light blue). For the memory test, 1 stimulus mouse was exchanged with a new mouse (“stranger”, S, red) unknown to the test mouse. c General activity during memory test was increased in DTA compared to control mice (total distance, total interaction time, visits to interaction zone), whereas the latency to first interaction zone and time/visit were similar. d DTA mice were significantly faster to approach the stranger than control mice. e Evaluation of social recognition memory in the SocioBox memory test: Comparing the interaction of DTA and control mice with their conspecifics showed that control mice spent more time with the stranger than with the stimulus mice and undertook more visits to the stranger than to stimulus mice. DTA mice displayed no differences in these parameters, indicating a lack of distinction between stimulus mice and stranger; for clarity, parameters given in % total interaction time and average of time spent with all 4 stimulus mice shown. Time per visit to stranger over stimuli tended to be increased in controls but not DTA mice. f Centralization Index (CI) was calculated by mean body temperature divided by mean tail temperature for every frame of recording. g–j CI changes of the test mice during SocioBox trials. Dotted line indicates partition lifting after 300 s; repeated measure mixed-model ANOVA, mean ± SEM presented. g During habituation 3, there were no CI differences between both groups, neither before (p = 9482) nor after partition lifting (p = 0.1839). h During first half of exposure 1, DTA mice showed a higher CI than controls, but no difference after partition lifting (p = 0.3960). i First half of exposure 2 showed no significant differences between both groups (p = 0.0979), but revealed higher CI of control mice during second half (p = 0.0407). Interestingly, control mice presented increased CI values towards partition lifting (250-350 s, light blue field). j During the memory test, differences between groups in first (p = 0.0732) or second half (p = 0.0996) were not significant, but controls exhibited higher CI values in anticipation of partition lifting (210-290 s, p = 0.0395, light blue field)