PMC4722345_01
Enhanced spatial memory in offspring of mothers with physical activity during pregnancy. Transgenic (tg) and wild type (wt) mice modelling Alzheimer's disease were tested for spatial memory in a Barnes maze. The mothers of half of the animals were physically active by using a running wheel (RW) during pregnancy while the other mothers lived in standard housing (SH) conditions without access to a running wheel. None of the mice tested as adults at an age of 136 days had access to a running wheel themselves. Offspring of running mothers performed significantly better in the test, indicating a long lasting effect of environmental conditions during pregnancy on cognitive behaviour in adult offspring. Figure redrawn after.
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F2
Figure 2 shows data from a study conducted with a transgenic model of Alzheimer's disease.
PMC4722345_02
Repeatability of activity measures increases with age. 40 female mice (strain C57BL/6) were housed in a semi naturalistic environment and automatically tracked using RFID transponders and 20 Ring antennas. Activity was measured from PND 35 (mid adolescence) to PND 125 (adulthood) by total antenna contacts measured in bouts of 5 days. The figure shows the repeatabilites taken from generalised linear mixed models (GLMM) including age at testing as a fixed and animal ID as a random factor. Each repeatability measure is calculated over three adjacent measurements of activity. The grouping of data is indicated on the x-axis. In green, the 95% confidence intervals of the repeatabilities are given. With the exception of the very first repeatability measurement taken between day 35 and 45, all repeatabilities are significant. As a general trend, the older the animals grew, the better the predictability for their future activity got.
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F3
In order to show changes in repeatabilities over time, we split the data up in six blocks of three adjacent measurements each and calculated separate models for each block (Figure 3).
PMC4722345_03
Persistent individual differences despite standardisation. 40 female mice of the inbred strain C57BL/6 were kept in strictly standardised conditions and tested at PND 85 and PND 120 in an open field (OF) test for locomotor behaviour. Despite genetic and environmental standardisation considerable individual differences emerged in both tests. Pearson's product-moment correlation analysis revealed a significant correlation between the different tests explaining 13% of the variance. Additionally to the regression line (black) the 95% confidence band (inner red lines) and the 95% prediction band (outer blue lines) are drawn.
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F4
The results shown in Figure 4 (redrawn from) demonstrate that there is a considerable variation in locomotor activity in both of the OF tests despite using inbred mice and all efforts of laboratory environment standardisation.