Fureix Carole, Walker Michael, Harper Laura, Reynolds Kathryn, Saldivia-Woo Amanda, Mason Georgia
Animal Biosciences, University of Guelph, Ontario N1G 2W1, Canada.
Animal Biosciences, University of Guelph, Ontario N1G 2W1, Canada.
Behav Brain Res. 2016 May 15;305:186-90. doi: 10.1016/j.bbr.2016.02.005. Epub 2016 Feb 10.
Depressive-like forms of waking inactivity have been recently observed in laboratory primates and horses. We tested the hypotheses that being awake but motionless within the home-cage is a depression-like symptom in mice, and that in impoverished housing, it represents an alternative response to stereotypic behaviour. We raised C57BL/6 ('C57') and DBA/2 ('DBA') females to adulthood in non-enriched (n=62 mice) or enriched (n=60 mice) cages, observing home-cage behaviour during the active (dark) phases. We predicted that being still but awake would be reduced by environmental enrichment; more pronounced in C57s, as the strain most prone to learned helplessness; negatively related to stereotypic behaviour; and positively related to immobility in Forced Swim Tests (FST). Compared to enriched mice, non-enriched subjects did spend more time spent being inactive but awake, especially if they displayed relatively little stereotypic behaviour. C57 mice also spent more time awake but motionless than DBAs. Furthermore, even after statistically controlling for housing type and strain, this behaviour very strongly tended to predict increased immobility in the FST, while high levels of stereotypic behaviours in contrast predicted low immobility in the FST. Being awake but motionless is thus a reaction to non-enriched housing that seems to be an alternative to stereotypic behaviour, and could reflect depression-like states.
最近在实验用灵长类动物和马匹中观察到了类似抑郁的清醒不动状态。我们检验了以下假设：在笼内清醒但不动是小鼠的一种类似抑郁的症状，并且在饲养条件匮乏的情况下，它是对刻板行为的一种替代反应。我们将C57BL/6（“C57”）和DBA/2（“DBA”）雌性小鼠饲养至成年，饲养环境分为非丰富环境（n = 62只小鼠）或丰富环境（n = 60只小鼠），并在活跃（黑暗）阶段观察笼内行为。我们预测，环境丰富会减少静止但清醒的状态；在最易出现习得性无助的C57品系小鼠中更为明显；与刻板行为呈负相关；与强迫游泳试验（FST）中的不动时间呈正相关。与处于丰富环境中的小鼠相比，处于非丰富环境中的小鼠确实花费了更多时间处于不活动但清醒的状态，尤其是那些表现出相对较少刻板行为的小鼠。C57小鼠清醒但不动的时间也比DBA小鼠更多。此外，即使在对饲养类型和品系进行统计学控制之后，这种行为仍非常强烈地倾向于预测FST中不动时间的增加，而高水平的刻板行为则相反，预测FST中不动时间较短。因此，清醒但不动是对非丰富饲养环境的一种反应，似乎是刻板行为的一种替代方式，并且可能反映出类似抑郁的状态。
