Aerobic exercise is the critical variable in an enriched environment that increases hippocampal neurogenesis and water maze learning in male C57BL/6J mice

Abstract

Previous studies have shown that housing mice with toys and running wheels increases adult hippocampal neurogenesis and enhances performance on the water maze. However, the relative contribution of running versus enrichment to the neurogenic and pro-cognitive effects is not clear. Recently, it was demonstrated that enrichment devoid of running wheels does not significantly enhance adult hippocampal neurogenesis in female C57BL/6J mice. However, novel toys were not rotated into the cages, and dietary enrichment was not included, so it could be argued that the environment was not enriched enough. In addition, only females were studied, and animals were group-housed, making it impossible to record individual running behavior or to determine the time spent running versus exploring the toys. Therefore, we repeated the study in singly housed male C57BL/6J mice and enhanced enrichment by rotating novel tactile, visual, dietary, auditory, and vestibular stimuli into the cages. Mice were housed for 32 days in one of 4 groups: running-only, enrichment-only, running plus enrichment, and standard cage. The first 10 days BrdU (bromodeoxyuridine) was administered to label dividing cells. The last 5 days mice were tested on the water maze, and then euthanized to measure number of BrdU cells co-labeled with NeuN (neuronal nuclear marker) in the dentate gyrus. Mice in the running-only group ran, on average, greater distances than animals in the running plus enrichment group. The combination of enrichment and running did not significantly increase hippocampal neurogenesis any more than running alone did. Animals in the running-only condition were the only group to show enhanced acquisition on water maze relative to standard cage controls. We confirm and extend the conclusion that environmental enrichment alone does not significantly increase hippocampal neurogenesis or bestow spatial learning benefits in male C57BL/6J mice, even when the modalities of enrichment are very broad.

Exercise as a pro-cognitive, pro-neurogenic and anti-inflammatory intervention in transgenic mouse models of Alzheimer’s disease

“…At a behavioural level, improvements in spatial learning and memory, associative learning and recognition memory have all been observed in animals following exercise training. Mice housed with a running wheel perform better in the MWM compared to their sedentary counterparts (Clark et al, 2008;Gibbons et al, 2014;Mustroph et al, 2012), while exercising mice also outperformed their sedentary counterparts in the contextual fear conditioning task (Bhattacharya et al, 2015;Clark et al, 2008;Gibbons et al, 2014). Data from our laboratory has demonstrated that rats trained on a treadmill perform better than their sedentary counterparts in the novel object recognition and object displacement tasks of recognition and spatial memory respectively (Griffin et al, 2009).…”

Effects of Walnut Polyphenol on Learning and Memory Functions in Hypercholesterolemia Mice

“…If a mouse didn't reach the platform in 60 s, it meant that its escape latency was 60 s, then the mouse was allowed to rest for 30 s between trials. On the fifth day, the platform was removed and mice were tasked with a probe trial for 2 min [31,32].…”

Changes in Structural and Functional Plasticity of the Brain Induced by Environmental Enrichment

“…ответе на возбуждение у животных при столкновении с новыми объектами [14] Теория обучения Посредником морфологических изменений являются клеточные механизмы, лежащие в основе процессов обучения [10] выживаемость нейронов у мышей [15]. Интересно, что ОС, не подразумевающая высокой моторной активно-сти, лишь незначительно стимулирует гиппокампальный нейрогенез [31], тогда как применение беговых колес способствует более интенсивной пролиферации клеток в зубчатой извилине у мышей, содержащихся в условиях социальной и физической депривации, по сравнению с мышами, содержащимися в условиях ОС [32]. Таким об-разом, факторы ОС, вероятнее всего, избирательно дей-ствуют на разные компоненты программы нейрогенеза, а также дополнительно дифференцированно стимулиру-ют глио-, синапто-и ангиогенез, как это было предло-жено W. Greenough и соавт.…”