Synaptic Remodeling in the Dentate Gyrus, CA3, CA1, Subiculum, and Entorhinal Cortex of Mice: Effects of Deprived Rearing and Voluntary Running

Abstract

Hippocampal cell proliferation is strongly increased and synaptic turnover decreased after rearing under social and physical deprivation in gerbils (Meriones unguiculatus). We examined if a similar epigenetic effect of rearing environment on adult neuroplastic responses can be found in mice (Mus musculus). We examined synaptic turnover rates in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex. No direct effects of deprived rearing on rates of synaptic turnover were found in any of the studied regions. However, adult wheel running had the effect of leveling layer-specific differences in synaptic remodeling in the dentate gyrus, CA3, and CA1, but not in the entorhinal cortex and subiculum of animals of both rearing treatments. Epigenetic effects during juvenile development affected adult neural plasticity in mice, but seemed to be less pronounced than in gerbils.

Developmental neuroplasticity and the origin of neurodegenerative diseases

“…adulthood (Schaefers et al 2010;Schaefers 2012). These findings emphasize the significance of earlylife impacts making the brain vulnerable to maladaptive responses to additional challenges in adulthood.…”

Transient cell assembly networks encode stable spatial memories

“…However, if the cell assemblies rewire sufficiently slowly, the information encoded in the hippocampal map remains stable despite the connectivity transience in its neuronal substrate. Thus, the plasticity of neuronal connections, which is ultimately responsible for the network's ability to incorporate new information [69][70][71][72], does not necessarily degrade the information that is already stored in the network. These results present a principal development of the model outlined in [38,39,46] from both a computational and a biological perspective.…”

Treadmill Exercise Induces Hippocampal Astroglial Alterations in Rats

“…However, relatively little is known about mechanisms underlying these benefits [2, 38]. Synaptic remodeling in hippocampus induced by physical exercise has been described in animal models (e.g., [39]). Astrocytes have been shown to play an important role in synaptic remodeling [40–42] and protecting the CNS against various pathologies [43].…”