Increase of mushroom spine density in CA1 apical dendrites produced by water maze training is prevented by ovariectomy

Loss of Nogo receptor homolog NgR2 alters spine morphology of CA1 neurons and emotionality in adult mice

“…Here it should be noted that relative proportions of spine subtypes reported in fixed tissue in the CA1 region vary in the literature. We report here a higher proportion of stubby spines relative to mushroom spines, which has also been observed by Beltrán-Campos and co-workers and Sanders and co-workers (Beltrán-Campos et al, 2011; Sanders et al, 2012), whereas other studies have found the reverse ratio (Rauskolb et al, 2010; Görlich et al, 2012), or comparatively equal proportions of both subtypes (Lee et al, 2008). These differences are most likely accounted for by methodological differences between studies, particularly with regards to whether spine subtype characterization was carried out with computational or observational methods, and the dendritic branch order of analyzed spines.…”

Activation of ERβ modulates fear generalization through an effect on memory retrieval

“…A wealth of evidence demonstrates that estrogens play a major role in sex differences in behavior and that estrogens act directly on the hippocampus to affect synaptic plasticity and learning and memory (Frye et al, 2000;Spencer-Segal et al, 2012). Acquisition of hippocampal-dependent memories is accompanied by increases in dendritic spines (for a review see Urbanska et al, 2012) in the CA1 region of male and female rats (Beltrán-Campos et al, 2011;Leuner et al, 2003), and dendritic spine density in the hippocampus is sensitive to estrogen levels. For instance, in the CA1 region of the hippocampus, dendritic spine density changes 30% across the stages of the estrous cycle in female rats with the highest density of dendritic spines seen during the proestrus stage, when estrogen levels are highest (Woolley and McEwen, 1992).…”

“…For instance, in the CA1 region of the hippocampus, dendritic spine density changes 30% across the stages of the estrous cycle in female rats with the highest density of dendritic spines seen during the proestrus stage, when estrogen levels are highest (Woolley and McEwen, 1992). In addition, ovariectomy, which reduces endogenous levels of estrogens, leads to a decrease in dendritic spine density (Beltrán-Campos et al, 2011;Gould et al, 1990). In ERβ knockout mice (BERKO), LTP is reduced and hippocampal-dependent context fear conditioning is impaired (Day et al, 2005) whereas activation of ERβ increases LTP and dendritic branching in the hippocampus (Liu et al, 2008), suggesting that ERβ activation may be involved in estrogenic effects in synaptic plasticity and hippocampal-dependent learning and memory.…”

The evolving role of dendritic spines and memory: Interaction(s) with estradiol

“…The acquisition of new memories in a conditioning paradigm is associated with increased spine density in CA1 pyramidal cells in adult male rats (Leuner et al, 2003; Jedlicka et al, 2008) and female rats (Beltran-Campos et al, 2011). Performance on two different spatial memory tasks, the Morris water maze and object placement, is associated with a higher dendritic spine density on pyramidal cells in CA1 (Moser et al, 1994; Conrad et al, 2012; Eilam-Stock et al, 2012) suggesting that there is a morphological substrate for memory In addition, existing spines in the hippocampus undergo structural alterations that result in LTP (Jedlicka et al, 2008; Leuner et al, 2003).…”