Environmental enrichment stimulates progenitor cell proliferation in the amygdala

Abstract

Enriched environments enhance hippocampal neurogenesis, synaptic efficacy, and learning and memory functions. Recent studies have demonstrated that enriched environments can restore learning behavior and long-term memory after significant brain atrophy and neural loss. Emotional and anxiety-related behaviors were also improved by enriched stimuli, but the effect of enriched environments on the amygdala, one of the major emotion-related structures in the central nervous system, remains largely unknown. In this study, we have focused on the effects of an enriched environment on cell proliferation and differentiation in the murine amygdala. The enriched environment increased bromodeoxyuridine (BrdU)-positive (newborn) cell numbers in the amygdala, almost all of which, immediately after a 1-week period of enrichment, expressed the oligodendrocyte progenitor marker Olig2. Furthermore, enriched stimuli significantly suppressed cell death in the amygdala. Some of the BrdU-positive cells in mice exposed to the enriched environment, but none in animals housed in the standard environment, later differentiated into astrocytes. Our findings, taken together with previous behavioral studies, suggest that progenitor proliferation and differentiation in the amygdala may contribute to the beneficial aspects of environmental enrichment such as anxiolytic effects.

Distribution and fate of DCX/PSA-NCAM expressing cells in the adult mammalian cortex: A local reservoir for adult cortical neuroplasticity?

“…Recent studies suggest the presence of adult-born neurons or immature neurons in several regions of the adult mammalian central nervous system outside the canonical neurogenic niches, including cortical areas (Kaplan, 1981;Dayer et al, 2005;Takemura, 2005;Shapiro et al, 2007aShapiro et al, , 2007bShapiro et al, 2009;de la Rosa-Prieto et al, 2010), subcortical areas (Bédard et al, 2002;Bernier et al, 2002;De Marchis et al, 2004;Vessal et al, 2007;Okuda et al, 2009;Pierce and Xu, 2010;Ehninger et al, 2011;Dirian et al, 2014;Ernst et al, 2014;Luzzati et al, 2014), and the spinal cord (Shechter et al, 2007). In humans, histological and carbon-14 dating approaches revealed that adult-born interneurons could integrate into the striatum (Ernst et al, 2014).…”

Adult Neurogenesis and Mental Illness

“…Adult neurogenesis has been reported in the amygdala of rodents and monkeys (Bernier et al, 2002;Jiang et al, 2014;Takemura, 2005), although the evidence for double labeling of the proliferation marker BrdU and mature neuronal markers is not especially strong. Effects of olfactory bulbectomy, fear conditioning, and fluoxetine have been observed on the numbers of adult-born cells in the amygdala Keilhoff et al, 2006;Okuda et al, 2009), but it is unclear how many of the affected cells are neurons.…”

Hyperforin promotes mitochondrial function and development of oligodendrocytes

“…ECT also induces cell proliferation in the adult rat prefrontal cortex, and 60% of the newly generated cells have been identified as oligodendrocytes or endothelial cells (Madsen et al, 2005). Environment enrichment has been found to reduce depressive-like behavior in animal model, stimulate proliferation of oligodendrocyte progenitor cells (OPCs) and prevent cell death of OPCs in the mouse amygdala (Brenes et al, 2008;Okuda et al, 2009 (Medina et al, 2006). In the 1500s, the Swiss physician Paracelsus first used SJW as treatment for psychiatric disorders, such as anxiety, neurosis and depression (Bilia et al, 2002).…”