Adult Hippocampal Neurogenesis in Natural Populations of Mammals

Abstract

This review will discuss adult hippocampal neurogenesis in wild mammals of different taxa and outline similarities with and differences from laboratory animals. It begins with a review of evidence for hippocampal neurogenesis in various mammals, and shows the similar patterns of age-dependent decline in cell proliferation in wild and domesticated mammals. In contrast, the pool of immature neurons that originate from proliferative activity varies between species, implying a selective advantage for mammals that can make use of a large number of these functionally special neurons. Furthermore, rapid adaptation of hippocampal neurogenesis to experimental challenges appears to be a characteristic of laboratory rodents. Wild mammals show species-specific, rather stable hippocampal neurogenesis, which appears related to demands that characterize the niche exploited by a species rather than to acute events in the life of its members. Studies that investigate adult neurogenesis in wild mammals are not numerous, but the findings of neurogenesis under natural conditions can provide new insights, and thereby also address the question to which cognitive demands neurogenesis may respond during selection.

Predators inhibit brain cell proliferation in natural populations of electric fish, Brachyhypopomus occidentalis

“…In many vertebrate taxa, animals in natural populations add brain cells at greater rates than those living in captivity [2,[4][5][6]. One motivation of our study was to address whether the presence of predators, an important feature of most natural habitats, constitutes an environmental enrichment that contributes positively to greater brain cell proliferation in the wild or an environmental stressor that negatively affects brain cell production.…”

Evolutionary Shaping of Adult Hippocampal Neurogenesis in Mammals–Cognitive Gain or Developmental Priming of Personality Traits?

“…Differences between orders and species emerge primarily in the time course of the decay within a span of 2 years, and in the molecular differentiation of the newly generated cells (Amrein, 2015). Up to now, a coherent picture of how species differences in AHN relate to ecological conditions must remain speculative, chiefly because of low sample sizes and problems in quantifying age levels.…”

New neurons in the adult striatum: from rodents to humans

“…Radiocarbon-14 dating cannot be used in rodents due to their relatively short lifespan, while bromodeoxyuridine (BrdU), the gold standard for cell birthdating, is rarely be used in humans. Endogenous markers of immature neurons, such as DCX have been tremendously useful for identifying young neurons in many species and brain regions [10,48], but they are unsuitable for cross-species rate comparisons due to differential rates of cell death, maturation and consequent downregulation of DCX, and postmortem stability across species [49–51]. …”