Lifetime development of behavioural phenotype in the house mouse (Mus musculus)

Abstract

With each trajectory taken during the ontogeny of an individual, the number of optional behavioural phenotypes that can be expressed across its life span is reduced. The initial range of phenotypic plasticity is largely determined by the genetic material/composition of the gametes whereas interacting with the given environment shapes individuals to adapt to/cope with specific demands. In mammalian species, the phenotype is shaped as the foetus grows, depending on the environment in the uterus, which in turn depends on the outer environment the mother experiences during pregnancy. After birth, a complex interaction between innate constitution and environmental conditions shapes individual lifetime trajectories, bringing about a wide range of diversity among individual subjects.In laboratory mice inbreeding has been systematically induced in order to reduce the genetic variability between experimental subjects. In addition, within most laboratories conducting behavioural phenotyping with mice, breeding and housing conditions are highly standardised. Despite such standardisation efforts a considerable amount of variability persists in the behaviour of mice. There is good evidence that phenotypic variation is not merely random but might involve individual specific behavioural patterns consistent over time. In order to understand the mechanisms and the possible adaptive value of the maintenance of individuality we review the emergence of behavioural phenotypes over the course of the life of (laboratory) mice. We present a literature review summarizing developmental stages of behavioural development of mice along with three illustrative case studies. We conclude that the accumulation of environmental differences and experiences lead to a “mouse individuality” that becomes increasingly stable over the lifetime.

Periadolescent Maturation of GABAergic Hyperpolarization at the Axon Initial Segment

“…Gramicidin-based perforated patch recordings, which preserve endogenous chloride gradients, were made from prefrontal pyramidal cells in acute slices prepared from postnatal day (P)11 to P72 mice, spanning mouse adolescent development (Brust et al, 2015). Pyramidal cells in layer 2/3 were targeted, as these neurons are postsynaptic to both basket and chandelier cells (Le Magueresse and Monyer, 2013).…”

An overview of maternal separation effects on behavioural outcomes in mice: Evidence from a four-stage methodological systematic review

“…Several MS studies used artificial heating to avoid possible effects from hypothermia as a confounding variable in mice pups. Their body temperature during the early postnatal days is dependent on the dam, primarily because the pups have not yet developed their own fur for thermal regulation (in C57BL/6 and BALB/c usually at PND 9-10) (Brust et al, 2015;Jackson Laboratory, 2012). Thermal regulation is considered one of the main maternal regulators involved in the development of different infant systems, including metabolic, neuroendocrine, neurochemical, central and autonomic nervous systems, during development.…”

Adolescent Mice Are Resilient to Alcohol Withdrawal-Induced Anxiety and Changes in Indices of Glutamate Function within the Nucleus Accumbens

“…Due to the relatively brief duration of mouse adolescence (Brust et al, 2015), all animals were subjected to a 14-day drinking period. This drinking period is similar to that employed in other studies of adolescent alcohol exposure (Spear, 2000b; Brunell and Spear, 2005; O’Tousa et al, 2013) and enables the extension of prior immunoblotting work (Cozzoli et al, 2012, 2014, 2016) to a shorter history of binge-drinking in adult animals.…”