Can biomarkers of biological age be used to assess cumulative lifetime experience?

Objective methods for assessing the cumulative lifetime experience of non-human animals would be valuable. We develop the hypothesis that biological age is a common currency that integrates the overall quality of an animal’s lifetime experience across a range of types of exposure. Ageing is the result of the accumulation of somatic damage, and its rate […]

Stress impairs spatial but not early stimulus–response learning

Recent evidence indicates that stress modulates multiple memory systems, favoring caudate nucleus based stimulus–response learning at the expense of hippocampus-based spatial learning. Whether this is due to a facilitating effect of stress on stimulus–response learning, an impairing effect on spatial learning, or both, is not known. To answer this question, mice were either subjected to […]

A critical review of chronic stress effects on spatial learning and memory

The purpose of this review is to evaluate the effects of chronic stress on hippocampal-dependent function, based primarily upon studies using young, adult male rodents and spatial navigation tasks. Despite this restriction, variability amongst the findings was evident and how or even whether chronic stress influenced spatial ability depended upon the type of task, the […]

Sex differences in learning processes of classical and operant conditioning

Males and females learn and remember differently at different times in their lives. These differences occur in most species, from invertebrates to humans. We review here sex differences as they occur in laboratory rodent species. We focus on classical and operant conditioning paradigms, including classical eyeblink conditioning, fear-conditioning, active avoidance and conditioned taste aversion. Sex […]

Predation threat exerts specific effects on rat maternal behaviour and anxiety-related behaviour of male and female offspring

Differences in the rate of maternal behaviours received by rodent offspring are associated with differential programming of molecular and behavioural components of anxiety and stress-related functions. To determine the degree to which maternal behaviours are sensitive to environmental conditions, Long–Evans rat dams were exposed to the odour of a predator (cat) at two different time […]

Effects of chronic stress: A comparison between tethered and loose sows

The present study aimed to investigate whether long-lasting, recurrent tethering of sows leads to enduring effects on measures that may be indicative of chronic stress. Sows that had experienced tethering for about 1.5 or 4.5 years and age-matched sows kept in a social housing system (loose sows) were compared. Immediately after slaughter, blood samples were taken […]

Sex differences in the effects of two stress paradigms on dopaminergic neurotransmission

Sex differences in behavioral and neurobiological responses to stress are considered to modulate the prevalence of some psychiatric disorders, including major depression. In the present study, we compared dopaminergic neurotransmission and behavior in response to two different stress paradigms, the Forced Swim Test (FST) and the Chronic Mild Stress (CMS). Male and female rats were […]

Effects of pregnancy on spatial cognition in female Hooded Long-Evans rats

Studies examining the roles of estrogens and progestins on spatial cognition have been highly contradictory. To determine if the hormonal environment of pregnancy affects spatial cognition, pregnant (n = 7) and virgin (n = 7) Hooded Long-Evans rats were tested in a Morris water maze throughout the 3 weeks of pregnancy and the second week postpartum. Latency to platform, […]

Corticosteroids in relation to fear, anxiety and psychopathology.

Corticosteroids play extremely important roles in fear and anxiety. The mechanisms by which corticosteroids exert their effects on behavior are often indirect, because, although corticosteroids do not regulate behavior, they induce chemical changes in particular sets of neurons making certain behavioral outcomes more likely in certain contexts as a result of the strengthening or weakening […]

Prenatal origins of individual variation in behavior and immunity

The in utero environment plays a critical role in initiating the normal ontogeny of many physiological systems. As a consequence, disturbances during prenatal life can affect the baby’s maturational trajectory and sometimes cause chronic alterations that influence health postpartum. Our review summarizes a series of studies in rhesus monkeys supporting these conclusions. Psychological disturbance or […]