Summary: Bennett et al. (1984)

 Xerus inauris, commonly known as the Cape ground squirrel, is a diurnal, highly social, sciurid rodent that occurs in the arid regions of southern Africa. Squirrels are common in the southern Kalahari. The bushy tail of this species acts like a sunshade, allowing individuals to reduce environmental heat loads by raising the tail and shading the body. Bennett et al. (1984) measured the operative environmental temperature of squirrel mannequins oriented in different postures and with different tail orientations (late spring). At the same time, they observed naturally occurring thermoregulatory behaviour in a free-living colony. Bennett et al. (1984) noted a change in squirrel behaviour when environmental temperatures exceeded 40 C. Squirrels raised the tail over the body and turned their backs to the sun. By raising the tail over the body (to cover the head), the tail reduced the environmental temperature by over 5 C, allowing squirrels to increase time foraging above the surface (7h shaded vs. 3h unshaded). Squirrels also showed behavioural changes when the shaded temperature exceeded 40 C, by retreating into their cooler underground burrows.

Summary: Brassen et al. (2012)

Brassen et al. (2012)  noted that there is a deficit in information about the neurobiological mechanisms that underlie the relationship between age-related declines in the ability to undo regrettable situations and a reduction in engagement with these situations. They used a sequential risk-tasking task combined with a multimodal psychophysiological approach to investigate responsiveness to regret in young, aged emotionally successful and aged late-life depressed participants. Brassen et al. (2012) found that aged emotionally successful participants showed a reduction in responsiveness to regret that was paralleled by a corresponding neurobiological change in emotion regulation (autonomic and frontostriatal). They suggest that the ability to disengage from regretful events is critical for resilience of emotional health into old age.

Summary: Hart (2012)

 The ability to accurately determine an animal's level of pain and stress is crucial for the correct design and implementation of various handling and experimental procedures. Hart (2012) suggests that the quantification of physiological neuroendocrine responses could allow for an objective measure of associated stress and pain than behavioural observations alone. She notes that the hypothalamic-pituitary-adrenal (HPA) axis plays a large role in the neuroendocrine response  of an animal to various types of stressors (environmental,  emotional  and  physiological). This system is integrated with the production of cortisol, a glucocortiocoid stress hormone commonly used in behavioural studies as a measure of stress. Hart (2012) suggests that using the concentration of cortisol as a measure of objective stress assessment could be misinterpreted, as aspects of HPA physiology are often overlooked. She notes that using plasma cortisol concentration as a measure of stress can be useful in some cases, but notes that investigators should take into account the unique variable nature of HPA axis activation.