Time-Dependent Changes in Cortisol and Tympanic Temperature Lateralization During Food Deprivation Stress in Marmoset Monkeys

Abstract

Temporal information about food availability can be easily entrained, as in the case of fixed feeding routines of captive animals. A sudden unintentional or deliberate delay (e.g., food deprivation—FD) leads to frustration and psychological stress due to the loss of temporal predictability. How marmosets—an increasingly used small primate—process and respond to FD stress has not been previously assessed. Here we delayed the routine feeding of adult captive marmosets for 3 or 6 h. Blood cortisol concentration was used as a hormonal measure of the stress response. Changes in the left/right baseline tympanic membrane temperature (TMT) were used as an indirect ipsilateral indicator of hemisphere activity. Marmosets that were deprived for 3 h had higher cortisol levels than non-deprived controls. Cortisol concentration in the marmosets deprived for 6 h did not differ from controls possibly due to adaptative mechanisms against the detrimental effects of prolonged high cortisol levels. Interestingly, FD stress may have been processed more symmetrically at first, as indicated by the bilateral increase in TMT at the 3 h interval. As the event progressed (i.e., 6 h), a clear rightward TMT bias suggests that hemisphere activity had become asymmetrical. Therefore, the sudden loss of temporal predictability of an entrained routine feeding schedule induces time-dependent changes in the cortisol stress response and shifts in the TMT (and potentially hemisphere activity) lateralization bias of adult captive marmosets.

Body surface temperature of rats reveals both magnitude and sex differences in the acute stress response

“…These asymmetries could also be investigated using IRT to assess emotional valence [44]. As with the tympanic membrane temperature, the eye temperature was interpreted in this study to reflect the brain temperature of the same side [142,143]. The mechanism of thermal lateralisation is not clear but it could be due to lateralised cerebral blood flow, sympathetic innervation or activation of corticosteroid receptors [140,141,44,144].…”

Differential Ageing of the Brain Hemispheres: Evidence from a Longitudinal Study of Hand Preferences in Common Marmosets

“…Depending on whether this effect is more widespread in the hemisphere and, since glucocorticoids are associated with ageing [57,58], a cumulative effect of stress with ageing is a potential explanation for declining strength of left-hand preference. Additionally, it has been found in marmosets that stress caused by unexpected and longer-term food deprivation effects the blood flow to, and activity of, the right hemisphere more than the left hemisphere [59], which is consistent with a greater effect of ageing on the right-hemisphere control of left-hand use.…”

Knowledge of lateralized brain function can contribute to animal welfare

“…This flexibility means that laterally biased behavior can indicate conditions of acute and chronic stress. In fact, somewhat prolonged stress caused by deprivation of food has been shown to elevate the activity of the right hemisphere, as Pereira et al (75) found in marmosets by measuring tympanic membrane temperature. Such flexibility in lateralization could be utilized to develop strategies to alter the strength and direction of laterality, thereby altering the reactions of animals to specific conditions and events (76).…”