Stress axis programming generates long-term effects on cognitive abilities in a cooperative breeder

The ability to flexibly adjust behaviour to social and non-social
challenges is important for successfully navigating variable environments.
Social competence, i.e., adaptive behavioural flexibility in the social
domain, allows individuals to optimize their expression of social
behaviour. Behavioural flexibility outside the social domain aids in
coping with ecological challenges. However, it is unknown if social and
non-social behavioural flexibility share common underlying cognitive
mechanisms. Support for such shared mechanism would be provided if the
same neural mechanisms in the brain affected social and non-social
behavioural flexibility similarly. We used individuals of the
cooperatively-breeding fish Neolamprologus pulcher that
had undergone early-life programming of the
hypothalamic-pituitary-interrenal (HPI) axis by exposure to (i) cortisol,
(ii) the glucocorticoid-receptor antagonist mifepristone or (iii) control
treatments, and where effects of stress-axis programming on social
flexibility occurred. One year after the treatments, adults learned a
colour-discrimination task, and subsequently, a reversal-learning task
testing for behavioural flexibility. Early-life mifepristone treatment
only marginally affected learning performance, whereas cortisol treatment
significantly reduced behavioural flexibility. Thus, early-life cortisol
treatment reduced both social and non-social behavioural flexibility,
suggesting a shared cognitive basis of behavioural flexibility. Further
our findings imply that early-life stress programming affects the ability
of organisms to flexibly cope with environmental stressors.