Early life stress concept: introduction

Abstract

Rationale/statement of the problem : Stressful experiences during early life can remodel brain circuitry underlying behavioral adaptation with consequences for resilience and vulnerability to emotional and cognitive disorders. At least in the rodent this apparent permanent outcome of early adversity can be modulated by maternal influences and depends on the later life environmental context with the stress hormones of the hypothalamus-pituitary-adrenal axis in the driver's seat. A frequently investigated model is the animal that has experienced as pup reduced maternal care. Such a period of early neglect enhances the pup's responsivity to adverse emotional experiences, an effect that can even be detected within families and was found to advance prematurely the development of emotional and fear circuitry. Alternatively, enhanced care is capable of overridingthe lasting impact of neurotoxicity in early life. For instance, the frequently reported adverse effect of early life treatment with dexamethasone (as life-saving treatment of prematurely born infants) is strikingly attenuated by enhanced maternal care induced by daily handling. Methods : Dr. Nederhof will review recent animal and human studies supporting the cumulative stress and mismatch hypotheses. Dr. Parker will present behavioral and neuroendocrine data from monkey studies supporting the idea of stress inoculation following early exposure to moderate stressors. Dr. Bagot will address the importance of later-life context when investigating the effects of early-life experience using rats exposed as pups to varying levels of maternal care and ex-vivo electrophysiology. Dr. Vinkers will demonstrate in healthy volunteers a modulation by genotype and gender of the accumulating effects of stress on psychiatric outcome

Keywords

• early life stress
• behavioral adaptation
• resilience
• cognitive disorder
• maternal care
• signaling pathways