Long-Term Effects of Maternal Separation During Infancy

As a follow-up to one of my previous posts regarding the long-term effects of variations in maternal care on learning abilities of offspring, I chose to explore the long-term effects of maternal absence or separation on offspring and development. This led me to a study conducted by Romeo et al., which utilized open-field tests and elevated-plus maze tests to measure how fear/anxiety behaviors in adult mice were effected by maternal separation during infancy. This video below gives a sense for what exactly occurs during an open-field test.

Several previous studies suggest negative consequences in adulthood that result from physical and emotional neglect in childhood. This negative consequences include a higher likelihood to develop anxious or depressive behaviors in adulthood. Thus, the Romeo et al. study explores the lasting influence of early-life stressors on adulthood behaviors. They examined both males and females and, interestingly, found very different effects of MS (maternal separation) with respect to the sex of the subject. In male mice that experienced MS in the neonatal period, open-field tests and elevated-pus maze tests indicated that these male mice displayed significantly higher levels of anxiety and fear behaviors then those of the control mice. On the other hand, female mice that underwent the same tests displayed reduced anxiety and fear behaviors, however the females only demonstrated this reduction of anxiety/fear during the diestrous phase of their estrous cycle.

Ultimately, these results indicate that maternal separation can determine emotionality of adult male and female mice; however the degree and expression of this effects depends upon both the SEX and the PHASE of the estrous cycle of the female subject.


To view the full Romeo et al. article, follow this link.