Intergenerational effects of maternal separation on cognitive abilities of adolescent rats

Early life adversity (ELA) is a predisposing factor for the development of behavioral and emotional disorders later in life. In humans, primates and rodents, interruption in the mother-infant relationships, and disorganized maternal care negatively influence appropriate behavioral responses and may cause cognitive deficits. Epidemiological studies suggest that ELA-induced behavioral alterations can be transmitted across generations. In this study, we investigated the cognitive abilities of male and female rats in the second filial (F₂ ) generations whose mother, father, or both of their parents were undergoing a 180 min/day maternal separation (MS) paradigm during infancy (postnatal day (PND) 1-21). Cognitive abilities (in the open field, Morris water maze, and social interaction task) of F₂ pups were tested during adolescence. Our results showed that although the mother-MS group of both sexes showed normal cognitive behavior, father-MS female pups showed more anxiety in the open field, and social interaction and spatial memory impaired in this group. These impairments were not pronounced in every detail in father-MS male pups. Moreover, rat pups that both parents experienced MS during infancy, showed normal cognitive behavior. Our data support the idea that MS-induced cognitive impairments could be transmitted across generations. Considerably, the experiences of one's parents could be inherited in the following generation in a sex-dependent manner.