The early 1990s saw more than 100,000 children in Romania surviving in overcrowded and under-funded orphanages. These children suffered from severe neglect and had little or no interaction with the caretakers. This lack of nurturing led to the alteration of the structure and function of their brains. These children developed a host of behavioral and emotional problems that many of them are still coping with today. Thus, neuroscientists at Northeastern University are studying rat brains to understand how trauma in infancy makes children.
Recently, they found that female rats developed abnormal connections between two areas of the brain in response to neglect. It is interesting to note that these are the same areas that show abnormal activity in brain scans of children raised in orphanages and those who suffered from child abuse or other maltreatment. Children with this abnormal activity are more likely to develop anxiety later on in childhood or adolescence. Now, they are trying to examine the connections between the basolateral amygdala, part of an almond-shaped structure tucked in near our temple and the prefrontal cortex, which is right behind the forehead.
The connections between the amygdala and the prefrontal cortex develop throughout childhood and adolescence. To figure out the exact mechanism behind this change, the researchers needed to be able to examine brains more directly. Hence, they needed rats. They removed male and female rat pups from their mothers for three to four hours every day during their infancy. The pups were separated into warm areas with bedding that smelled like their mother and littermates but without any physical contact or caretaking. They then injected a dye into each animal’s basolateral amygdala to identify them. They examined the rats’ brains at different points in development. They found marked differences between males and females. In female rats that were separated from their mother, an excess of new connections grew rapidly between the amygdala and the prefrontal cortex early on in development. Males saw some of this same nerve growth but not until much later on. Male and female brains mature differently, so this type of stress may be hitting females at a critical point in their development. Differences in hormones or immune systems could also play a role, or perhaps males and females simply experience stress in different ways. The important thing is that these changes don’t have to be permanent. Understanding the differences in how male and female brains develop and the impact of neglect on this process could help improve treatments and interventions for children before mental illnesses begin to manifest themselves.
Shahjadi Jemim Rahman