A new study appearing in the October issue of Behavioral Neuroscience suggests that motherhood may cause the brain to grow. Preliminary research published by the American Psychological Association (APA) found that the brains of new mothers bulked up in areas linked to motivation and behavior, and that mothers who raved the most about their new offspring showed the greatest growth in key parts of the mid-brain.[audio:http://hospitalstay.com/wp-content/uploads/2010/10/18-Plug-In-Baby-2.mp3|titles=Plug In Baby]

Animal studies suggest that structural changes occur in the maternal brain during the early postpartum period in regions such as the hypothalamus, amygdala, parietal lobe, and prefrontal cortex and such changes are related to the expression of maternal behaviors. In an attempt to explore this in humans, the study conducted a prospective longitudinal study to examine gray matter changes of mothers’ brains at two time points: 2–4 weeks postpartum and 3–4 months postpartum. Comparing gray matter volumes across these two time points, the study found increases in gray matter volume of the prefrontal cortex, parietal lobes, and midbrain areas. This increased gray matter is associated with maternal positive perception of her baby.

The study raises questions about the interaction between mother and child (or parent and child, since fathers are also the focus of study). The intense sensory-tactile stimulation of a baby may trigger the adult brain to grow in key areas, allowing mothers, in this case, to “orchestrate a new and increased repertoire of complex interactive behaviors with infants,” the authors wrote.

The mothers averaged about 33 years in age and an education of at least 18 years. All mothers were breastfeeding, nearly half had other children and none had serious postpartum depression. The study also suggested that postpartum depression may involve reductions in the same brain areas that grew in mothers who were not depressed. “The abnormal changes may be associated with difficulties in learning the rewarding value of infant stimuli and in regulating emotions during the postpartum period,” the authors noted.

Sources:  Medical News Today; APA

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