The Neuroscience of “Mother Knows Best”

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The Museum’s Health Sciences Department is partnering with the University of Colorado Anschutz Medical Campus to publish a monthly series on the Museum blog called “Know Health”. The articles focus on current health topics selected by CU’s medical and graduate students in order to provide both English and Spanish speaking communities with current, accurate information. The posts in the “Know Health” series are edited versions of articles that first appeared in Contrapoder magazine. Thank you to the students at the University of Colorado Anschutz Medical Campus for bringing these stories to life.

(aka Dr. Nicole Garneau, chair and curator, Health Sciences Department)

Guest Author, John Soltys is a student at the University of Colorado Anschutz Medical Campus in the School of Medicine.

(en español)

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“Mother knows best” is one piece of wisdom that is hard to argue. The bond that a mother develops with her child is truly remarkable. A mother becomes finely tuned to respond to each action and emotion of her child. Recent advances in our understanding of neuroscience suggest that maternal instinct and behavior may result from beneficial changes to her brain structure that result from pregnancy, coined as “maternal brain.”

State-of-the-art brain magnetic resonance imaging (MRI) has provided a glimpse of what maternal brain looks like. In MRI, the entire brain can be visualized and photographed. If images are taken at multiple time points, they can be compared to identify any changes that occur. For several mothers, researchers imaged the brain both before and 3-4 months after childbirth. An astonishing result was seen when comparing these two image sets: large increases in brain size were seen in the pre-frontal cortex, parietal lobes, and midbrain regions. There are two critical functions of these brain regions that relate to parenting. First, these regions recognize and process new sensory information that accompanies an infant including smell, touch, and vocalizations such as crying. Second, these regions tell your body how to respond to these stimuli.

Experts believe that these changes are healthy changes that may drive maternal behavior. In addition to the MRI scan, mothers were also asked if they thought they were good mothers. Increases in brain size correlated with positive maternal reactions to her child. That is, mothers who thought that they were a good mother and described a strong bond with their child had increased brain size.

In fact, developing a strong emotional tie to one’s child is not surprising. These brain regions also connect to and control the reward circuitry of the brain. The reward circuitry motivates behavior that your brain wants you to repeat. Usually, only extremely powerful stimuli such as drug addiction can change the structure of this brain region. The interactions of a mother and child are as strong and change the structure of this region so that a mother perceives her interactions as positive and continually repeats them. While it may be a stretch to say that a mother becomes addicted to her child, she is at the very least tuning her senses to detect even the smallest changes in her child’s behavior.

Hormones are thought to be the reason why the maternal brain increases in size. Hormones are small molecules that are found everywhere in the body and can initiate important events. In females, hormone levels rise to initiate birth when the infant is ready. These same hormones – estrogen, prolactin and oxytocin – also act on the brain. Here, they initiate brain growth and learning. Therefore, when a female gives birth it is natural and appropriate for her brain to grow and prepare her for motherhood.  These changes are healthy, new changes that don’t damage other brain regions.

The old saying “Mother knows best” may have scientific rationale, after all. 

CUAnschutz _h _clr

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