U. OREGON (US) — The blunted way a depressed mother responds to her baby’s cry can negatively affect the child’s development and have long-lasting repercussions on the mother-infant relationship.
Brain scans of depressed women show reactions to cries are much more muted that the robust brain activity in non-depressed mothers.
The study, published online in advance of publication in the journal Social Cognitive and Affective Neuroscience, scrutinized 22 women using functional magnetic resonance imaging (fMRI) to see how brain activity of depressed women responded to recordings of crying infants, either their own or someone else’s.
Researchers considered both group differences between women with chronic histories of depression and those with no clinical diagnoses, and more subtle variations in the women’s brain activity related to current
levels of depressive symptoms. All were first time mothers whose babies were 18 months old.
“It looks as though depressed mothers are not responding in a more negative way than non-depressed mothers, which has been one hypothesis,” says Heidemarie K. Laurent, assistant professor at the University of Wyoming, who led the study as a postdoctoral researcher with Jennifer C. Ablow, professor of psychology at the University of Oregon.
“What we saw was really more of a lack of responding in a positive way.”
As a group, brain responses in non-depressed mothers responding to the sound of their own babies’ cries were seen on both sides of the brain’s lateral paralimbic areas and core limbic sub-cortical regions including the striatum, thalamus and midbrain; depressed mothers showed no unique response to their babies.
Non-depressed mothers activated much more strongly than depressed mothers in a subcortical cluster involving the striatum—specifically the caudate and nucleus accumbens—and the medial thalamus. These areas are closelyassociated with the processing of rewards and motivation.
“In this context it was interesting to see that the non-depressed mothers were able to respond to this cry sound as a positive cue,” Laurent says. “Their response was consistent with wanting to approach their infants. Depressed mothers were really lacking in that response. ”
In a separate comparison, mothers who self-reported that they were more depressed at the time of their fMRI sessions displayed diminished prefrontal brain activity, particularly in the anterior cingulate cortex, when hearing their own baby’s cries.
This brain region, Laurent says, is associated with the abilities to evaluate information and to plan and regulate a response to emotional cues.
The important message, is that depression can exert long-lasting effects on mother-infant relationships by blunting the mother’s response to her infant’s emotional cues.
“A mother who is able to process and act upon relevant information will have more sensitive interactions with her infant, which, in turn, will allow the infant to develop its own regulation capacities,” Ablow says.
“Some mothers are unable to respond optimally to their infant’s emotional cues. A mother’s emotional response requires a coordination of multiple cortical and sub-cortical systems of the brain. How that plays out has not been well known.”
The findings may suggest new implications for treating depression symptoms in mothers, Laurent says. “Some of these prefrontal problems may be changed more easily by addressing current symptoms, but there may be deeper, longer-lasting deficits at the motivational levels of the brain that will take more time to overcome.”
We regard the findings as a “jumping-off point” to better understand the neurobiology of the mothering brain, says Ablow.
“In our next study, we plan to follow women from the prenatal period through their first-year of motherhood to get a fuller picture of how these brain responses shape mother-infant relationships during a critical period of their babies’ development.”
The research was funded by the National Science Foundation and the National Institute of Mental Health.
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