Infant brains reflect moms' depression.
Preliminary evidence suggests that the distressed behavior of infants born to depressed mothers occurs in conjunction with electrical-activity changes in the emotion-regulating regions of the babies' brains.
"This may be the first study to show that maternal psychopathology affects brain activity that mediates infant behavior, says psychologist and research director Geraldine Dawson of the University of Washington in Seattle. She described the results last week at a seminar held at the National Institute of Mental Health in Bethesda, Md.
Dawson's group drew inspiration from psychologist Nathan A. Fox of the University of Maryland in College Park, who found that electrical activity across the surface of a healthy infant's left frontal lobe, as measured by electrodes on the scalp, increases during positive emotions, whereas electrical activity across the right frontal lobe increases during negative emotions (SN: 9/9/89, p. 175). Other researchers detected amplified right-frontal activity among depressed college students, even when their moods temporarily lifted.
The Seattle investigators studied 34 infants between 11 and 17 months of age. All were born to low-income teenage mothers, most of whom were Caucasian. Self-reports indicated that half the mothers were clinically depressed during the week before the experiment, with symptoms that interfered greatly with daily functioning.
Dawson's team monitored electrical activity in the infants' brains during a series of laboratory experiences. Each baby first watched a video screen displaying cascading bubbles, providing investigators with a resting measure of brain electrical activity. Each mother then used a cardboard mask to play peek-a-boo with her infant. Next, a stranger entered the room, moved close to the baby while maintaining a neutral facial expression, and walked away. Finally, the mother briefly left the room and returned.
Infants of nondepressed mothers smiled and giggled during peek-a-boo, gazed steadily at their mothers, glanced intermittently and uncertainly at the stranger, and cried when their mothers left. Infants of depressed mothers rarely smiled at any time, usually looked away from both their mothers and the stranger, and showed little distress when mothers departed.
The reasons for the unusual responses of infants in the latter group remain unclear. Dawson suggests these babies may imitate their mothers' withdrawn demeanor or retreat from social interactions out of frustration and anger at dealing with a nonresponsive mother. Genetic transmission of depression may partially influence their behavior, she adds.
Whatever the case, electrical-activity changes in infants' brains corresponded with the onset of different behaviors and emotional displays during the experiment, Dawson says. Infants of nondepressed mothers displayed increased electrical activity in the left frontal lobe during pleasant peek-a-boo sessions, and an electrical surge in the right frontal lobe during the upsetting exit of their mothers. Among depressed mothers' infants, electrical activity in the right frontal lobe was greater at the start of the experiment and increased even more during peek-a-boo sessions, while left frontal activity peaked when the mothers left the room.
If a depressed mother begins to feel better and her interactions with her baby brighten, the infant's pattern of brain activity may change as well, Dawson speculates. She plans to test this prediction in an upcoming study.
Dawson also hopes to monitor the progress of six infants from her current study who displayed extremely high activation of the right frontal lobe at rest. Noting that five of these infants had depressed mothers, she asserts that this group may show a marked vulnerability to depression as they get older.
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|Date:||Nov 17, 1990|
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