Brain scientists may have a new window into an unborn child's mind. Researchers have shown that functional magnetic resonance imaging (fMRI)--an imaging technology that has sprouted only in the past decade--can detect changes in fetal brain activity in response to sounds from outside the womb. The finding, published in the 21 August Lancet, opens up new possibilities for studying brain development.
Brain activity in unborn children has been hard to study, and neonatologists have been forced to rely on indirect measures--such as heart rate--for clues to neural activity. Within the last decade, however, new technologies have given researchers a more direct look at the workings of adult brains. Among them is fMRI, a collection of techniques that uses magnetic fields and sensitive detectors to spot active brain areas by telltale increases in blood oxygen. Researchers have used fMRI to probe people's neural responses to a wide range of stimuli, from pictures to questions.
Now, physicist Penny Gowland and colleagues at the University of Nottingham in England have used the technique to see how unborn children respond to their mothers' voices. The researchers asked four pregnant women to record a nursery rhyme, then scanned their abdomens while the poem was replayed through a loudspeaker aimed at each woman's belly, with 15 seconds of audio stimulation alternating with 15 seconds of silence. In 2 cases, the researchers were able to capture "significant" activation of the child's temporal lobes, coinciding with the times they were being exposed to their mothers' voices. The study represents "a completely new application of fMRI," says Gowland, and demonstrates that fetal brain activity related to outside sounds can be more directly measured.
The work is "a real technical feat," says cognitive neuroscientist James Haxby, chief of the Section on Functional Brain Imaging at the National Institute of Mental Health. He believes "it's just a matter of years before sensitivity is vastly improved," leading to more detailed studies of brain development.