Babies Use Theta Rhythm the Same Way Adults Use to Understand Novel Events
Nine month old babies understand new or unexpected events with the help of theta rhythm just as it is done by adults for integration of novel events.
The experiments were done by
inviting parents to bring their 9 month old babies who were shown short picture
stories with either expected or unexpected physical or socila outcomes. . For
example, infants saw a man who was holding a pretzel. In the expected outcome
condition, he led the pretzel to his mouth. In the unexpected outcome
condition, to violate infants' expectations, he led the pretzel to his ear.
The electroencephalogram (EEG) of babies were tkane when they responded to images. The babies saw picture stories either at 4 Hz (theta) frequency or a 6 Hz (alpha) frequency. In theta condition, the events were shown at a flickering rate of 4 per second.
"The brain areas that are responsible for seeing, the visual cortex, synchronized their activity to the speed of the presented images. We were able to show that the brains of the babies, like in adults, respond to the rhythmic presentation of the events," according to Miriam Langeloh from the Max Planck Institute for Human Cognitive and Brain Sciences, Moritz Koster from the Freie Universitat Berlin and Stefanie Hohl form the University of Vienna.
In the next step, the research team looked at how the brain reacted for expected and unexpected outcomes. "Only the theta rhythm was sensitive to the unexpected compared to the expected actions. This shows us that the theta rhythm is responsible for the encoding of novel information in the infant brain. Importantly, in the alpha rhythm, which we looked at for comparison, there was no difference between expected and unexpected outcomes," they added.