Mind
Recent research reveals that the brain activity of infants operates at a distinctly different rhythm compared to adults, indicating a perpetual state of learning in babies and a focus on knowledge retrieval in adults.
By Carissa Wong
The varying rhythms of brain activity in infants versus adults
GOODLUZ / Alamy
As infants engage with their surroundings, their brain activity shows a markedly slower rhythm than that of adults. This difference enables infants to continuously absorb and understand new information, fostering rapid learning of concepts.
Neuronal networks in the brain process sensory input. When a neuron receives significant signals from other neurons, it transmits these signals along, producing synchronized waves of electrical activity marked by alternating activation and silence among many neurons.
Brainwave patterns occur at diverse frequencies. Each brain region can display a mix of frequencies, leading to a substantial number of neurons aligning more closely with specific frequencies. For instance, previous research has demonstrated that the adult visual cortex tends to synchronize with frequencies around 10 hertz during visual tasks.
To ascertain if the same pattern holds true for infants, Moritz Köster and his research team from the University of Regensburg, Germany, studied 42 babies aged 8 months. The researchers recorded the infants’ brain activity through electrodes affixed to their scalps as they observed animated friendly cartoon monsters displayed on a screen for short durations during a 15-minute session.
The experimental setup took advantage of the fact that infants’ brainwaves tend to synchronize with rapidly changing images. Each cartoon monster was shown at various flicker rates, spanning frequencies from 2 to 30 hertz, allowing the researchers to measure how many neurons participated in the synchronization across the infantile visual cortex.
Results indicated that while the infants’ brains did synchronize with the flickering cartoons, the most robust synchronization occurred at 4 hertz, suggesting a higher engagement of neurons at this frequency compared to others. Notably, this 4-hertz rhythm persisted even as the brain adapted to other flickering frequencies, such as 15 hertz. Köster remarked, “The fascinating aspect is the consistent presence of the 4-hertz response, irrespective of the various stimulation frequencies.”
The significance of the 4-hertz signal lies within the theta frequency band, previously linked to the formation of new concepts. This suggests a potential mechanism through which infants learn from their visual experiences. Köster concluded, “The findings imply that infants are in an ongoing state of learning.”
Encouragingly, the study also revealed that the 4-hertz brainwaves spread to other neural circuits implicated in concept formation, suggesting these waves are instrumental in transferring visual data to regions involved in knowledge building.
In contrast, when the same experiments were conducted with seven adult participants, results aligned with earlier studies showing that adults’ visual systems are more responsive to a frequency of 10 hertz. This frequency continued to manifest even in the presence of various flickering rates, indicating a learned ability to filter out extraneous stimuli and focus on retrieving conceptual knowledge. Köster further explained this as sharpening the brain’s filtering capacity over time through experience.
Future research is warranted to explore whether exposing infants to visuals flickering at 4 hertz could boost their capacity to learn new concepts. Emily Jones of Birkbeck, University of London, has echoed this interest, indicating that the research team is eager to explore this possibility in ongoing studies led by Köster.
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