Changes in Brain Wave Frequency Help Retain Information

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Scientists have discovered that the hippocampus and the prefrontal cortex use different brain waves to communicate with each other, according to a new study from the Massachusetts Institute of Technology.

Previously, scientists believed that brain waves were just a byproduct of neuron activity. However, a new study suggests that the brain uses these waves to help form new memories.

Researchers studied the brain’s activity during explicit memory formation. Animals were shown pairs of images and learned which images went together by trial and error, with correct responses prompting a reward.

During the task, the animals’ brain waves differed based on whether they provided a correct or incorrect response. When they guessed correctly, the waves occurred in the beta frequency. When they guessed incorrectly, the waves occurred in the theta frequency.

The difference in frequencies suggests that the higher beta frequency helps reinforce the correct answer while the lower theta frequency represses the incorrect information. In this way, the waves help the brain learn new information.

“When the animal guesses correctly, the brain hums at the correct answer note, and that frequency reinforces the strengthening of connections,” said Earl Miller, PhD, of MIT. “When the animal guesses incorrectly, the ‘wrong’ buzzer buzzes, and that frequency is what weakens connections, so it’s basically telling the brain to forget about what it just did.”

Based on these results, the researchers have begun a new study where they hope to speed up learning. In the study, they will use electrical stimulation that oscillates at beta or theta frequencies based on whether the correct answer is given.

Brain wave
Changes in Brain Wave Frequency Help Retain Information

Our brains generate a constant hum of activity: As neurons fire, they produce brain waves that oscillate at different frequencies. Long thought to be merely a byproduct of neuron activity, recent studies suggest that these waves may play a critical role in communication between different parts of the brain.

A new study from MIT neuroscientists adds to that evidence. The researchers found that two brain regions that are key to learning — the hippocampus and the prefrontal cortex — use two different brain-wave frequencies to communicate as the brain learns to associate unrelated objects. Whenever the brain correctly links the objects, the waves oscillate at a higher frequency, called “beta,” and when the guess is incorrect, the waves oscillate at a lower “theta” frequency.

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