Infantile amnesia is caused by the underdevelopment of the infant's brain. That is why adults could not recollect early episodic memories as they rapidly forget events that occurred in their early years.
But these early memories play a crucial role in adult behavior and may predispose them to psychopathologies even though these early memories are inaccessible, according to The Journal of Neuroscience.
It is not yet clear how a brain rapidly forgets or how it was not able to form long-term memories. But even so, a new study suggests that the brain's memory center, the hippocampus, is already active as early as three months.
Brain Imaging Shows Hippocampus Already Active At Very Young Age
The hippocampus is a part of the brain that is located in the temporal lobe and plays a crucial role in encoding memories. However, it cannot store long-term memories during the first three or four years of a human's life, a phenomenon called infantile amnesia.
But the scientists at Yale University found that the hippocampus is already active as early as three months, Science Daily reported. It can already recognize and learn patterns, which is crucial for encoding memory.
Yale psychology professor Nick Turk-Browne said that the fundamental mystery of human nature is that humans remember almost nothing from birth to early childhood and yet events during those times are crucial information.
The team used a new functional magnetic resonance imaging (fMRI) technology to observe what happens with the hippocampus of 17 babies aged three months to two years old as they were presented with two sets of images on a screen.
The first image contains patterns that facilitate learning, while the second one is arranged in a random order that could not be learned. They were shown the two sets of images repeatedly.
The team found that the hippocampus of the babies responded more strongly to the first photo that showed structures or patterns that can be learned than the second image set.
The Brain Searches Patterns to Understand the Environment
Turk-Browne said that they were able to observe the active hippocampus because as babies gain experience in the world, they learn patterns that would help them understand and predict their environment.
According to Big News Network, this happens even though babies cannot permanently store each experience at a very young age. It can also happen to adults with amnesia.
Learning basic knowledge, such as patterns of sounds, is more important for a baby than remembering specific details, like an event when a specific word is uttered by their caregiver. This explains why the hippocampus of a three-month-old may be active even if it cannot store long-term memories as of yet.
The team noted that the size of the hippocampus doubles within the first two years of life. Eventually, it will develop and form connections that are necessary to store episodic memories.
The study, entitled "Evidence of hippocampal learning in human infants," is published in the journal Current Biology.
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