Canadian researchers have found that the formation of new neurons in the region of the brain that helps in learning and remembering, the hippocampus, could lead to forgetting of old memories due to reorganization of existing brain circuits.
Drs. Paul Frankland and Sheena Josselyn, both from the Hospital for Sick Children in Toronto, argue this reorganization could have the positive effect of clearing old memories, reducing interference and thereby increasing capacity for new learning. These results were presented at the 2013 Canadian Neuroscience Meeting, the annual meeting of the Canadian Association for Neuroscience - Association Canadienne des Neurosciences (CAN-ACN).
Researchers have long known of the phenomenon of infantile amnesia: This refers to the absence of long-term memory of events occurring within the first 2-3 years of life, and little long-term memories for events occurring until about 7 years of age. Studies have shown that though young children can remember events in the short term, these memories do not persist. This new study by Frankland and Josselyn shows that this amnesia is associated with high levels of new neuron production - a process called neurogenesis - in the hippocampus, and that more permanent memory formation is associated with a reduction in neurogenesis.
Dr. Frankland concludes: " Why infantile amnesia exists has long been a mystery. We think our new studies begin to explain why we have no memories from our earliest years."