It has long been known that we struggle to remember our childhood - especially before the age of three.
Researchers believe they now know why.
They claim that as we become older, the growth of new brain cells effectively overwrites existing cells, erasing the early memories.
'Infantile amnesia refers the absence of memories for events that occurred in our earliest years—most people typically don’t remember much of what happened when they were only 2 or 3 years-old,' said Katherine Akers, who led the study at the Neurobiology Laboratory at the Hospital for Sick Children in Toronto.
'But this doesn’t seem to be because children at this stage can’t make memories—when our daughter, for instance, was 3 years old she would enthusiastically recount in details trips to the zoo to see grandparents and so on.
'But she is now 5 and has no recollection of these events - these memories are rapidly forgotten.'
Since the hippocampus is important for memory, there have been several studies examining how new neurons might contribute to forming new memories.
The typical result is that reducing levels of neurogenesis impairs the formation of new memories.
But as new neurons integrate into the hippocampus, they may also impact existing memories, the researchers believed.
In particular, as new neurons integrate they necessarily remodel hippocampal circuits, and this remodeling may lead to degradation of information (memories) stored in those circuits.
In a new paper the tested this idea by artificially elevating levels of neurogenesis after learning in adult mice.
'We speculated that these high levels of hippocampal neurogenesis are essentially incompatible with stable memory storage—while infant mice (and human infants) are able to make memories, high levels of neurogenesis lead to the ‘overwriting’ of this information and forgetting.
'In our paper we provided evidence for this idea by showing that reducing neurogenesis in infant mice led to the relative preservation of memories that otherwise would have been forgotten.'
Buy that's quite funny cos even as adults we're still developing new brain cells how come we still recall events of the past.
ReplyDeleteI think there's more to this madam Katherine Akers