News articles

Hippocampal subfield size predicts the precision of memory recall

11 July 2014

The hippocampus is a brain structure crucial for forming and recollecting memories of our personal experiences, which are known as episodic memories. It was thought that each memory is processed by a completely separate set of neurons within a part of the hippocampus called CA3.

Hippocampus subfields (CA3)

However, using functional MRI brain scanning, researchers at UCL Institute of Neurology funded by the Wellcome Trust,  have found that CA3 "memory traces" can in fact overlap when the memories are very similar to one another, leading to the experience of memory confusion or interference.

Intriguingly, the researchers also found that variations in the physical size of CA3 predicted differences in the extent of memory trace overlap and memory confusion across the research participants.

A larger CA3 may contain more neurons or more connections between neurons, which could allow greater physical separation of the different memory traces.

Dr Martin Chadwick, Lead Author

Our results may help to explain why we sometimes find it difficult to differentiate between similar past memories, and why some people are better at doing this than others.

Professor Eleanor Maguire, Senior author

Further information:

Chadwick, M.J., Bonnici, H.M., Maguire, E.A. CA3 size predicts the precision of memory recall. PNAS. Available online 7th July 2014. doi:10.1073/pnas.1319641111

BBC news

Image: figure showing the subfields of the hippocampus, with CA3 – the topic of the paper – shown in red.

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