The hippocampus may help us to visualise the future as well as remember the past.

The hippocampus, a small structure deep in the brain supposedly shaped like a seahorse, is needed for the creation of new memories. It is key to episodic memory – recall of events and personal experiences – and the creation of internal spatial representations of the outside world. Intriguingly, Senior Research Fellow Eleanor Maguire and her team at the Wellcome Trust Centre for Neuroimaging at University College London have found that it also helps us to imagine future and fictitious experiences.

People with damage to the hippocampus typically have problems creating new memories and suffer amnesia. But pinpointing the exact role of the hippocampus in episodic memory is difficult as each person's experience is so different.

To address this issue, Dr Maguire, Demis Hassabis and colleagues tested the ability of people with selective hippocampal damage to create and visualise in their mind's eye new fictitious experiences. Four out of five patients found it hard to picture and describe the imagined experiences, even though they could conjure up images of elements associated with the events, such as objects and people. The amnesic patients struggled to picture an experience as a spatially coherent whole.

The hippocampus thus seems to play a crucial role in creating the spatial context or environmental setting that provides the backdrop for remembering what has happened to us in the past – and also, it now seems, for imagining what might happen to us in the future.

Image: Dr Eleanor Maguire

External link

• Hassabis D et al. Patients with hippocampal amnesia cannot imagine new experiences. Proc Natl Acad Sci USA 2007;104(5):1726–31.