Keeping track of reality
Research provides new insight into why some of us are better than others at remembering what really happened
5 October 2011
A structural variation in a part of the brain may explain why some people are better than others at distinguishing real events from those they might have imagined or been told about, BBSRC-funded researchers have found.
Research into the fundamental biology of memory and learning can help us to understand how our brains work under normal circumstances. With that knowledge we can begin to learn about the ways in which health and well-being can be supported and maintained into later life.
The University of Cambridge scientists found that normal variation in a fold at the front of the brain called the paracingulate sulcus (or PCS) might explain why some people are better than others at accurately remembering details of previous events -such as whether they or another person said something, or whether the event was imagined or actually occurred. The research was published today, 05 October, in the Journal of Neuroscience.
This brain variation, which is present in roughly half of the normal population, is one of the last structural folds to develop before birth and for this reason varies greatly in size between individuals in the healthy population. The researchers discovered that adults whose MRI scans indicated an absence of the PCS were significantly less accurate on memory tasks than people with a prominent PCS on at least one side of the brain. Interestingly, all participants believed that they had a good memory despite one group's memories being clearly less reliable.
Dr Jon Simons from the University of Cambridge's Department of Experimental Psychology and Behavioural and Clinical Neuroscience Institute, who led the research, said: "As all those who took part were healthy adult volunteers with typical educational backgrounds and no reported history of cognitive difficulties, the memory differences we observed were quite striking. It is exciting to think that these individual differences in ability might have a basis in a simple brain folding variation.
"Additionally, this finding might tell us something about schizophrenia, in which hallucinations are often reported whereby, for example, someone hears a voice when nobody's there. Difficulty distinguishing real from imagined information might be an explanation for such hallucinations. For example, the person might imagine the voice but misattribute it as being real. PCS reductions have been reported in previous studies of schizophrenia, and our results are consistent with the idea that this structural variability might directly influence the functional capacity of surrounding brain areas and the cognitive abilities that they support."
For the study, the researchers recruited 53 healthy volunteers based on their brain scans which showed either a clear presence or absence of the PCS in the left or right brain hemisphere. Participants were presented either with well-known word-pairs like "Laurel and Hardy" or with the first word of a word-pair and a question mark ("Laurel and ?"). In the latter condition, participants were instructed to imagine the second word of the word-pair. Then, either they or the experimenter was instructed to read the word-pair out aloud. After a delay, a memory test was given where participants tried to remember whether they had seen or imagined the second word of each previously-encountered word-pair, or whether they or the experimenter had read the word-pair out aloud. Participants with absence of the PCS in both brain hemispheres scored significantly worse than the others at remembering both kinds of detail.
Notes to editors
- The paper 'A Specific Brain Structural Basis for Individual Differences in Reality Monitoring' will be published in the 05 October edition of Journal of Neuroscience.
- The work was funded by the BBSRC and a Medical Research Council (MRC) studentship to PhD student and first author Marie Buda. The Behavioural and Clinical Neuroscience Institute at the University of Cambridge is funded by a joint award from the MRC and the Wellcome Trust.
For almost 100 years the Medical Research Council has improved the health of people in the UK and around the world by supporting the highest quality science. The MRC invests in world-class scientists. It has produced 29 Nobel Prize winners and sustains a flourishing environment for internationally recognised research. The MRC focuses on making an impact and provides the financial muscle and scientific expertise behind medical breakthroughs, including one of the first antibiotics penicillin, the structure of DNA and the lethal link between smoking and cancer. Today MRC funded scientists tackle research into the major health challenges of the 21st century. www.mrc.ac.uk
About The Wellcome Trust
The Wellcome Trust is a global charitable foundation dedicated to achieving extraordinary improvements in human and animal health. It supports the brightest minds in biomedical research and the medical humanities. The Trust's breadth of support includes public engagement, education and the application of research to improve health. It is independent of both political and commercial interests. www.wellcome.ac.uk
BBSRC invests in world-class bioscience research and training on behalf of the UK public. Our aim is to further scientific knowledge, to promote economic growth, wealth and job creation and to improve quality of life in the UK and beyond.
Funded by Government, and with an annual budget of around £445M, we support research and training in universities and strategically funded institutes. BBSRC research and the people we fund are helping society to meet major challenges, including food security, green energy and healthier, longer lives. Our investments underpin important UK economic sectors, such as farming, food, industrial biotechnology and pharmaceuticals.
Genevieve Maul, Office of Communications, University of Cambridge
tel: +44 (0) 1223 765542
mob: +44 (0) 7774 017464