Meiosis: A PRDM9 Guide to the Hotspots of Recombination

This new study [14] allows us to think about a host of further questions. For example, are memories of the same events stored in a similar way by different people, at least to the degree to which the content of their memories are shared? For this, the patterns of brain activation do not need to be equal, but the amount of information stored in different structures and their relative contribution to memoryassociated patterns might be similar, as was indeed found by Chadwick et al. [14]. Similarity in activation patterns can even carry quite specific information: response patterns in the data of a group of subjects can be used to differentiate cognitive tasks in a separate individual [15,16]. Combining within-subject and between-subject classifiers might thus make it possible to differentiate the response patterns representing aspects of memories that are shared across people from those that differ, getting at the neural correlates of inter-individual differences in memory content. Progress in neuroimaging techniques is followed with interest by the public, as neuroscience methods have started to be used to address legal questions. The judge of a court in India directly referred to a forensic analysis of electroencephalography data in his written opinion of a murder trial, and similar brain data analysis methods have been admitted in legal proceedings in the USA (see [17] for a recent review). Commercial applications have started to spring up, such as assessing the attractiveness of products (Neuromarketing) or quantifying the effect that movies might have on people’s perception (Neurocinema). Further extensions of the method are to be expected: if what has been achieved for vision (reading observed letters from early visual cortex activity [18]) becomes possible for memory, then maybe one day we could be able to read the contents of a person’s memory. It might be possible to change stored memories too: conditioned fear responses can be erased with purely behavioural methods [19]. Combining reading and modification of memories brings closer a host of science-fiction scenarios, as for example in novels such as ‘‘We can remember it for you wholesale’’ by Philip K. Dick (adapted into the movie ‘‘Total Recall’’) and countless other Hollywood movies, for example, Eternal Sunshine of the Spotless Mind, The Manchurian Candidate and Vanilla Sky. All these applications and fictional scenarios are of course seen with very cautious reserve by scientists, and rightly so: To convince researchers, a scientific method needs only to yield results reaching statistical significance (that is, beat chance). When considering the application of a method in everyday life, however, one must consider the consequence of any deviation from perfect performance. Discussion of ethical, sociological and legal aspects of the application of multivariate analyses promise a number of interesting debates.