The aim of the study was to link individual differences in ways of creating memories with the brain’s microstructure. To achieve this, the scientific team scanned 48 volunteers using structural magnetic resonance imaging (MRI). Specifically, a new technique called Diffusion Tensor Imaging (DTI) was used to study the structure of the white matter (mainly the axonal structure) of these volunteers.

Before participants were scanned, they took a memory test that consisted in remembering lists of words that they were subsequently asked to recall. A list could consist of: sofa, table, sit, desk, rocking chair, legs, stool, wood, etc. (14 words per list). Immediately after hearing the list of words, participants had to write down all of the ones that they recalled. Once they had heard all the lists, participants were given a questionnaire in which words that had been heard in the lists (for example, “sofa”) were presented with totally new words (for example, “shirt”) and with words that had not been presented but that were semantically related to the contents of the list (for example, “chair”).

The participant’s task was to state whether or not the word had appeared during the experiment and the level of their memory (if they remembered the word well and accurately or not). Surprisingly, in 75% of cases, participants said that words of the “chair” type (false memories) had appeared in the list. In other cases, participants stated that they remembered having heard a word that had never been presented. In fact, this effect is highly robust (Deese-Roediger-McDermott paradigm, DRM) and indicates the malleability of our memory, as well as the fact that memories are constructed progressively and that we are susceptible to memory distortions or false memories.

According to the study, the tendency to generate true and false memories is associated with individual differences in white matter. True memories are linked to a bundle of white matter fibres (cerebral axons that connect areas of the cerebral cortex) that connects the hippocampus and the parahippocampus. These structures have been associated with recall and memory storage. In contrast, the tendency to generate false memories is related to another bundle of white matter fibres (the superior longitudinal fasciculus) that connects structures in the frontoparietal cortex, which have been linked to false memories in other magnetic resonance studies.

Reference: Fuentemilla, L.; Camara, E.; Müntem. T. F.; Kramer, U. M.; Cunillera, T.; Marco-Pallares, J.; Tempelmann, C.; Rodriguez-Fornells, A. “Individual Differences in True and False Memory Retrieval are related to White Matter Brain Microstructure”.