Episodic memory allows us to mentally relive moments from the past, retrieving details such as what happened, where, and when. However, the way we recall these events can vary, highlighting different aspects of the experience. Studies indicate that cued recollection simultaneously activates two essential brain networks: the DMN (Default Mode Network) and the FPCN (Frontoparietal Control Network). An investigation led by Matteo Frisoni analysed whether different memory dimensions – details of objects and characters, spatial layouts, temporal sequences, and verbal dialogues – are processed in specialized sub-regions within these networks and whether this differentiation influences recall performance. The results showed that the FPCN exhibited common activation for all memory dimensions, while the DMN revealed more pronounced specialization, especially in its posterior regions. Additionally, it was found that greater functional specificity within these networks was associated with better memory performance. The research also revealed an asymmetry in the DMN, with greater activation in the left hemisphere for all dimensions except the temporal, while the FPCN maintained balanced activation between hemispheres. This study offers a new perspective on how the brain organizes and optimizes our ability to recall past experiences. This study was supported by the BIAL Foundation, in the scope of the research project 384/20 - Schema-based temporal memory in parietal cortex (SCHETEMP), and published in the journal NeuroImage, in the article Specialization for different memory dimensions in brain activity evoked by cued recollection - ScienceDirect.
ABSTRACT
Cued recollection involves the retrieval of different features of the encoded event. Previous research has shown that the recollection of complex events jointly recruits the Default Mode and the Frontoparietal Control networks, but the degree to which activity within these networks varies as a function of the particular memory dimension (e.g., the “when-what-where” information) remains largely unknown. In the present functional Magnetic Resonance Imaging (fMRI) study, human participants retrieved specific information about a previously encoded TV show to assess the veracity of detailed sentences along four memory dimensions (i.e., object and character details, spatial layouts, temporal sequences, verbal dialogues). A common activity for all dimensions was observed in a left-lateralized network of regions that largely overlaps with the Frontoparietal Control Network (FPCN), including the lateral prefrontal, lateral superior parietal, and lateral temporal cortex. Instead, a larger degree of specialization for different memory dimensions was observed within the Default Mode Network (DMN), particularly in its posterior nodes. Dimension-related specificity in both networks was associated with memory performance across subjects. Finally, a clear leftward asymmetry was observed in the DMN for all dimensions except for the temporal one, whereas the FPCN showed a bilateral activation across dimensions. The present results generally support the view that specific memory information is processed by a mosaic of regions within large portions of the associative cortex involved in higher-order mnemonic functions.
