RT Journal Article
SR Electronic
T1 A preserved neural code for temporal order between memory formation and recall in the human medial temporal lobe
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2024.10.12.618011
DO 10.1101/2024.10.12.618011
A1 Khazali, Mohammad Farhan
A1 Brandt, Armin
A1 Reinacher, Peter C.
A1 Kahana, Michael
A1 Jacobs, Joshua
A1 Schulze-Bonhage, Andreas
A1 Kunz, Lukas
YR 2024
UL http://biorxiv.org/content/early/2024/10/12/2024.10.12.618011.abstract
AB Temporal memory enables us to remember the temporal order of events happening in our life. The human medial temporal lobe (MTL) appears to contain neural representations supporting temporal memory formation, but the cellular mechanisms that preserve temporal order information for recall are largely unknown. Here, we examined whether human MTL neuronal activity represents the temporal position of events during memory formation and recall, using invasive single and multi-unit recordings in human epilepsy patients (n = 19). Participants freely navigated a virtual environment in order to explore and remember locations and temporal positions of objects. During each exploration period, they sequentially encountered two or three different objects, placed in different locations. This allowed us to examine single- and multi-unit neuronal firing rates (FR) as a function of the temporal position the objects were presented in. We found that a significant number of multi-units and single-units in various MTL regions including the hippocampus showed selectivity to the temporal position of objects during the exploration period. During recall, patients were asked to indicate which one of two objects from the same trial was found latter. Neural firing rates during recall showed a selectivity supporting recall of temporal positions. Interestingly, most of the selective single-units that stayed selective during encoding and recall preserved their temporal position preference. Our results thus suggest that neuronal activity in the human MTL contains a preserved neural code for temporal order in memory formation and recall.Competing Interest StatementThe authors have declared no competing interest.