Abstract
The medial temporal lobe is critical for both spatial navigation and memory. Although single neurons in the medial temporal lobe activate to represent locations in the environment during navigation, how this spatial tuning relates to memory for events involving those locations remains unclear. We examined memory-related changes in spatial tuning by recording single-neuron activity from neurosurgical patients performing a virtual-reality object–location memory task. We identified ‘memory-trace cells’ with activity that was spatially tuned to the retrieved location of the specific object that participants were cued to remember. Memory-trace cells in the entorhinal cortex, in particular, encoded discriminable representations of different memories through a memory-specific rate code. These findings indicate that single neurons in the human entorhinal cortex change their spatial tuning to target relevant memories for retrieval.
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Data availability
The data that support the findings of this study are available on reasonable request from the corresponding author. The data are not publicly available because they could compromise research participant privacy and consent.
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Acknowledgements
We are grateful to the patients for participating in our study. This work was supported by NIH grants R01-MH104606 (to J.J.) and S10-OD018211 (to C.S.), NSF grants BCS-1724243 and BCS-1848465 (to J.J.), and NSF Graduate Research Fellowship DGE 16-44869 (to S.E.Q.). We thank Andrew Watrous (University of Texas, Austin), Melina Tsitsiklis (Columbia University), Ida Momennejad (Columbia University), Mariam Aly (Columbia University), Nicole Long (University of Virginia), and Niko Kriegeskorte (Columbia University) for helpful comments and suggestions.
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J.J. conceived the experiment; R.E.G., J.T.W., B.L., A.S., C.W., S.A.S., and G.M.M. performed surgical procedures; S.E.Q., J.M., M.R.S., C.S., E.H.S., J.-J.L., and C.S.I. performed data collection and recording; J.M.S. processed neuroimaging data; S.E.Q. analyzed the data; and S.E.Q. and J.J. wrote the manuscript.
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Supplementary Figures 1–14 and Supplementary Tables 1 and 2.
Supplementary Video 1
This video depicts the task instructions that participants are given at the beginning of a session, followed by two encoding trials and one retrieval trial for an object.
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Qasim, S.E., Miller, J., Inman, C.S. et al. Memory retrieval modulates spatial tuning of single neurons in the human entorhinal cortex. Nat Neurosci 22, 2078–2086 (2019). https://doi.org/10.1038/s41593-019-0523-z
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DOI: https://doi.org/10.1038/s41593-019-0523-z
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