Encoding activity predicts distinct recognition signals during working and long-term memory in the human hippocampus
- 1University of California San Diego
Abstract
Neurocomputational models predict that episodic memories are represented by sparse, pattern-separated hippocampal codes. Recognition within working memory capacity may instead rely on overlapping cortical codes. We analyzed human intracranial microwire recordings during a continuous recognition task to test whether retrieval demand and spiking activity at encoding determine which neural signal is expressed. We show that relative increases in firing from pre-stimulus to post-stimulus onset at encoding predicted an item-specific signal that was present only in the hippocampus and only during long-term memory retrieval of remembered items. In contrast, consistently elevated firing predicted a generic signal that distinguished remembered from novel items, was present in the hippocampus during both working and long-term memory retrieval, and extended to the anterior cingulate and prefrontal cortices during working memory. These findings are consistent with a new theory that distinguishes working memory from long-term memory in terms of the neural coding scheme accessed at retrieval.
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BibTeX
@misc{tallman2026encoding,
title = {{Encoding activity predicts distinct recognition signals during working and long-term memory in the human hippocampus}},
author = {C. W. Tallman and J. T. Wixted and P. N. Steinmetz},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.21.759719},
url = {https://www.biorxiv.org/content/10.64898/2026.10.21.759719v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Encoding activity predicts distinct recognition signals during working and long-term memory in the human hippocampus
AU - C. W. Tallman
AU - J. T. Wixted
AU - P. N. Steinmetz
PY - 2026
DA - 2026/10/21
PB - bioRxiv
DO - 10.64898/2026.10.21.759719
UR - https://www.biorxiv.org/content/10.64898/2026.10.21.759719v1
AB - Neurocomputational models predict that episodic memories are represented by sparse, pattern-separated hippocampal codes. Recognition within working memory capacity may instead rely on overlapping cortical codes. We analyzed human intracranial microwire recordings during a continuous recognition task to test whether retrieval demand and spiking activity at encoding determine which neural signal is expressed. We show that relative increases in firing from pre-stimulus to post-stimulus onset at encoding predicted an item-specific signal that was present only in the hippocampus and only during long-term memory retrieval of remembered items. In contrast, consistently elevated firing predicted a generic signal that distinguished remembered from novel items, was present in the hippocampus during both working and long-term memory retrieval, and extended to the anterior cingulate and prefrontal cortices during working memory. These findings are consistent with a new theory that distinguishes working memory from long-term memory in terms of the neural coding scheme accessed at retrieval.
ER -