Coding of episodic memory in the human hippocampus
Abstract
Neurocomputational models hold that episodic memories are represented by sparse, stimulus-specific neural codes. In tests of episodic memory, single-unit recording studies of the human hippocampus have found neurons that operate as general novelty detectors or general familiarity detectors. Here, we investigated whether neurons can be found that sparsely code some recently studied items and not others. In the left hippocampus, but not the amygdala, we found that small fractions of neurons exhibited strong responses to specific repeated words. The remaining large fractions of neurons exhibited a concurrent reduction in firing rates relative to novel words. Both findings are consistent with predictions made by neurocomputational models of how episodic memory is coded in the hippocampus.
- Publication:
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Proceedings of the National Academy of Science
- Pub Date:
- January 2018
- DOI:
- 10.1073/pnas.1716443115
- Bibcode:
- 2018PNAS..115.1093W