Contextually Mediated Spontaneous Retrieval Is Specific to the Hippocampus

Nicole M. Long, Michael R. Sperling, Gregory Alan Worrell, Kathryn A. Davis, Robert E. Gross, Bradley C. Lega, Barbara C. Jobst, Sameer A. Sheth, Kareem Zaghloul, Joel M. Stein, Michael J. Kahana

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Although it is now well established that the hippocampus supports memory encoding [1, 2], little is known about hippocampal activity during spontaneous memory retrieval. Recent intracranial electroencephalographic (iEEG) work has shown that hippocampal activity during encoding predicts subsequent temporal organization of memories [3], supporting a role in contextual binding. It is an open question, however, whether the hippocampus similarly supports contextually mediated processes during retrieval. Here, we analyzed iEEG recordings obtained from 215 epilepsy patients as they performed a free recall task. To identify neural activity specifically associated with contextual retrieval, we compared correct recalls, intrusions (incorrect recall of either items from prior lists or items not previously studied), and deliberations (matched periods during recall when no items came to mind). Neural signals that differentiate correct recalls from both other retrieval classes reflect contextual retrieval, as correct recalls alone arise from the correct context. We found that in the hippocampus, high-frequency activity (HFA, 44–100 Hz), a proxy for neural activation [4], was greater prior to correct recalls relative to the other retrieval classes, with no differentiation between intrusions and deliberations. This pattern was not observed in other memory-related cortical regions, including DLPFC, thus supporting a specific hippocampal contribution to contextually mediated memory retrieval.

Original languageEnglish (US)
Pages (from-to)1074-1079
Number of pages6
JournalCurrent Biology
Volume27
Issue number7
DOIs
StatePublished - Apr 3 2017

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Hippocampus
Data storage equipment
hippocampus
epilepsy
Proxy
Epilepsy
Chemical activation

Keywords

  • context
  • episodic memory
  • free recall
  • iEEG
  • retrieval

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Cite this

Long, N. M., Sperling, M. R., Worrell, G. A., Davis, K. A., Gross, R. E., Lega, B. C., ... Kahana, M. J. (2017). Contextually Mediated Spontaneous Retrieval Is Specific to the Hippocampus. Current Biology, 27(7), 1074-1079. https://doi.org/10.1016/j.cub.2017.02.054

Contextually Mediated Spontaneous Retrieval Is Specific to the Hippocampus. / Long, Nicole M.; Sperling, Michael R.; Worrell, Gregory Alan; Davis, Kathryn A.; Gross, Robert E.; Lega, Bradley C.; Jobst, Barbara C.; Sheth, Sameer A.; Zaghloul, Kareem; Stein, Joel M.; Kahana, Michael J.

In: Current Biology, Vol. 27, No. 7, 03.04.2017, p. 1074-1079.

Research output: Contribution to journalArticle

Long, NM, Sperling, MR, Worrell, GA, Davis, KA, Gross, RE, Lega, BC, Jobst, BC, Sheth, SA, Zaghloul, K, Stein, JM & Kahana, MJ 2017, 'Contextually Mediated Spontaneous Retrieval Is Specific to the Hippocampus', Current Biology, vol. 27, no. 7, pp. 1074-1079. https://doi.org/10.1016/j.cub.2017.02.054
Long, Nicole M. ; Sperling, Michael R. ; Worrell, Gregory Alan ; Davis, Kathryn A. ; Gross, Robert E. ; Lega, Bradley C. ; Jobst, Barbara C. ; Sheth, Sameer A. ; Zaghloul, Kareem ; Stein, Joel M. ; Kahana, Michael J. / Contextually Mediated Spontaneous Retrieval Is Specific to the Hippocampus. In: Current Biology. 2017 ; Vol. 27, No. 7. pp. 1074-1079.
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