Direct Brain Stimulation Modulates Encoding States and Memory Performance in Humans

Youssef Ezzyat, James E. Kragel, John F. Burke, Deborah F. Levy, Anastasia Lyalenko, Paul Wanda, Logan O'Sullivan, Katherine B. Hurley, Stanislav Busygin, Isaac Pedisich, Michael R. Sperling, Gregory A. Worrell, Michal T. Kucewicz, Kathryn A. Davis, Timothy H. Lucas, Cory S. Inman, Bradley C. Lega, Barbara C. Jobst, Sameer A. Sheth, Kareem ZaghloulMichael J. Jutras, Joel M. Stein, Sandhitsu R. Das, Richard Gorniak, Daniel S. Rizzuto, Michael J. Kahana

Research output: Contribution to journalArticlepeer-review

145 Scopus citations


People often forget information because they fail to effectively encode it. Here, we test the hypothesis that targeted electrical stimulation can modulate neural encoding states and subsequent memory outcomes. Using recordings from neurosurgical epilepsy patients with intracranially implanted electrodes, we trained multivariate classifiers to discriminate spectral activity during learning that predicted remembering from forgetting, then decoded neural activity in later sessions in which we applied stimulation during learning. Stimulation increased encoding-state estimates and recall if delivered when the classifier indicated low encoding efficiency but had the reverse effect if stimulation was delivered when the classifier indicated high encoding efficiency. Higher encoding-state estimates from stimulation were associated with greater evidence of neural activity linked to contextual memory encoding. In identifying the conditions under which stimulation modulates memory, the data suggest strategies for therapeutically treating memory dysfunction.

Original languageEnglish (US)
Pages (from-to)1251-1258
Number of pages8
JournalCurrent Biology
Issue number9
StatePublished - May 8 2017


  • deep brain stimulation
  • epilepsy
  • episodic memory
  • free recall
  • intracranial EEG
  • local field potential
  • multivariate classification

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Agricultural and Biological Sciences


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