Theta-burst microstimulation in the human entorhinal area improves memory specificity

Ali S Titiz; Michael R H Hill; Emily A Mankin; Zahra M Aghajan; Dawn Eliashiv; Natalia Tchemodanov; Uri Maoz; John Stern; Michelle E Tran; Peter Schuette; Eric Behnke; Nanthia A Suthana; Itzhak Fried

doi:10.7554/eLife.29515

eLife (Oct 2017)

Theta-burst microstimulation in the human entorhinal area improves memory specificity

Ali S Titiz,
Michael R H Hill,
Emily A Mankin,
Zahra M Aghajan,
Dawn Eliashiv,
Natalia Tchemodanov,
Uri Maoz,
John Stern,
Michelle E Tran,
Peter Schuette,
Eric Behnke,
Nanthia A Suthana,
Itzhak Fried

Affiliations

Ali S Titiz: Department of Neurosurgery, University of California, Los Angeles, United States
Michael R H Hill: Department of Neurosurgery, University of California, Los Angeles, United States; California Institute of Technology, Pasadena, United States
Emily A Mankin: ORCiD; Department of Neurosurgery, University of California, Los Angeles, United States
Zahra M Aghajan: ORCiD; Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, United States
Dawn Eliashiv: Department of Neurology, University of California, Los Angeles, United States
Natalia Tchemodanov: Department of Neurosurgery, University of California, Los Angeles, United States
Uri Maoz: Department of Neurosurgery, University of California, Los Angeles, United States; California Institute of Technology, Pasadena, United States; Department of Psychology, University of California, Los Angeles, United States
John Stern: Department of Neurology, University of California, Los Angeles, United States
Michelle E Tran: Department of Neurosurgery, University of California, Los Angeles, United States
Peter Schuette: Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, United States
Eric Behnke: Department of Neurosurgery, University of California, Los Angeles, United States
Nanthia A Suthana: Department of Neurosurgery, University of California, Los Angeles, United States; Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, United States; Department of Psychology, University of California, Los Angeles, United States
Itzhak Fried: ORCiD; Department of Neurosurgery, University of California, Los Angeles, United States; Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, United States

DOI: https://doi.org/10.7554/eLife.29515
Journal volume & issue: Vol. 6

Abstract

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The hippocampus is critical for episodic memory, and synaptic changes induced by long-term potentiation (LTP) are thought to underlie memory formation. In rodents, hippocampal LTP may be induced through electrical stimulation of the perforant path. To test whether similar techniques could improve episodic memory in humans, we implemented a microstimulation technique that allowed delivery of low-current electrical stimulation via 100 μm-diameter microelectrodes. As thirteen neurosurgical patients performed a person recognition task, microstimulation was applied in a theta-burst pattern, shown to optimally induce LTP. Microstimulation in the right entorhinal area during learning significantly improved subsequent memory specificity for novel portraits; participants were able both to recognize previously-viewed photos and reject similar lures. These results suggest that microstimulation with physiologic level currents—a radical departure from commonly used deep brain stimulation protocols—is sufficient to modulate human behavior and provides an avenue for refined interrogation of the circuits involved in human memory.

Published in eLife

ISSN: 2050-084X (Online)
Publisher: eLife Sciences Publications Ltd
Country of publisher: United Kingdom
LCC subjects: Medicine; Science: Biology (General)
Website: https://elifesciences.org

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