Author: Oliva A1, Fernández-Ruiz A2, Fermino de Oliveira E3, Buzsáki G4
Affiliation: <sup>1</sup>New York University Neuroscience Institute, New York, NY 10016, USA; Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.
<sup>2</sup>New York University Neuroscience Institute, New York, NY 10016, USA.
<sup>3</sup>New York University Neuroscience Institute, New York, NY 10016, USA; Center for Mathematics, Computing and Cognition, Universidade Federal do ABC, São Bernardo do Campo, São Paulo, Brazil.
<sup>4</sup>New York University Neuroscience Institute, New York, NY 10016, USA; Center for Neural Science, New York University, New York, NY 10016, USA. Electronic address: gyorgy.buzsaki@nyumc.org.
Conference/Journal: Cell Rep.
Date published: 2018 Nov 13
Other:
Volume ID: 25 , Issue ID: 7 , Pages: 1693-1700 , Special Notes: doi: 10.1016/j.celrep.2018.10.066. , Word Count: 166
Hippocampal sharp-wave ripples (SPW-Rs) support consolidation of recently acquired episodic memories and planning future actions by generating ordered neuronal sequences of previous or future experiences. SPW-Rs are characterized by several spectral components: a slow (5-15 Hz) sharp-wave, a high-frequency "ripple" oscillation (150-200 Hz), and a slow "gamma" oscillation (20-40 Hz). Using laminar hippocampal recordings and optogenetic manipulations, we dissected the origin of these spectral components. We show that increased power in the 20-40 Hz band does not reflect an entrainment of CA1 and CA3 neurons at gamma frequency but the power envelope of overlapping ripples. Spike-local field potential coupling between unit firing in CA1 and CA3 regions during SPW-Rs is lowest in the gamma band. Longer SPW-Rs are preceded by increased firing in the entorhinal cortex. Thus, fusion of SPW-Rs leads to lengthening of their duration associated with increased power in the slow gamma band without the presence of true oscillation.
KEYWORDS: entorhinal cortex; gamma; hippocampus; memory consolidation; optogenetics; oscillations; sharp-wave ripples
PMID: 30428340 DOI: 10.1016/j.celrep.2018.10.066