Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2007 Nov;130(Pt 11):2868-78.
doi: 10.1093/brain/awm146. Epub 2007 Jul 5.

Temporal coupling of parahippocampal ripples, sleep spindles and slow oscillations in humans

Zsófia Clemens  1 , Matthias Mölle, Lóránd Eross, Péter Barsi, Péter Halász, Jan Born
Affiliations
Comparative Study

Temporal coupling of parahippocampal ripples, sleep spindles and slow oscillations in humans

Zsófia Clemens et al. Brain. 2007 Nov.

Abstract

Ripples are high-frequency oscillation bursts in the mammalian hippocampus mainly present during Non-REM sleep. In rodents they occur in association with sharp waves and are grouped by the cortical slow oscillation such that, in parallel with sleep spindles, ripple activity is suppressed during the hyperpolarized down-state and enhanced during the depolarized up-state. The temporal coupling between slow oscillations, spindles and ripples has been suggested to serve a hippocampo-neocortical dialogue underlying memory consolidation during sleep. Here, we examined whether a similar coupling exists between these oscillatory phenomena in humans. In sleep recordings from seven epileptic patients, scalp-recorded slow oscillations and spindles as well as parahippocampal ripples recorded from foramen ovale electrodes were identified by automatic algorithms. Additionally, ripple and spindle root mean square activity was determined for relevant frequency bands. Ripple density was higher during Non-REM than REM sleep (P < 0.001). Ripple activity distinctly decreased time-locked to slow oscillation negative half-waves in the three patients without temporal structural alterations (P < 0.001), whereas in the four patients with severe mesiotemporal structural alterations this coupling was obscure. Generally, in the patients ripple activity was increased before spindle peaks and distinctly decreased after the peak (P < 0.001). Ripples were consistently associated with interictal spikes suggesting that spike-ripple complexes represent an epileptic transformation of sharp wave-ripple complexes in the epileptic hippocampus. Our findings are consistent with the notion of a hippocampo-to-neocortical information transfer during sleep that is linked to coordinate ripple and spindle activity, and that in the intact temporal lobe is synchronized to cortical slow oscillations.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

Publication types

LinkOut - more resources