Memory signals from the thalamus: early thalamocortical phase synchronization entrains gamma oscillations during long-term memory retrieval

Research output: Contribution to journalArticlepeer-review

Authors

  • Tobias Staudigl
  • Tino Zaehle
  • Jürgen Voges
  • Christine Esslinger
  • Hermann Hinrichs
  • Friedhelm C Schmitt
  • Hans-Jochen Heinze
  • Alan Richardson-Klavehn

Colleges, School and Institutes

Abstract

The thalamus is believed to be a key node in human memory networks, however, very little is known about its real-time functional role. Here we examined the dynamics of thalamocortical communication during long-term episodic memory retrieval in two experiments. In experiment 1, intrathalamic and surface EEG was recorded in an epileptic patient implanted with depth electrodes for brain stimulation therapy. In a recognition memory test, early (300-500 ms) stimulus-linked oscillatory synchrony between mediodorsal thalamic and frontal surface electrodes at beta frequency (20 Hz) was enhanced for correctly remembered old compared to correctly rejected new items. Directionality measures (Granger causality) indicated that the thalamus was the sender, and the neocortex the receiver, of this beta signal, which also modulated the power of neocortical gamma (55-80 Hz) oscillations (cross-frequency coupling). Experiment 2 validated the cross-frequency coupling effects in a healthy participant sample. Confirming the findings from experiment 1, significantly increased cross-frequency coupling was found over frontal scalp electrodes during successful recognition. Extending anatomical knowledge on thalamic connectivity with frontal neocortex, these results suggest that the thalamus sends an early memory signal to frontal regions, triggering further memory search processes.

Bibliographic note

Copyright © 2012 Elsevier Ltd. All rights reserved.

Details

Original languageEnglish
Pages (from-to)3519-27
Number of pages9
JournalNeuropsychologia
Volume50
Issue number14
Publication statusPublished - Dec 2012

Keywords

  • Adult, Brain Mapping, Cortical Synchronization, Electroencephalography, Female, Humans, Male, Memory, Long-Term, Recognition (Psychology), Thalamus, Time Factors, Young Adult

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