TY - JOUR
T1 - Memory signals from the thalamus
T2 - early thalamocortical phase synchronization entrains gamma oscillations during long-term memory retrieval
AU - Staudigl, Tobias
AU - Zaehle, Tino
AU - Voges, Jürgen
AU - Hanslmayr, Simon
AU - Esslinger, Christine
AU - Hinrichs, Hermann
AU - Schmitt, Friedhelm C
AU - Heinze, Hans-Jochen
AU - Richardson-Klavehn, Alan
N1 - Copyright © 2012 Elsevier Ltd. All rights reserved.
PY - 2012/12
Y1 - 2012/12
N2 - 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.
AB - 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.
KW - Adult
KW - Brain Mapping
KW - Cortical Synchronization
KW - Electroencephalography
KW - Female
KW - Humans
KW - Male
KW - Memory, Long-Term
KW - Recognition (Psychology)
KW - Thalamus
KW - Time Factors
KW - Young Adult
U2 - 10.1016/j.neuropsychologia.2012.08.023
DO - 10.1016/j.neuropsychologia.2012.08.023
M3 - Article
C2 - 22975190
SN - 0028-3932
VL - 50
SP - 3519
EP - 3527
JO - Neuropsychologia
JF - Neuropsychologia
IS - 14
ER -