Theta synchronization in the human EEG and episodic retrieval

  title={Theta synchronization in the human EEG and episodic retrieval},
  author={Michael Doppelmayr and Wolfgang Klimesch and J Schwaiger and P Auinger and T. Winkler},
  journal={Neuroscience Letters},
Event-related desynchronization (ERD) and synchronization (ERS) was measured during episodic retrieval in a specially designed recognition task which forces subjects to avoid semantic search strategies. ERD represents the percentage of a decrease, ERS an increase in band power. The results show that only the theta band differentiates between good and bad episodic memory performers and that good performance is related to a large degree of theta synchronization. The delta and alpha bands did not… 
Sensitivity of human EEG alpha band desynchronization to different working memory components and increasing levels of memory load
A linearly increasing desynchronization in the upper alpha band with ascending cognitive load is found, and evidence of the involvement of distinguishable cognitive components in the memory tasks is found.
Theta and High-Frequency Activity Mark Spontaneous Recall of Episodic Memories
It is found that retrieval evolved in three electrophysiological stages composed of: (1) early theta oscillations in the right temporal cortex, (2) increased HFA in the left hemisphere including the medial temporal lobe, left inferior frontal gyrus, as well as the ventrolateralporal cortex, and (3) motor/language activation during vocalization of the retrieved item.
Intelligence related differences in EEG-bandpower
A significant interaction of task difficulty and IQ group in the upper alpha band is found, indicating both, a weaker activation for the high IQ group during the easy tasks, and a significant increase from easy to difficult tasks for IQ+ only.
Affective picture processing: event-related synchronization within individually defined human theta band is modulated by valence dimension.
The findings document that valence discrimination is associated with the early (200-500 ms poststimulus) time-locked synchronized theta activity as well as hemispheric asymmetries in anterior-posterior direction.
Event-Related Synchronization and Desynchronization During Affective Processing: Emergence of Valence-Related Time-Dependent Hemispheric Asymmetries in Theta and Upper Alpha Band
The obtained findings indicate that differences induced by pictures varying in emotional valence are associated mainly with increased theta and alpha-3 synchronization activity and anterior hemispheric asymmetries.
Event-Related Desynchronization of Frontal-Midline Theta Rhythm during Preconscious Auditory Oddball Processing
The frontal-mid-line theta rhythm (Fm theta) generation mechanism employing event-related desynchronization/synchronization (ERD/ERS) analysis in relation to task-irrelevant external stimuli was explored.
Neural Dynamics Associated with Semantic and Episodic Memory for Faces: Evidence from Multiple Frequency Bands
Investigation of neuroelectric dynamics during the creation and the retrieval of episodic memories for famous and nonfamous faces provides new insights into the complex interaction between semantic and episodic memory for faces and the neural dynamics associated with mnemonic processes.
Theta oscillations in top-down control of episodic memory retrieval
The final copy of this thesis has been examined by the signatories, and we find that both the content and the form meet acceptable presentation standards of scholarly work in the above-mentioned
Time-dependent cortical asymmetries induced by emotional arousal: EEG analysis of event-related synchronization and desynchronization in individually defined frequency bands.
The hemispheric asymmetries revealed point to recruitment of not only posterior regions of the right hemisphere (theta and alpha-1 bands), but also of anterior areas of the left hemisphere ( theta andalpha-3 bands) in affect analysis beyond valence dimension.
Functional role of gamma and theta oscillations in episodic memory
It is proposed here that gamma and theta oscillations allow for the transient interaction between cortical structures and the hippocampus for the encoding and retrieval of episodic memories as described by the hippocampal memory indexing theory.


Brain oscillations and human memory: EEG correlates in the upper alpha and theta band
The results show that the upper alpha band is most sensitive to the encoding and processing of semantic information, and it is only the upperalpha band that distinguishes between good and bad semantic memory performers and that shows significant correlations with semantic memory performance during that time period, semantic processing actually takes place.
Episodic and semantic memory: an analysis in the EEG theta and alpha band.
This study examines the hypothesis that in contrast to semantic memory processes that are assumed to be reflected primarily within the alpha band, episodic memory processes are related to activity within the theta band and shows that semanticMemory processes are indeed primarily reflected in the upper alpha band whereas episodicmemory processes are reflected inTheta band.
Short duration synchronization of human theta rhythm during recognition memory
There are short duration changes in the human theta rhythm associated with recognition memory and this increase was more than twice as great for repeated words as for new ones.
Event-related desynchronization (ERD) and the Dm effect: does alpha desynchronization during encoding predict later recall performance?
The results show that for good performers, the extent of ERD in the lower alpha band during the semantic encoding for words is significantly larger for remembered as compared to not remembered words, whereas for bad performers the ERE in the upper alpha band is significantly more pronounced.
Memory processes, brain oscillations and EEG synchronization.
  • W. Klimesch
  • Psychology, Medicine
    International journal of psychophysiology : official journal of the International Organization of Psychophysiology
  • 1996
Results in memory research from divergent disciplines such as cognitive psychology, neuroanatomy, and neurophysiology are integrated to support the hypothesis that short-term (episodic) memory demands lead to a synchronization (increase in band power) in the theta band, whereas long- term (semantic) memory processes are reflected by oscillations in a posterior-thalamic system.
Event-related cortical desynchronization detected by power measurements of scalp EEG.
Changes in the background EEG activity occurring at the same time as visual and auditory evoked potentials, as well as during the interstimulus interval in a CNV paradigm were analysed in human
PET studies of encoding and retrieval: The HERA model
We review positron emission tomography (PET) studies whose results converge on the hemispheric encoding/retrieval asymmetry (HERA) model of the involvement of prefrontal cortical regions in the
Individual differences in brain dynamics: important implications for the calculation of event-related band power
This new method to adjust the frequency bands to the individual alpha frequency (IAF) for each subject and to determine the bandwidth for the alpha and theta bands as a percentage of IAF is proposed.
Hemispheric encoding/retrieval asymmetry in episodic memory: positron emission tomography findings.
A hemispheric encoding/retrieval asymmetry model of prefrontal involvement in encoding and retrieval of episodic memory is proposed, which suggests that left and right prefrontal lobes are part of an extensive neuronal network that subserves episodic remembering, but the two prefrontal hemispheres play different roles.
Neuroanatomical correlates of retrieval in episodic memory: auditory sentence recognition.
The prevalence of sulcal blood-flow changes may reflect extensive cortical gyrification; it may also indicate that memory-related processes rely on the densely packed neuropil of sulCal regions.