Epilepsy, cognition, and neuropsychiatry (Epilepsy, Brain, and Mind, part 2)

Korczyn, Amos D.; Schachter, Steven C.; Brodie, Martin J.; Dalal, Sarang S.; Engel, Jerome; Guekht, Alla; Hečimović, Hrvoje; Jerbi, Karim; Kanner, Andrés M.; Landmark, Cecilie Johannessen; Mareš, Pavel; Marusič, Petr; Meletti, Stefano; Mula, Marco; Patsalos, Philip N.; Reuber, Markus; Ryvlin, Philippe; Štillová, Klára; Tuchman, Roberto; Rektor, Ivan

doi:10.1016/j.yebeh.2013.03.012

Cited by 47 publications

(37 citation statements)

References 184 publications

(210 reference statements)

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“…Considering these constraints, our EEG localization and fMRI results still exhibited a relatively good fit despite the low spatial resolution of EEG (Fuchs et al, 2002) and the low temporal resolution of fMRI. The widespread topography of scalp-recorded EEG theta effects with temporal and frontal peaks is similar to topographies in prior studies reporting MTL sources of theta power effects (Staudigl and Hanslmayr, 2013; Backus et al, 2016) and also fits with the assumption that deep sources are reflected in more widespread sensor-level effects (Dalal et al, 2013). Our source localization results are also corroborated by studies showing MTL theta effects similarly in sensor-level source reconstructions and intracranial recordings directly in the MTL (Dalal et al, 2013; Crespo-García et al, 2016).…”

Section: Discussionsupporting

confidence: 82%

Spatial Mnemonic Encoding: Theta Power Decreases and Medial Temporal Lobe BOLD Increases Co-Occur during the Usage of the Method of Loci

Fellner

Volberg

Wimber

et al. 2016

eNeuro

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The method of loci is one, if not the most, efficient mnemonic encoding strategy. This spatial mnemonic combines the core cognitive processes commonly linked to medial temporal lobe (MTL) activity: spatial and associative memory processes. During such processes, fMRI studies consistently demonstrate MTL activity, while electrophysiological studies have emphasized the important role of theta oscillations (3–8 Hz) in the MTL. However, it is still unknown whether increases or decreases in theta power co-occur with increased BOLD signal in the MTL during memory encoding. To investigate this question, we recorded EEG and fMRI separately, while human participants used the spatial method of loci or the pegword method, a similarly associative but nonspatial mnemonic. The more effective spatial mnemonic induced a pronounced theta power decrease source localized to the left MTL compared with the nonspatial associative mnemonic strategy. This effect was mirrored by BOLD signal increases in the MTL. Successful encoding, irrespective of the strategy used, elicited decreases in left temporal theta power and increases in MTL BOLD activity. This pattern of results suggests a negative relationship between theta power and BOLD signal changes in the MTL during memory encoding and spatial processing. The findings extend the well known negative relation of alpha/beta oscillations and BOLD signals in the cortex to theta oscillations in the MTL.

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Section: Discussionsupporting

confidence: 82%

Spatial Mnemonic Encoding: Theta Power Decreases and Medial Temporal Lobe BOLD Increases Co-Occur during the Usage of the Method of Loci

Fellner

Volberg

Wimber

et al. 2016

eNeuro

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“…Indeed, simultaneous MEG and intracranial data from drug resistant epileptic patients strong ly suggest that MEG can detect hippocampal theta activity. With such recordings, it has been observed that surface magnetic activity and hip pocampal theta recorded with depth electrodes were practically over lapped, without phase delay (Dalal et al, 2013). Another simultaneous MEG iEEG study demonstrated that epileptic spikes generated in the hippocampus are sometimes observable with MEG (Santiuste et al, 2008).…”

Section: Successful Reconstruction Of Slow Theta Sources In the Hippomentioning

confidence: 99%

Slow-theta power decreases during item-place encoding predict spatial accuracy of subsequent context recall

et al. 2016

Self Cite

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a b s t r a c tHuman hippocampal theta oscillations play a key role in accurate spatial coding. Associative encoding involves similar hippocampal networks but, paradoxically, is also characterized by theta power decreases. Here, we inves tigated how theta activity relates to associative encoding of place contexts resulting in accurate navigation. Using MEG, we found that slow theta (2 5 Hz) power negatively correlated with subsequent spatial accuracy for vir tual contextual locations in posterior hippocampus and other cortical structures involved in spatial cognition. A rare opportunity to simultaneously record MEG and intracranial EEG in an epilepsy patient provided crucial in sights: during power decreases, slow theta in right anterior hippocampus and left inferior frontal gyrus phase led the left temporal cortex and predicted spatial accuracy. Our findings indicate that decreased slow theta activ ity reflects local and long range neural mechanisms that encode accurate spatial contexts, and strengthens the view that local suppression of low frequency activity is essential for more efficient processing of detailed information.

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“…Much research has since been devoted to demonstrating this association in different populations. The notion of psychiatric and behavioral disorders as part of the spectrum of the expression of epilepsy has become generally accepted …”

Section: The Bidirectional Hypothesismentioning

confidence: 99%

Psychiatric and behavioral comorbidities in epilepsy: A critical reappraisal

2017

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Psychiatric and behavioral disorders are important aspects of epilepsy and have received increasing attention in the last several years. The literature upon which most of the field relies contains some biases that must be carefully examined and resolved in future studies: (1) In the pediatric epilepsy literature, many reports find children with epilepsy have high levels of behavioral and psychiatric disorders when compared to appropriate controls. Most of these studies rely on parent-proxy completed instruments to assess these behavioral endpoints. Parents’ reports are not objective but reflect parents’ reactions and emotions. Increasing evidence suggests inherent biases in proxy reports and highlights the need to assess children directly. (2) Peri-ictal phenomena may be mischaracterized as underlying mood disorders. (3) Many studies report elevated levels of psychiatric morbidity before and after the diagnosis of epilepsy suggesting an inherent relation between the two types of disorders. Psychogenic nonepileptic seizures, while widely recognized as posing a diagnostic dilemma in the clinic, may account for some of these research findings. Diagnostic errors between epilepsy and PNES need careful consideration when evaluating studies demonstrating associations between psychiatric disorders and epilepsy or poorer seizure control in association with psychiatric disorders in people who have epilepsy. Mental health concerns are important for everyone. An accurate, undistorted understanding of the relation between mental health disorders and epilepsy is essential to insure appropriate therapy and avoid unnecessary and potentially harmful treatments and avoid common misconceptions.

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Epilepsy, cognition, and neuropsychiatry (Epilepsy, Brain, and Mind, part 2)

Cited by 47 publications

References 184 publications

Spatial Mnemonic Encoding: Theta Power Decreases and Medial Temporal Lobe BOLD Increases Co-Occur during the Usage of the Method of Loci

Spatial Mnemonic Encoding: Theta Power Decreases and Medial Temporal Lobe BOLD Increases Co-Occur during the Usage of the Method of Loci

Slow-theta power decreases during item-place encoding predict spatial accuracy of subsequent context recall

Psychiatric and behavioral comorbidities in epilepsy: A critical reappraisal

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