Slow spindles are associated with cortical high frequency activity

Hashemi, Nasrin; Dehnavi, Fereshteh; Moghimi, Sahar; Ghorbani, Maryam

doi:10.1016/j.neuroimage.2019.01.012

Cited by 23 publications

(34 citation statements)

References 33 publications

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“…It would be too speculative to make any assumption on specific neocortical and/or neocortical-subcortical network interactions. Moreover, activity of the up-to-down and down-to-up states are not independent, resulting from local activity and long-range neuronal connections as well as from nonneuronal responses [ 35 , 90–94 ]. We suggest that future studies investigate whether information on the interplay of sequential neural circuitry during the falling and rising phase of the SO can be related to so-tDCs efficacy, and that studies confirm ties between baseline sleep and task-dependent so-tDCS efficacy.…”

Section: Discussionmentioning

confidence: 99%

Spontaneous slow oscillation—slow spindle features predict induced overnight memory retention

Dehnavi

Koo‐Poeggel

Ghorbani

et al. 2021

Sleep

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Study Objectives Synchronization of neural activity within local networks and between brain regions is a major contributor to rhythmic field potentials such as the EEG. On the other hand, dynamic changes in microstructure and activity are reflected in the EEG, for instance slow oscillation (SO) slope can reflect synaptic strength. SO-spindle coupling is a measure for neural communication. It was previously associated with memory consolidation, but also shown to reveal strong inter-individual differences. In studies, weak electric current stimulation has modulated brain rhythms and memory retention. Here we investigate whether SO-spindle coupling and SO slope during baseline sleep are associated with (predictive of) stimulation efficacy on retention performance. Methods Twenty-five healthy subjects participated in three experimental sessions. Sleep-associated memory consolidation was measured in two sessions, in one anodal transcranial direct current stimulation oscillating at subjects individual SO frequency (so-tDCS) was applied during nocturnal sleep. The third session was without a learning task (baseline sleep). The dependence on SO-spindle coupling and SO-slope during baseline sleep of so-tDCS efficacy on retention performance were investigated. Results Stimulation efficacy on overnight retention of declarative memories was associated with nesting of slow spindles to SO trough in deep non-rapid eye movement baseline sleep. Steepness and direction of SO slope in baseline sleep were features indicative for stimulation efficacy. Conclusions Findings underscore a functional relevance of activity during the SO up-to-down state transition for memory consolidation and provide support for distinct consolidation mechanisms for types of declarative memories.

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Section: Discussionmentioning

confidence: 99%

Spontaneous slow oscillation—slow spindle features predict induced overnight memory retention

Dehnavi

Koo‐Poeggel

Ghorbani

et al. 2021

Sleep

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“…Hashemi et al (2019) recently examined the interrelationship between sleep-spindles activity and higher frequencies (∼25.0 Hz). In their model, the cortical high frequency activity and its interaction with thalamic oscillation at fast spindle are proposed as key mechanism for the generation of slow spindles.…”

Section: Discussionmentioning

confidence: 99%

“…However, an exhaustive description of spindles local features is not possible with LORETA algorithm, due to its limited potential for the identification and localization of multiple and concomitant cortical sources (Nir et al, 2011; Piantoni et al, 2017; Hagler et al, 2018). Moreover, LORETA does not take into account co-localized sources, possibly explaining the key role of modulation of cortical spontaneous activity in the genesis of spindle (Hashemi et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

Spatiotemporal Dynamics of Sleep Spindle Sources Across NREM Sleep Cycles

et al. 2019

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The existence of two different types of sleep spindles (slow and fast) is well-established, according to their topographical distribution at scalp- and cortical-level. Our aim was to provide a systematic investigation focused on the temporal evolution of sleep spindle sources during non-rapid eye movement (NREM) sleep. Spindle activity was recorded and automatically detected in 20 healthy subjects. Low resolution brain electromagnetic tomography (LORETA) was applied for the EEG source localization. Aiming to evaluate the time course of the detected slow and fast spindle sources, we considered the first four NREM sleep cycles and divided each cycle into five intervals of equal duration. We confirmed the preferential localization in the frontal (Brodmann area 10) and parietal (Brodmann area 7) cortical regions, respectively for slow (11.0–12.5) and fast (13.0–14.5) spindles. Across subsequent NREM sleep episodes, the maximal source activation remained systematically located in Brodmann area 10 and Brodmann area 7, showing the topographical stability of the detected generators. However, a different time course was observed as a function of the type of spindles: a linear decrease across subsequent cycles was found for slow spindle but not for fast spindle source. The intra-cycle variations followed a “U” shaped curve for both spindle source, with a trough around third and fourth interval (middle part) and the highest values at the beginning and the end of the considered temporal window. We confirmed the involvement of the frontal and parietal brain regions in spindle generation, showing for the first time their changes within and between consecutive NREM sleep episodes. Our results point to a correspondence between the scalp-recorded electrical activity and the underlying source topography, supporting the notion that spindles are not uniform phenomena: complex region- and time-specific patterns are involved in their generation and manifestation.

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Section: Discussionmentioning

confidence: 99%

“…It has been hypothesized that the phase of the slower oscillation generally reflects greater excitability among postsynaptic neurons, which in turn synchronizes the synaptic input (as reflected by an increase in the amplitude of the faster oscillation) (Bergmann & Born, 2018). In adults, the mechanisms underlying PAC lead to specific temporal patterns of coupling across multiple frequencies at both local and distal sites (Bergmann & Born, 2018; Engel et al, 2013; Hashemi, Dehnavi, Moghimi, & Ghorbani, 2019; Hyafil et al, 2015). This coupling can be modulated by structural changes (Helfrich et al, 2018; Salimpour & Anderson, 2019), and task‐related network dynamics (suggesting a functional role for the CFC) (Canolty & Knight, 2010; Combrisson et al, 2017; Engel et al, 2013; Haegens, Nácher, Luna, Romo, & Jensen, 2011; Tort, Komorowski, Manns, Kopell, & Eichenbaum, 2009).…”

Section: Discussionmentioning

confidence: 99%

The intimate relationship between coalescent generators in very premature human newborn brains: Quantifying the coupling of nested endogenous oscillations

Moghimi

Shadkam

Mahmoudzadeh

et al. 2020

Human Brain Mapping

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Temporal theta slow-wave activity (TTA-SW) in premature infants is a specific neurobiomarker of the early neurodevelopment of perisylvian networks observed as early as 24 weeks of gestational age (wGA). It is present at the turning point between non-sensory driven spontaneous networks and cortical network functioning. Despite its clinical importance, the underlying mechanisms responsible for this spontaneous nested activity and its functional role have not yet been determined. The coupling between neural oscillations at different timescales is a key feature of ongoing neural activity, the characteristics of which are determined by the network structure and dynamics. The underlying mechanisms of cross-frequency coupling (CFC) are associated with several putative functions in adults. In order to show that this generic mechanism is already in place early in the course of development, we analyzed electroencephalography recordings from sleeping preterm newborns (24-27 wGA). Employing cross-frequency phase-amplitude coupling analyses, we found that TTAs were orchestrated by the SWs defined by a precise temporal relationship. Notably, TTAs were synchronized to the SW trough, and were suppressed during the SW peak. Spontaneous endogenous TTA-SWs constitute one of the very early signatures of the developing temporal neural networks with key functions, such as language and communication. The presence of a fine-tuned relationship between the slow activity and the TTA in premature neonates emphasizes the complexity and relative maturity of the intimate mechanisms that shape the CFC, the disruption of which can have severe neurodevelopmental consequences.

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Slow spindles are associated with cortical high frequency activity

Cited by 23 publications

References 33 publications

Spontaneous slow oscillation—slow spindle features predict induced overnight memory retention

Spontaneous slow oscillation—slow spindle features predict induced overnight memory retention

Spatiotemporal Dynamics of Sleep Spindle Sources Across NREM Sleep Cycles

The intimate relationship between coalescent generators in very premature human newborn brains: Quantifying the coupling of nested endogenous oscillations

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