Biology subjects

Drongelen, W. v.

Publications and source records attributed to Drongelen, W. v..

3 recordsLinked to original sources

bioRxiv2026

Thalamic Nuclei Differentially Coordinate Propagation of Cortical Slow Oscillations

Sleep slow oscillations (SOs) vary in the spatial extent of their cortical propagation, ranging from widespread Global events to spatially restricted Frontal events. These distinctions could have functional consequences for memory consolidation. It remains unknown whether individual thalamic nuclei are differentially engaged across SO propagation types, and whether thalamic activity before SO onset predicts subsequent propagation. We analyzed simultaneous scalp EEG and thalamic stereo-EEG from 24 full-night recordings in 6 epilepsy patients, sampling 11 thalamic nuclei and enabling direct characterization of nucleus-specific thalamocortical interactions during naturally occurring sleep slow oscillations. Cortical SOs were classified by propagation type and thalamocortical coupling was characterized via peri-event histograms, phase-locking analysis, waveform morphology comparisons, and pre-onset spectral and cross-frequency coupling features. All well-sampled thalamic nuclei showed broad temporal co-occurrence with prefrontal SOs, yet occupied distinct phase positions within the cortical SO cycle. Medial pulvinar (PuM) showed the strongest phase locking across subjects, with significant preference for the ascending post-trough phase. Among the examined nuclei, Frontal SOs were associated with significant phase locking in PuM, whereas Global SOs preferentially synchronized the centromedian nucleus near the cortical down-state trough. Thalamic waveform morphology differed systematically with propagation extent, with opposing effects between pulvinar and intralaminar nuclei. Pre-onset PuM activity showed suppressed alpha, sigma, and beta power and delta-phase cross-frequency coupling before Global SOs (all p < 0.05). The human thalamus engages NREM sleep SOs through nucleus-specific, propagation-sensitive dynamics rather than as a functionally uniform structure. Pre-onset PuM activity contains predictive signatures of cortical SO propagation extent. This finding has implications for closed-loop neuromodulation targeting specific SO states, although replication in larger cohorts is needed.

neuroscience↗

bioRxiv2026

Slow Oscillations Gate Interictal Spikes Across the Human Thalamocortical-Epileptogenic Network

BackgroundSlow oscillations (SOs; 0.5-1.5 Hz), a hallmark of non-rapid eye movement (NREM) sleep, are associated with a marked amplification of interictal epileptiform spike (IIS) activity in focal epilepsy. However, the network-level organization of this effect across the thalamocortical-epileptogenic system, and whether IIS-permissive SOs can be predicted from pre-onset brain states, remain unclear. MethodsWe analyzed simultaneous scalp EEG and stereo-EEG (SEEG) recordings from 6 patients with drug-resistant focal epilepsy across 24 full-day recording days, sampling prefrontal cortex (PFC), thalamus, and seizure onset zone (SOZ). SO-IIS coupling was characterized across vigilance states using peri-event and phase-based analyses, with a gamma-based validation step to reduce contamination by IIS-related slow potentials. Pre-onset phase-amplitude coupling (PAC) was compared between IIS-permissive and non-permissive SOs. ResultsSO-IIS coupling was observed across all regions, with the strongest and most temporally precise pre-trough IIS clustering in the SOZ (peak 4.4% in NREM), exceeding PFC (1.7%) and thalamic coupling. Thalamic coupling was preserved across wakefulness and NREM and was significant in 7/11 nuclei, with nucleus-specific phase preferences. SO morphological features, particularly up-slope and peak-to-peak amplitude at PFC contacts, predicted IIS occurrence in the SOZ. Pre-onset PAC differed significantly between permissive and non-permissive SOs across regions. ConclusionsSO-IIS coupling is a distributed, network-level phenomenon with region- and state-specific characteristics, and pre-onset PAC provides a predictive signature of IIS-permissive brain states. These findings support the feasibility of developing personalized, closed-loop neuromodulatory strategies targeting SO-gated IIS suppression in focal epilepsy.

neuroscience↗

bioRxiv2026

Predictability of Sleep Slow Oscillation Emergence and Spatial Extent from Pre-Onset Neural Dynamics

Slow oscillations (SOs; [~]0.5-1.5 Hz) are a hallmark of non-rapid eye movement (NREM) sleep and are known to support memory consolidation and large-scale cortical communication. Although their instantaneous dynamics are well characterized, the neural processes that precede SO initiation--and whether they predict the spatial extent of the upcoming event--remain largely unknown, despite their potential utility for anticipatory closed-loop intervention. Using high-density EEG from 29 healthy adults, we examined neural activity in the 2-s interval preceding the SO trough. Analyses focused on distinct SO subtypes defined by their spatiotemporal properties: Global, Frontal, and Local. We specifically focused on Global and Frontal events, both of which originate frontally but differ in their propagation. We quantified instantaneous spectral power, time-frequency dynamics, phase-amplitude coupling (PAC), and amplitude-amplitude coupling. Across all analyses, theta-band power (4-8 Hz) emerged as the earliest and most robust predictor of SO initiation, remaining informative after restricting analyses to temporally isolated SOs to reduce potential residual-aftereffect confounds from preceding SOs. Theta power exhibited a sustained rise beginning nearly two seconds before the SO trough ([~]1.6 s before onset). Theta power increases were absent in surrogate epochs and reliably differentiated Global from Frontal SOs with moderate-to-strong effect sizes (Cohens d = 0.45-0.77), demonstrating the robustness of theta power as a physiological signature. Mechanistically, Global SOs were preceded by enhanced delta-theta PAC and broad low-frequency synchronization, whereas Frontal SOs were preceded by elevated theta/alpha-to-beta/low-gamma coupling, reflecting a state of locally enhanced coupling at frequencies higher than the SO range, which appears to restrict propagation. A simple logistic regression classifier using only pre-onset theta power achieved >95% accuracy in distinguishing SOs from surrogate events and differentiated Global from Frontal SOs with [~]83% multiclass accuracy, showing further sensitivity improvements when delta power was included. These findings demonstrate that isolated SOs are preceded by structured network dynamics that are tied to their spatial extent. Thus, theta activity can be used to predict SO occurrence and might be leveraged in closed-loop neuromodulation.

neuroscience↗