Biology subjects

Fattinger, S.

Publications and source records attributed to Fattinger, S..

4 recordsLinked to original sources

bioRxiv2025

The Infraslow Fluctuation of Sigma Power During Sleep in Young Individuals with Schizophrenia

A reduction in sleep spindles, a major electrophysiological characteristic of Non-Rapid Eye Movement sleep, has been suggested as a potential biomarker of schizophrenia. While research has primarily focused on the spindle quantity, recent studies have begun to explore their temporal dynamics throughout the night. In healthy individuals, sleep spindles fluctuate on an infraslow [~]50-second timescale, alternating between phases of high and low spindle activity. This fluctuation is referred to as the infraslow fluctuation of sigma power (ISFS), which is modulated by noradrenergic activity from the locus coeruleus and linked to the organization of arousal and memory reactivation processes during sleep. Given the known deficit in sleep spindles, dysregulation of noradrenergic activity, and impairments in sleep maintenance and memory in schizophrenia, this study investigates the ISFS in sleep electroencephalography data from individuals with either Childhood-Onset Schizophrenia (COS; N = 17) or Early-Onset Schizophrenia (EOS; N = 11), aged 9 to 21 years, alongside age- and sex-matched healthy controls (N = 56). The presence and strength of the ISFS were reduced in both COS and EOS groups compared to controls, particularly in central-parietal electrodes. No significant differences in these features of the ISFS were found between the two clinical groups, despite group differences in sleep spindle density and clinical characteristics. These findings suggest that the ISFS is observable but reduced in young patients with schizophrenia and support the notion that the timing of sleep spindles may inform pathomechanistic models of the disorder, as well as future diagnostic approaches and interventions.

neuroscience↗

bioRxiv2025

Local modulation of sleep slow waves depends on timing between auditory stimuli

Conflicting evidence exists regarding the role of the targeted slow-wave phase in determining the direction and spatial specificity of slow-wave activity (SWA) modulation via phase-targeted auditory stimulation (PTAS) during sleep. To reconcile these discrepancies, we re-analyzed high-density electroencephalography (hd-EEG) data from previous studies, focusing on SWA responses to auditory stimuli presented with varying inter-stimulus intervals (ISIs). Our analysis reveals that ISI is a primary determinant of PTAS-induced SWA modulation, exceeding the influence of targeted phase alone. Specifically, auditory stimulation with longer ISIs evoked a global increase in SWA, consistent with a stereotypical auditory-evoked K-complex (KC), independent of targeted phase. Conversely, longer stimulus trains with rapid successive stimulus presentation resulted in spatially localized, phase-dependent SWA modulation, with up-PTAS enhancing and down-PTAS reducing SWA locally around the targeted area. This distinction resolves inconsistencies in prior PTAS studies by demonstrating that phase alone in insufficient in predicting slow-wave responses. Rather, it was the ISI which determined whether PTAS resulted in a global, KC-mediated response or a local, phase-specific modulation of SWA. Consequently, our findings refine the mechanistic understanding of PTAS, suggesting that ISI regulates the engagement of distinct neural circuits and thereby potentially enables the targeted manipulation of specific slow-wave subtypes and their associated functions.

neuroscience↗

bioRxiv2024

Longer Interstimulus Intervals Enhance Efficacy of Automated Phase-Targeted Auditory Stimulation on Procedural Memory Consolidation

Up-phase-targeted auditory stimulation (up-PTAS) during slow-wave sleep has become a valuable tool for modulating slow oscillations and slow-oscillation-spindle-coupling in favor of overnight memory retention. Developing effective, automated protocols for translation into more naturalistic or clinical settings is an ongoing challenge, especially given that current PTAS protocols and their behavioral effects vary greatly between different studies. Here, we assessed the electrophysiological and behavioral effects of systematically varying interstimulus intervals (ISIs) in automated up-PTAS in the home setting, using a mobile PTAS device and app-based behavioral tasks. Building on studies suggesting a non-linear relationship between stimulus number and PTAS effects, we show that applying fewer stimuli with longer ISIs enhanced overnight memory consolidation of a finger-tapping sequence more effectively than applying more stimuli with shorter ISIs. The behavioral response was predicted by the number of stimuli with auditory evoked K-complexes relative to the number of stimuli without K-complexes. PTAS stimuli applied at longer ISIs (> 1.25) were associated with a higher likelihood of K-complex responses and fast spindles nesting in the K-complex up-phase. Our results suggest that up-PTAS can be optimized for overnight memory consolidation by introducing ISIs of at least 1.25s. Our study highlights the feasibility of longitudinal at-home PTAS combined with app-based behavioral tasks in healthy participants while leveraging the mechanistic insights such data can offer. Statement of SignificancePhase-targeted auditory stimulation (PTAS) holds great promise for non-invasively enhancing essential functions of slow-wave sleep. However, current protocols have produced variable results and are often confined to laboratory settings. Our study demonstrates the feasibility of a mobile application of automated PTAS and provides experimental evidence that prolonging interstimulus intervals positively affects overnight procedural memory consolidation via K-complexes and coupled sleep spindles. As K-complexes may also be involved in cardiovascular function and brain waste clearance, the proposed protocol optimization may have effects beyond memory enhancement. Together, our findings lay a foundation for a broader application of PTAS in clinical longitudinal studies to improve patient care and recovery outcomes.

neuroscience↗

bioRxiv2024

The Infraslow Fluctuation of Sigma Power During Sleep: Links to Markers of Arousal and Memory Reactivation Across Development

Sleep is both a state of disconnection from the environment and a critical period for restoration. But how does sleep balance responsiveness with the protection of key functions? The infraslow fluctuation of sigma power (ISFS)--the clustering of sleep spindles over 10-100 seconds--is thought to regulate this trade-off in rodents. However, the organization of arousal and memory reactivation markers within the human ISFS and its conservation in younger ages remain unclear. This study characterizes the ISFS from childhood to young adulthood (N = 154; ages 8-26), examining its relationship with functional markers. Results indicate that the ISFS is present across all ages, with frequency, variability, and strength increasing from early to late adolescence. Notably, markers of arousal and memory reactivation are organized within the spindle-rich ISFS peak. The consistent presence and organization of the ISFS suggest it is intrinsic to sleep, with adolescence marking a dynamic window. These insights may guide interventions to promote healthier sleep across development.

neuroscience↗