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Schmidig, F. J.

Publications and source records attributed to Schmidig, F. J..

3 recordsLinked to original sources

SleepEEGpy: a Python-based package for the preprocessing, analysis, and visualization of sleep EEG data

Sleep research uses electroencephalography (EEG) to infer brain activity in health and disease. Beyond standard sleep scoring, there is increased interest in advanced EEG analysis that require extensive preprocessing to improve the signal-to-noise ratio, and dedicated analysis algorithms. While many EEG software packages exist, sleep research has specific needs that require dedicated tools (e.g. particular artifacts, event detection). Currently, sleep investigators use different libraries for specific tasks in a fragmented configuration that is inefficient, prone to errors, and requires the learning of multiple software environments. This leads to a high initial complexity, creating a crucial barrier for beginners in sleep research. Here, we present SleepEEGpy, an open-source Python software "wrapper" package to facilitate sleep EEG data preprocessing and analysis. SleepEEGpy builds upon MNE-Python, YASA, and SpecParam tools to provide an all-in-one, beginner-friendly package for comprehensive yet straightforward sleep EEG research including (i) cleaning, (ii) independent component analysis, (iii) detection of sleep events, (iv) analysis of spectral features, and associated visualization tools. A dashboard visualization tool provides an overview to evaluate data and its preprocessing, which can be useful as an initial step prior to detailed analysis. We demonstrate the SleepEEGpy pipeline and its functionalities by applying it to overnight high-density EEG data in healthy participants, revealing multiple characteristic activity signatures typical of each vigilance state. These include alpha oscillations in wakefulness, sleep spindle and slow wave activities in NREM sleep, and theta activity in REM sleep. We hope that this software will be embraced and further developed by the sleep research community, and constitute a useful entry point tool for beginners in sleep EEG research.

neuroscience↗

A visual paired associate learning (vPAL) paradigm to study memory consolidation during sleep

The hippocampus helps transform an experience into an enduring memory by associating its multiple aspects. Sleep improves the consolidation of the newly formed associations, leading to stable long-term memory. Most research on human declarative memory and its consolidation during sleep uses word-pair associations requiring exhaustive learning. Here we present the visual paired association learning (vPAL) paradigm, in which participants learn new associations between images of celebrities and animals. vPAL associations are based on a one-shot exposure that resembles learning in natural conditions. We tested if vPAL can reveal a role for sleep in memory consolidation by assessing the specificity of memory recognition, and the cued recall performance, before and after sleep. We found that a daytime nap improved the stability of recognition memory and discrimination abilities compared to identical intervals of wakefulness. By contrast, cued recall of associations did not exhibit significant sleep-dependent effects. High-density EEG during naps further revealed an association between sleep spindle density and stability of recognition memory. Thus, the vPAL paradigm opens new avenues for future research on sleep and memory consolidation across ages and heterogeneous populations in health and disease.

neuroscience↗

Episodic long-term memory formation during slow-wave sleep

We are unresponsive during slow-wave sleep but continue monitoring external events for survival. Our brain wakens us when danger is imminent. If events are non-threatening, our brain might store them for later consideration to improve decision-making. To test this hypothesis, we examined whether novel vocabulary consisting of simultaneously played pseudowords and translation words are encoded/stored during sleep, and which neural-electrical events facilitate encoding/storage. An algorithm for brain-state dependent stimulation selectively targeted word pairs to slow-wave peaks or troughs. Retrieval tests were given 12 and 36 hours later. These tests required decisions regarding the semantic category of previously sleep-played pseudowords. The sleep-played vocabulary influenced awake decision-making 36 hours later, if targeted to troughs. The words linguistic processing raised neural complexity. The words semantic-associative encoding was supported by increased theta power during the ensuing peak. Fast-spindle power ramped up during a second peak likely aiding consolidation. Hence, new vocabulary played during slow-wave sleep was stored and influenced decision-making days later.

neuroscience↗