Biology subjects

Schoenauer, M.

Publications and source records attributed to Schoenauer, M..

8 recordsLinked to original sources

bioRxiv2026

How goals shape naturalistic memories: bias in gaze and narrative recall

Episodic memories are thought to represent information framed by our individual perception and goals, yet personal experiences are hard to evaluate externally. Due to novel methodological advances, we could now trace the development of such goal-shaped memories in a naturalistic experimental setting. We recorded eye-tracking while participants encoded episodic-like memories, and later recorded participants freely narrating their experiences. Naturalistic goal-states were induced by introducing a secret job, which promised to reward participants later for person-based or space-based information. Using computer-vision based semantic segmentation of visual scanning behaviour in movie scenes and data-driven coding of free recall performance, we show that these goals increasingly shift attention during memory encoding and systematically bias narration during retrieval to goal-relevant dimensions. Our findings highlight that we can use data-driven methodology to observe how naturally occurring or induced biases shape how we perceive and remember the world.

neuroscience↗

bioRxiv2026

Learning sculpts microstructure in real time: evidence from dense temporal sampling of diffusion MRI

Learning induces rapid microstructural plasticity in the human brain, yet the precise temporal dynamics of these changes remain unclear. Using dense temporal sampling of diffusion-weighted MRI (DW-MRI) combined with task-based fMRI, we assessed microstructural changes throughout a declarative learning paradigm and subsequent rest. Seventy-four participants (36 females) learned image-location associations across four encoding-retrieval repetitions while undergoing interleaved functional and DW-MRI acquisitions. A matched control group (N=37, 21 females) underwent a similar imaging protocol without learning. Dense sampling of DW-MRI acquisitions (k=2146 across 22 time points in 127 min) revealed that learning-induced mean diffusivity (MD) decreases emerged shortly after learning onset and continued to develop during post-learning rest. The most robust and spatially consistent change was localized to the left middle occipital/temporal gyrus, a region also showing functional activation during encoding and retrieval. Linear mixed-effects modeling further confirmed a significant group-by-time interaction, with MD reductions in the left middle occipital/temporal gyrus emerging as early as {approx}7 min after learning onset, becoming robust by {approx}35-40 min, and persisting throughout the extended post-learning period, while controls showed no changes. Our findings demonstrate that learning-related microstructural plasticity unfolds continuously from encoding to offline consolidation, with learning-induced structural changes emerging in functionally engaged regions. Dense temporal sampling of DW-MRI offers a powerful approach to bridge functional activation and structural remodeling, providing evidence of when and where experience-dependent plasticity occurs during memory formation.

neuroscience↗

bioRxiv2026

Rapid expansion and renormalization of parietal gray matter volume following associative learning

The human brain exhibits rapid structural plasticity following learning, yet its temporal dynamics and behavioral relevance remain elusive, particularly for declarative forms of learning. In this study, we tested whether T1-weighted MRI captures rapid structural reorganization following associative memory formation and whether such changes follow an expansion-renormalization trajectory. We combined three independent datasets (N = 198) to quantify gray matter volume (GMV) changes following an associative memory task using voxel-based morphometry across baseline, 2 h, and 12 h post-learning. We observed transient GMV increases in parietal, lateral occipital, and cerebellar regions at 2 h post-learning, which were no longer detectable relative to baseline by 12 h, consistent with rapid renormalization. Critically, GMV changes in left parietal cortex were associated with memory retention, such that greater maintenance of GMV was associated with better retention. In a separate, spatially distinct effect, sleep facilitated renormalization of GMV in the right parietal cortex, an effect that showed no association with memory retention. Our findings provide evidence that human gray matter undergoes hour-scale changes, reflecting dissociable memory- and sleep-related components.

neuroscience↗

bioRxiv2025

Nightly dynamics of emotional content in dreams

Emotional processing is a crucial adaptive function. Research suggests that sleep, particularly rapid eye movement (REM) sleep, may have a role in processing the emotional load of past events. Notably, dream experiences may offer insight into this nighttime process. Some studies have reported increased emotionality in dreams as the night progresses, possibly reflecting ongoing emotional processing in the sleeping brain. However, findings on how dream affect evolves throughout the night remain mixed. In this study, we investigated how emotional intensity in conscious experiences during sleep changes across the night and sleep stages. Participants (Nsubjects = 20) were subjected to a multiple awakening paradigm, where they were awakened 4-5 times throughout the night and asked to recall their dreams (Ndreams = 61). Additionally, they rated the emotional intensity of their experiences using a structured cued questionnaire. Emotional intensity in dreams increased significantly throughout the night, with late-night dreams being more emotional than dreams collected during earlier sleep. Contrary to our expectation, this increase was not driven by dream reports obtained from REM sleep awakenings. Moreover, late- night dream reports were also significantly longer than those from early sleep, yet the length of the dream reports did not correlate with their emotional intensity. This suggests that the emotionality of dreams is not directly linked to the ability to recall the dream or its narrative complexity. Instead, it could be driven by emotional processes occurring independently throughout the night, or by other factors that regulate our access to dream experiences and their emotional content.

neuroscience↗

bioRxiv2025

Incorporation of complex narratives into dreaming

Reactivation of waking neuronal activity during sleep holds a functional role in memory consolidation. Reprocessing of daytime memory in dreams might aid later memory performance in a similar way. Numerous findings hint at a link between dreaming and sleep-dependent memory processing, however, studies investigating day-residue incorporation in dreaming led to mixed results so far. In this study, we used a naturalistic learning paradigm aimed at biasing dream content by manipulating pre-sleep experience. Participants listened to one of four different audiobooks while falling asleep and were awoken several times during the night to report their dreams. Afterwards, we tested how well they remembered the content of the audiobook. We then asked three blind raters to guess, based solely on anonymized dream reports, which audiobook someone had listened to before experiencing a dream. Our findings show that dreams across the whole night and from both NREM and REM awakenings contain specific information about the content of narratives studied before sleep. Moreover, participants with stronger incorporation of the audiobook in their dreams showed a tendency to recognize more audiobook content across the sleep period. Together, these findings suggest that salient day-time experiences resurface in dreams and that content selected for consolidation during sleep is more strongly incorporated.

neuroscience↗

bioRxiv2024

Spatiotemporal patterns of theta-band activity during rapid-eye movement sleep: a magnetoencephalography analysis

Theta oscillations (4-8 Hz) in frontal cortical regions are present to different degrees across states of consciousness. In sleep, theta is prominent in periods of rapid eye-movement (REM) sleep. Theta has been linked to processes of memory consolidation; however, its mechanistic contribution specifically during REM sleep is not well understood. Interestingly, in the wake state, frontal theta activity increases during effortful cognitive tasks involving executive functions such as working memory, hinting at similarities in circuitry, and potentially, function. The aim of the present work is to create a spatially resolved, whole-brain characterisation of REM oscillatory activity in healthy human subjects, distinguishing theta from neighbouring frequency bands, differentiating substages of REM sleep (phasic and tonic REM), and comparing REM theta to that which is evoked during a working memory task. To that end, we analysed magneto- and electroencephalography (M/EEG) data recorded during overnight sleep in 10 healthy subjects, and similar data from 17 healthy subjects who performed a working memory task, using a novel whole-brain, source-localised MEG approach. Our results show that (i) theta activity has a frontal midline topography that is distinct from those of other prominent frequency bands in REM (delta, alpha, beta), (ii) theta activity in frontal midline regions is best observed within a focused 5-7 Hz range, separating it from occipital alpha activity, (iii) REM theta is dominant over the frontal midline but is also observed in several sub-cortical areas, (iv) theta is more widespread in tonic than phasic REM sleep, and (v) the focused frontal midline theta pattern observed in REM phasic sleep is the most similar of all observed sleep substages to theta evoked by a working memory task. These results enhance our understanding of theta physiology in REM sleep and suggest future targets for research into REMs role in learning and memory.

neuroscience↗

bioRxiv2023

Daytime experiences shape neural activity and dream content in the sleeping brain

Dreams incorporate recent experiences, and memory-related brain activity is reactivated during sleep, suggesting that dreaming, memory consolidation and reactivation are tightly linked. We devised a paradigm to investigate whether memory reprocessing during sleep contributes to dreaming. Participants listened to different audiobooks before falling asleep, introducing dissimilar experiences to be processed at night. We show that audiobook content was reprocessed at the neural level using multivariate pattern analyses. Brain activity during rapid eye movement sleep, particularly in the beta range, carried information about the audiobook. While the amount of neural reinstatement did not correlate with memory retention, global beta power during REM sleep was associated with better memory performance. Moreover, blind raters could determine which audiobook participants had studied based on dream reports. Participants who dreamt of the audiobook also showed stronger neural reinstatement. Reprocessing of pre-sleep experiences during sleep may thus shape our brain activity, our dreams, and our memories.

neuroscience↗

bioRxiv2022

Spindle-dependent memory consolidation in healthy adults: A meta-analysis

Accumulating evidence suggests a central role for sleep spindles in the consolidation of new memories. However, no metaanalysis of the association between sleep spindles and memory performance has been conducted so far. Here, we report meta-analytical evidence for spindle-memory associations and investigate how multiple factors, including memory type, spindle type, spindle characteristics, and EEG topography affect this relationship. The literature search yielded 53 studies reporting 1427 effect sizes, resulting in a small to moderate effect for the average association. We further found that spindle-memory associations were significantly stronger for procedural memory than for declarative memory. Neither spindle types nor EEG scalp topography had an impact on the strength of the spindle-memory relation, but we observed a distinct functional role of global and fast sleep spindles, especially for procedural memory. We also found a moderation effect of spindle characteristics, with power showing the largest effect sizes. Collectively, our findings suggest that sleep spindles are involved in learning, thereby representing a general physiological mechanism for memory consolidation. HighlightsO_LISpindle measures showed a small to medium-sized association with memory performance. C_LIO_LIThis relationship was stronger for procedural memory than declarative memory. C_LIO_LINo moderation effects of spindle type and EEG scalp topography have been observed. C_LIO_LISpindle power emerged as the strongest predictors. C_LIO_LINaps showed similar spindle-related consolidation mechanisms to whole-night sleep. C_LI

neuroscience↗