Biology subjects

Staudigl, T.

Publications and source records attributed to Staudigl, T..

At least 19 recordsLinked to original sources

bioRxiv2026

Action Sequences Structure Human Memory Reactivation

Episodic memory formation is not a passive process but emerges from sequences of actions through which we engage with our environment. Yet, how these action sequences interact with the neural dynamics underlying human memory formation and retrieval remains poorly understood. Here, we investigated whether coordinated gaze shifts, one of the major exploratory actions in humans, structure the reactivation of memories. Participants learned multiple action sequences by pairing images with distinct real-world gaze shifts while we simultaneously recorded EEG and motion tracking data. During subsequent retrieval, the recalled gaze sequences acted as a direct behavioral readout of memory performance. Representational similarity analyses revealed that the reactivation of image memories was precisely timed to recalled gaze shifts within each sequence. Crucially, only correctly executed, but not incorrectly executed gaze shifts elicited significant reactivation of the corresponding image class, directly linking neural reactivation to retrieval success. These findings suggest that exploratory actions are fundamental components of episodic memories, not incidental accompaniments: self-initiated movements can serve as temporal anchors of memory reactivation that predict retrieval success. By investigating memory through natural behavior, our work provides an ecologically grounded perspective on human cognition, revealing that species-typical actions such as gaze shifts are essential to, rather than obstacles for, understanding memorys neural basis.

neuroscience↗

bioRxiv2026

The breathing cycle gates memory reactivation during human NREM sleep

Sleep-dependent memory consolidation relies on the precise coordination of slow oscillations (SOs) and spindles. Respiration has recently emerged as a potential pacemaker of this coordination, but whether it thereby shapes memory processes during sleep remains unknown. Here, we used closed-loop targeted memory reactivation (TMR) in humans (N = 25) to target auditory cues to either each participants SO-spindle-favored respiratory phase (preferred-phase cueing) or the opposite phase (antiphase cueing). Preferred-phase cueing enhanced associative memory relative to antiphase cueing and promoted more precise spindle alignment to SO up-states. Respiratory phase also shaped the timing of reactivation: preferred-phase cues aligned category-specific reactivation with the ensuing SO up-state, whereas antiphase cues delayed reactivation to later SO-spindle complexes occurring at a similar respiratory phase. These findings identify breathing as an endogenous timing signal that organizes the SO-spindle windows in which memory reactivation unfolds, thereby structuring sleep-dependent consolidation.

neuroscience↗

bioRxiv2026

Non-invasive tracking of ripple-like activity during human sleep using MEG

Hippocampal ripples are considered a key mechanism of sleep-dependent memory consolidation. In humans, however, their direct investigation has relied on invasive recordings from patients with epilepsy, because EEG provides limited access to fast activity from deep medial temporal structures. Here, we tested whether source-resolved magnetoencephalography can reveal physiologically meaningful ripple-like activity during NREM sleep in healthy humans. These events showed hallmarks expected of sleep ripples: they were most prominent in medial temporal regions and embedded within slow oscillation (SO)-spindle dynamics, occurring preferentially during SO up-states and spindle centers. To test mnemonic relevance, we combined sleep MEG with targeted memory reactivation, in which learning cues were replayed during sleep. TMR improved memory performance, and later remembered cues preferentially recruited medial temporal ripple-like events alongside cortical spindles. Ripple-like events also coincided with enhanced item-specific reactivation during successful TMR. Together, these findings establish MEG as a non-invasive window onto hippocampo-cortical memory dynamics during sleep.

neuroscience↗

bioRxiv2025

Low-frequency brain oscillations reflect the dynamics of the oculomotor system: a new perspective on subsequent memory effects

Neural activity and eye movements are two well-established predictors of memory performance in humans. Successful memory formation is typically associated with reduced alpha/beta power (i.e., the alpha/beta subsequent memory effect) and an increased number of eye movements. However, the functional relevance of these two memory correlates has primarily been investigated in isolation, leaving their coupling and combined contribution to memory formation largely unknown. Here, we address this gap through four experiments involving simultaneous eye-tracking and scalp or intracranial electroencephalography recordings while participants viewed scenes either freely or under varying levels of visual constraint. Across experiments and cohorts, we identified the degree of visual exploration, rather than subsequent memory performance, as the consistent and robust modulator of alpha/beta power reductions. Going beyond correlations, manipulating eye movements dissociated alpha/beta power reductions from memory. Combined with the finding that saccade parameters predicted the dynamics of alpha/beta activity, our results directly link alpha/beta activity to the oculomotor system. Moreover, we show that the accumulation of saccades over time accounted for the reduced alpha/beta power, resembling the pattern typically observed after stimulus onset. Our work demonstrates that neglecting eye movements results in an incomplete understanding of the alpha/beta subsequent memory effect. Together, the evidence points at alpha/beta activity directly reflecting eye movements, and only indirectly, memory formation. The current study thus bridges two lines of previous research and advocates for new perspectives on the specific interpretation of the alpha/beta subsequent memory effect and on the function of alpha/beta activity in general.

neuroscience↗

bioRxiv2025

Respiratory coordination of excitability states across the human wake-sleep cycle

While the respiratory rhythm is increasingly recognized as a key modulator of oscillatory brain activity across the wake-sleep cycle in humans, very little is known about its influence on aperiodic brain activity during sleep. This broadband activity indicates spontaneous fluctuations in excitation-inhibition (E:I) balance across vigilance states and has recently been shown to systematically covary across the respiratory cycle during waking resting state. We used simultaneous EEG and respiratory recordings over a full night of sleep collected from N = 23 healthy participants to unravel the nested dynamics of respiration phase-locked excitability states across the wake-sleep cycle. We demonstrate a prominent phase shift in the coupling of aperiodic brain activity to respiratory rhythms as participants were transitioning from wakefulness to sleep. Moreover, respiration-brain coupling became more consistent both across and within participants, as interindividual as well as intraindividual variability systematically lessened from wakefulness and the transition to sleep towards deeper sleep stages. Our results suggest that respiration phase-locked changes in E:I balance conceivably add to sleep stage-specific neural signatures of REM and NREM sleep, highlighting the complexity of brain-body coupling during sleep.

neuroscience↗

bioRxiv2025

Respiration shapes the neural dynamics of successful remembering in humans.

Respiration has been shown to impact memory retrieval, yet the neural dynamics underlying this effect remain unclear. Here, we investigated how respiration shapes both behavioral and neural expressions of memory retrieval by re-analyzing an existing dataset where scalp electroencephalography and respiration recordings were acquired while participants (N = 18) performed an episodic memory task. Our results unveil that respiration influences retrieval-related power fluctuations in the /{beta} band and concomitant memory reactivation. Specifically, we found that both key neural signatures of successful remembering were co-modulated during exhalation, with the strength of the interaction between respiration and reactivation processes being associated with memory performance. Together, these findings suggest that respiration may act as a scaffold for episodic memory retrieval in humans by coordinating the neural conditions that support effective remembering. Significance statementRecent evidence suggests that respiration may shape neural dynamics underlying various cognitive processes. In this study, we identify respiration as a potential pacemaker for memory retrieval by showing that key neural signatures of effective remembering--namely, decreases in /{beta} power and the reactivation of previously encoded neural representations--are tightly synchronized with the respiratory cycle. Notably, the strength of this respiration-brain coupling is associated with individual memory performance, underscoring the critical role and functional significance of brain-body interactions in supporting cognitive functions.

neuroscience↗

bioRxiv2025

Thalamic oscillations distinguish natural states of consciousness in humans

Natural states of consciousness are thought to be regulated by deep brain structures such as the thalamus. However, very little is known about the underlying electrophysiology in humans. Here, using a rare opportunity to directly record from the human thalamus, we identify a hitherto-unreported brain-state-specific oscillation of approximately 19-45 Hz. This oscillation is present only during Rapid Eye Movement (REM) sleep and wakefulness, while being absent during Non-REM sleep. The 19-45 oscillation further distinguishes REM sleep microstates, co-occurring with bursts of eye movements, and is specific to the Central Thalamus, a structure implicated in causing global brain state transitions. The discovery of a distinct oscillatory signature in the Central Thalamus that distinguishes conscious states opens up avenues to further investigate thalamic contributions to states of consciousness in humans and potentially to refine interventions to treat disorders of consciousness.

neuroscience↗

bioRxiv2024

Entorhinal grid-like codes for visual space during memory formation

Eye movements, such as saccades, allow us to gather information about the environment and, in this way, can shape memory. In non-human primates, saccades are associated with the activity of grid cells in the entorhinal cortex. Grid cells are essential for spatial navigation, but whether saccade-based grid-like signals play a role in human memory formation is currently unclear. Here, human participants underwent functional magnetic resonance imaging (fMRI) and continuous eye gaze monitoring while studying scene images. Recognition memory was probed immediately thereafter. Results revealed saccade-based grid-like codes in the left entorhinal cortex while participants studied the scene images, a finding that was replicated with an independent data set reported here. The grid-related effects were time-locked to activation increases in the frontal eye fields. Most importantly, saccade-based grid-like codes were associated with recognition memory, such that grid-like codes were lower the better participants performed in subsequently recognizing the scene images. Collectively, our findings suggest an entorhinal map of visual space that is timed with neural activity in oculomotor regions, supporting memory formation.

neuroscience↗

bioRxiv2023

Imperceptible gamma-band sensory stimulation enhances episodic memory retrieval

Enhanced gamma activity (30-100Hz) coincides with the successful recall of episodic memories, but it remains unknown whether this oscillatory activity is a cause or a consequence of the retrieval process. To address this question, we asked human participants to complete a paired associates memory task while undergoing sensory stimulation (at 65Hz, 43.3Hz and 32.5Hz). We observed that 65Hz and 32.5Hz sensory stimulation enhances recall compared to a baseline condition without stimulation. No similar effect was observed following 43.3Hz stimulation. Notably, while almost all participants could perceive 32.5Hz and 43.3Hz sensory stimulation, only a small proportion of participants ([~]10%) could perceive the 65Hz visual flicker, suggesting 65Hz sensory stimulation acts as an imperceptible intervention to enhance recall. To understand the dual action of 65Hz and 32.5Hz sensory stimulation on recall, we built three pyramidal-interneuronal network gamma (PING) models and drove them using the same stimulation protocols as in the behavioural task. The behavioural results could be reproduced by stimulating an endogenous [~]32Hz oscillation, but not by stimulating an endogenous [~]65Hz oscillation nor by stimulating a network without an endogenous oscillation. These results suggest that imperceptible 65Hz sensory stimulation enhances recall by harmonically entraining an endogenous [~]32.5Hz oscillation. Based on these findings, we propose that "slow" gamma oscillations play a causal role in episodic memory retrieval.

neuroscience↗

bioRxiv2023

Respiration shapes sleep-oscillations and memory reactivation in humans.

The beneficial effect of sleep on memory consolidation relies on the precise interplay of slow oscillations (SOs) and spindles. However, whether these rhythms are orchestrated by an underlying pacemaker has remained elusive. Here, we tested whether respiration, which has been shown to impact brain rhythms and cognition during wake, shapes memory reactivation by modulating sleep-related oscillations and their interplay in humans. We recorded scalp EEG and respiration throughout an experiment in which participants acquired associative memories before taking a nap. Our results reveal that respiration strongly modulates the emergence of sleep oscillations. Specifically, SOs, spindles as well as their interplay (i.e., coupled SO_spindle complexes) systematically increase towards inhalation peaks. Moreover, the strength of respiration-SO_spindle coupling is linked to the extent of memory reactivation during SO_spindles. Our results identify respiration as a potential pacemaker for memory consolidation in humans and highlight the critical role of brain-body interactions during sleep.

neuroscience↗

bioRxiv2023

Memory reactivation of real-world spatial orientation revealed by human electrophysiology.

Memory consolidation relies on the reactivation of previous experiences during sleep. The precise interplay of sleep-related oscillations (slow oscillations, spindles and ripples) is thought to coordinate the information flow between relevant brain areas, with ripples mediating memory reactivation. However, in humans empirical evidence for a role of ripples in memory reactivation is lacking. Here, we investigated the relevance of sleep oscillations and specifically ripples for memory reactivation during human sleep using targeted memory reactivation (TMR). Intracranial electrophysiology in epilepsy patients and scalp EEG in healthy participants revealed that elevated levels of SO-spindle activity promoted the read-out of TMR induced memory reactivation. Importantly, spindle-locked ripples recorded intracranially from the medial temporal lobe were found to be instrumental for memory reactivation to unfold during non-rapid eye movement (NREM) sleep. Our findings establish ripples as key-oscillation in human systems consolidation and emphasize the importance of the coordinated interplay of the cardinal sleep oscillations.

neuroscience↗

bioRxiv2023

Electrophysiological signatures of veridical head direction in humans

Information about heading direction is critical for navigation as it provides the means to orient ourselves in space. However, given that veridical head direction signals require physical rotation of the head and most human neuroimaging experiments depend upon fixing the head in position, little is known about how the human brain is tuned to such heading signals. To address this, we asked fifty-two healthy participants undergoing simultaneous EEG and motion tracking recordings (split into two experiments) and ten patients undergoing simultaneous intracranial EEG and motion tracking recordings to complete a series of orientation tasks in which they made physical head rotations to target positions. We then used a series of forward encoding models and linear mixed-effects models to isolate electrophysiological activity that was specifically tuned to heading direction. We identified a robust posterior central signature that predicts changes in veridical head orientation after regressing out confounds including sensory input and muscular activity. Both source localisation and intracranial analysis implicated the medial temporal lobe as the origin of this effect. Subsequent analyses disentangled head direction signatures from signals relating to head rotation and those reflecting location-specific effects. Lastly, when directly comparing head direction and eye gaze-related tuning, we found that the brain maintains both codes while actively navigating, with stronger tuning to head direction in the medial temporal lobe. Together, these results reveal a taxonomy of population-level head direction signals within the human brain that is reminiscent of those reported in the single units of rodents.

neuroscience↗

bioRxiv2022

Cortico-ocular coupling in the service of episodic memory formation

Encoding of visual information is a necessary requirement for most types of episodic memories. In search for a neural signature of memory formation, amplitude modulation of neural activity has been repeatedly shown to correlate with and suggested to be functionally involved in successful memory encoding. We here report a complementary view on why and how brain activity relates to memory, indicating a functional role of cortico-ocular interactions for episodic memory formation. Recording simultaneous magnetoencephalography and eye tracking in 35 human participants, we demonstrate that gaze variability and amplitude modulations of alpha/beta oscillations (10-20 Hz) in visual cortex covary and predict subsequent memory performance between and within participants. Amplitude variation during pre-stimulus baseline was associated with gaze direction variability, echoing the co-variation observed during scene encoding. We conclude that encoding of visual information engages unison coupling between oculomotor and visual areas in the service of memory formation.

neuroscience↗

bioRxiv2022

Saccades are coordinated with directed circuit dynamics and stable but distinct hippocampal patterns that promote memory formation

During natural viewing, humans explore their environment by moving the eyes - a process that involves saccades to guide attention and shape memory. Saccades are controlled by visuo-oculomotor regions and are known to impact medial temporal lobe processing, but the circuit dynamics in humans are unclear. Here, we asked which of the functional routes between the visual cortex, frontal eye fields, and the hippocampus facilitates memory encoding during visual exploration and whether saccades affect neural representations. Forty-eight human participants underwent functional magnetic resonance imaging (fMRI) and continuous monitoring of eye gaze while studying scenes and performing a recognition memory test thereafter. We discovered saccade-related excitatory coupling from the visual cortex and frontal eye fields towards the hippocampus, independent of memory. This was complemented by hippocampal inhibition of the visual cortex that determined whether participants would later remember or forget. Moreover, saccades were associated with overall stable but distinct hippocampal voxel patterns during memory formation and the degree of pattern distinctiveness positively scaled with inhibition along the hippocampus-to-visual cortex route. This suggests that eye movements are timed to the orchestration of circuit connectivity and neural representations, setting the stage for memory formation.

neuroscience↗

bioRxiv2022

Rhythmic interactions between the mediodorsal thalamus and prefrontal cortex precede human visual perception

The thalamus is much more than a simple sensory relay. High-order thalamic nuclei, such as the mediodorsal thalamus, exert a profound influence over animal cognition. However, given the difficulty of directly recording from the thalamus in humans, next-to-nothing is known about thalamic and thalamocortical contributions to human cognition. To address this, we analysed simultaneously-recorded thalamic iEEG and whole-head MEG in six patients (four female, two male; plus MEG recordings from twelve healthy controls) as they completed a visual detection task. We observed that the phase of both ongoing mediodorsal thalamic and prefrontal low-frequency activity was predictive of perceptual performance. Critically however, mediodorsal thalamic activity mediated prefrontal contributions to perceptual performance. These results suggest that it is thalamocortical interactions, rather than cortical activity alone, that is predictive of upcoming perceptual performance and, more generally, highlights the importance of accounting for the thalamus when theorising about cortical contributions to human cognition.

neuroscience↗

bioRxiv2021

The human thalamus orchestrates neocortical oscillations during NREM sleep.

A hallmark of non-rapid eye movement sleep is the coordinated interplay of slow oscillations (SOs) and sleep spindles. Traditionally, a cortico-thalamo-cortical loop is suggested to coordinate these rhythms: neocortically-generated SOs trigger spindles in the thalamus that are projected back to neocortex. Here, we used intrathalamic recordings from human epilepsy patients to test this canonical interplay. We show that SOs in the anterior thalamus precede neocortical SOs (peak -50 ms), whereas concurrently-recorded SOs in the mediodorsal thalamus are led by neocortical SOs (peak +50 ms). Sleep spindles, detected in both thalamic nuclei, preceded their neocortical counterparts (peak -100 ms) and were initiated during early phases of thalamic SOs. Our findings indicate an active role of the anterior thalamus in organizing sleep rhythms in the neocortex and highlight the functional diversity of thalamic nuclei in humans. The thalamic coordination of sleep oscillations could have broad implications for the mechanisms underlying memory consolidation.

neuroscience↗

bioRxiv2020

Endogenous memory reactivation during sleep in humans is clocked by slow oscillation-spindle complexes.

Sleep is thought to support memory consolidation via reactivation of prior experiences, with particular electrophysiological sleep signatures (slow oscillations (SOs) and sleep spindles) gating the information flow between relevant brain areas. However, empirical evidence for a role of endogenous memory reactivation (i.e., without experimentally delivered memory cues) for consolidation in humans is lacking. Here, we devised a paradigm in which participants acquired associative memories before taking a nap. Multivariate decoding was then used to capture endogenous memory reactivation during non-rapid eye movement (NREM) sleep in surface EEG recordings. Our results reveal reactivation of learning material during SO-spindle complexes, with the precision of SO-spindle coupling predicting reactivation strength. Critically, reactivation strength (i.e. classifier evidence in favor of the previously studied stimulus category) in turn predicts the level of consolidation across participants. These results elucidate the memory function of sleep in humans and emphasize the importance of SOs and spindles in clocking endogenous consolidation processes.

neuroscience↗

bioRxiv2020

Saccadic modulation of neural activity in the human anterior thalamus during visual active sensing

Humans and other primates explore visual scenes by active sensing, using saccadic eye movements to relocate the fovea and sample different bits of information multiple times per second. Saccades induce a phase reset of ongoing neuronal oscillations in primary and higher-order visual cortices and medial temporal lobe. As a result, neuron ensembles are shifted to a common state at the time visual input propagates through the system (i.e., just after fixation). The extent of the brains circuitry modulated by saccades is not yet known. Here, we evaluate the possibility that saccadic phase reset impacts the anterior nuclei of the thalamus (ANT). Using rare recordings in the human thalamus of three surgical patients, we found saccade-related phase concentration, peaking at 3-4 Hz, coincident with suppression of Broadband High-frequency Activity (BHA; 80-180 Hz). Our results provide evidence for saccade-related modulation of neuronal excitability dynamics in the ANT, consistent with the idea that these nuclei are engaged during visual active sensing. These findings show that during real-world active visual exploration neural dynamics in the human ANT, a part of extended hippocampal-diencephalic system for episodic memory, exhibit modulations that might be underestimated in typical passive viewing.

neuroscience↗