Biology subjects

Sabo, M.

Publications and source records attributed to Sabo, M..

8 recordsLinked to original sources

bioRxiv2025

Multiple Neural Modules Orchestrate Conflict Processing

Cognitive conflict is a ubiquitous aspect of our daily life, yet its underlying neural mechanisms remain debated. Competing theories propose that conflict processing is governed by either a domain-general system, multiple conflict-specific modules, or an architecture involving partially overlapping mechanisms. The aim of the current study was to clarify how these mechanisms operate at the neural level using a data-driven decoding approach. We analyzed electroencephalogram (EEG) data from 507 healthy participants (ages 20-70) from the Dortmund Vital Study (ClinicalTrials.gov NCT05155397) who completed three conflict tasks: a Change Detection task, a Simon task, and a Stroop task. Using multivariate decoding to distinguish conflict from non-conflict trials, we observed robust within-task decoding across all tasks. However, cross-task decoding revealed shared conflict representations only in specific task pairs. These findings support an account, in which conflict processing relies on partially overlapping neural mechanisms rather than being fully domain-general or entirely task specific. We argue that conflict-related neural processes might be best conceptualized as a continuum of overlap and differentiation, with domain-generality and domain-specificity representing the endpoints of this spectrum. Research Transparency StatementThe authors declare no conflicts of interest. Funding: This work was supported by the International Visiting Scholar Program at The MARCS Institute for Brain, Behaviour, and Development of Western Sydney University (MS), and the Australian Research Council grants DE230100380 (TG) and DP220103047 (MV). Artificial intelligence: Artificial intelligence assisted technologies were utilized solely for language refinement and grammar corrections, ensuring clarity and readability without altering the original content or ideas. Ethics: The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Ethics Committee of the Leibniz Research Centre for Working Environment and Human Factors, Ardeystra{beta}e 67 44139 Dortmund, Germany (IfADo; code A93-3) as detailed in the published study protocol (Gajewski et al., 2022). Preregistration: The current study was not preregistered. However, the dataset used in this manuscript originates from the Dortmund Vital Study, which is registered on ClinicalTrials.gov (NCT05155397). Data: A sample dataset is publicly available at https://doi.org/10.17605/OSF.IO/EDTNM Analysis Scripts: All analysis scripts are publicly available at https://doi.org/10.17605/OSF.IO/EDTNM.

neuroscience↗

bioRxiv2024

Working memory processing boosts the retrieval of existing long-term memory representations

Understanding the interaction between short-term and long-term memory systems is essential for advancing our knowledge of human memory. This study investigates whether working memory processes, specifically attentional prioritization (Experiments 1 and 2) and testing (Experiment 2), can enhance the neural activity associated with recently encoded long- term memories. A total of 86 participants completed a novel three-phase memory task that integrated a traditional long-term memory learning task with a working memory paradigm. In the first phase, participants encoded object-location associations. During the second phase, these associations were reintroduced in a working memory task that manipulated attentional prioritization; participants were required to report the location of the cued object. In the final phase, participants recalled the locations associated with each object. By analyzing both behavioral performance and electroencephalogram (EEG) data collected during this retrieval phase, we found that attentional prioritization in working memory significantly improved long- term memory retrieval, a finding supported by corresponding neural evidence. Additionally, Experiment 2 demonstrated that both prioritization and testing in working memory jointly enhance the neural representation of long-term memories. These findings indicate that working memory processes can dynamically alter the neural patterns underlying long-term memory representations, revealing a more integrated role for working memory in long-term memory consolidation.

neuroscience↗

bioRxiv2024

Structure-based mechanism of RyR channel operation by calcium and magnesium ions

Ryanodine receptors (RyRs) serve for excitation-contraction coupling in skeletal and cardiac muscle cells in a noticeably different way, not fully understood at the molecular level. We addressed the structure of skeletal (RyR1) and cardiac (RyR2) isoforms relevant to gating by Ca2+ and Mg2+ ions (M2+). Bioinformatics analysis of RyR structures ascertained the EF-hand loops as the M2+ binding inhibition site and revealed its allosteric coupling to the channel gate. The intra-monomeric inactivation pathway interacts with the Ca2+-activation pathway in both RyR isoforms, and the inter-monomeric pathway, stronger in RyR1, couples to the gate through the S23*-loop of the neighbor monomer. These structural findings were implemented in the model of RyR operation based on statistical mechanics and the Monod-Wyman-Changeux theorem. The model, which defines closed, open, and inactivated macrostates allosterically coupled to M2+-binding activation and inhibition sites, approximated the open probability data for both RyR1 and RyR2 channels at a broad range of M2+ concentrations. The proposed mechanism of RyR operation provides a new interpretation of the structural and functional data of mammalian RyR channels on common grounds. This may provide a new platform for designing pharmacological interventions in the relevant diseases of skeletal and cardiac muscles. The synthetic approach developed in this work may find general use in deciphering mechanisms of ion channel functions.

molecular biology↗

bioRxiv2023

Remembering what is relevant: how is goal-directed memory reactivation supported by attention and working memory?

Goal-directed memory reactivation involves retrieving the most relevant information for the current behavioral goal. Previous research has linked this process to activations in the fronto-parietal network, but the underlying selection mechanisms remain poorly understood. The current electroencephalogram (EEG) study investigates attention as a possible mechanism supporting goal-directed retrieval. Participants learned associations between objects and two screen locations in an episodic long-term memory experiment. In a following phase, we changed the relevance of some locations to simulate goal-directed retrieval. This was subsequently contrasted to a control condition, in which the original associations remained unchanged. Behavior performance measured during final retrieval revealed faster and more confident responses in the selective vs. neutral condition. At the EEG level, we found significant differences in decoding accuracy, with above-chance effects in the selective cue condition but not in the neutral cue condition. Additionally, we observed a stronger posterior contralateral negativity and lateralized alpha power in the selective cue condition. Overall, these results suggest that attentional selection enhances task-relevant information accessibility, emphasizing its role in goal-directed memory retrieval.

neuroscience↗

bioRxiv2022

Pattern reinstatement and attentional control: overlapping processes during episodic long-term memory retrieval

Episodic long-term memory (eLTM) retrieval involves the reinstatement of neural patterns from the encoding phase. However, recent evidence suggests that comparable effects on cortical activity patterns can also be linked to attentional control processes on the level of memory representations. The current investigation assesses these two processes independently based on alpha-beta-band activity in the electroencephalogram (EEG). During encoding, subjects were presented with an object on a certain position on the screen and had to imagine it on a new position. In each trial, either the task-irrelevant presentation position or the task- relevant imagination position was lateralized. In the retrieval phase, subjects first made an old/new judgement based on centrally presented objects and then reported the imagination position. Pattern reinstatement should be reflected in similar lateralized alpha-beta activity during encoding and retrieval. Conversely, the influence of attentional control processes during retrieval would be associated with the suppression of alpha-beta power contralateral to the to-be-reported imagination position and with the increase of activity contralateral to the irrelevant presentation position. Our results support this latter pattern. This shows that an experimental differentiation between selective attention and pattern reinstatement processes is necessary when studying the neural basis of eLTM retrieval on cortical level.

neuroscience↗

bioRxiv2022

Preparing for the unknown: How working memory provides a link between perception and anticipated action

What mechanisms underlie the transfer of a working memory representation into a higher-level code for guiding future actions? Electrophysiological correlates of attentional selection and motor preparation processes within working memory were investigated in two retrospective cuing tasks. In the first experiment, participants stored the orientation and location of a grating. Subsequent feature cues (selective vs. neutral) indicated which feature would be the target for later report. The oscillatory response in the mu and beta frequency range with an estimated source in the sensorimotor cortex contralateral to the responding hand was used as correlate of motor preparation. Mu/beta suppression was stronger following the selective feature cues compared to the neutral cue, demonstrating that purely feature-based selection is sufficient to form a prospective motor plan. In the second experiment, another retrospective cue was included to study whether knowledge of the task at hand is necessary to initiate motor preparation. Following the feature cue, participants were cued to either compare the stored feature(s) to a probe stimulus (recognition task) or to adjust the memory probe to match the target feature (continuous report task). An analogous suppression of mu oscillations was observed following a selective feature cue, even ahead of task specification. Further, a subsequent selective task cue again elicited a mu/beta suppression, which was stronger after a continuous report task cue. This indicates that working memory is able to flexibly store different types of information in higher-level mental codes to provide optimal prerequisites for all required action possibilities. Highlights* Selectively cueing features results in an overall performance benefit * Feature-based attention is sufficient to form a prospective motor plan * Prospective motor preparation can be initiated ahead of task specification * Retro-active task specification leads to forming of higher-level action codes * Different tasks requirements result in different prospective action plans

neuroscience↗

bioRxiv2021

Aging impairs primary task resumption and attentional control processes following interruptions

Attentional selection of working memory content is impaired after an interruption. This effect was shown to increase with age. Here we investigate how electrophysiological mechanisms underlying attentional selection within working memory differ during primary task resumption between younger and older adults. Participants performed a working memory task, while being frequently interrupted with either a cognitively low- or high-demanding arithmetic task. Afterwards, a retrospective cue (retro-cue) indicated the working memory content required for later report. The detrimental effect of the interruption was evident in both age groups, but while younger adults were more strongly affected by a high-than by a low-demanding interruption, the performance deficit appeared independently of the cognitive requirements of the interruption task in older adults. A similar pattern was found regarding frontal-posterior connectivity in the theta frequency range, suggesting that aging decreases the ability to selectively maintain relevant information within working memory. The power of mid-frontal theta oscillations (4-7 Hz) featured a comparable effect of interruptions in both age groups. How-ever, posterior alpha power (8-14 Hz) following the retro-cue was more diminished by a preceding interruption in older adults. These results suggest an age-related deficit in the atten-tional selection and maintenance of primary task information following an interruption that appeared independent from the cognitive requirements of the interrupting task.

neuroscience↗

bioRxiv2020

Frontal theta and posterior alpha oscillations reflect the reactivation of working memory representations following interruptions

Interruptions (secondary tasks) have been frequently investigated in behavioral studies leading to a deterioration of working memory performance. Yet, the underlying attentional control processes are not sufficiently understood. A lateralized working memory task was frequently interrupted by either a high- or low-demanding arithmetic task and a subsequent retroactive cue indicated the working memory item required for later report. We examined the role of frontal theta (4-7 Hz) and posterior alpha power (8-14 Hz) as correlates for retroactive attentional switches between working memory representations. In particular, highly demanding interruptions decreased primary task performance compared to a control condition without interruption. This was also reflected in decreased frontal theta power and higher posterior alpha power after retro-cue presentation, suggesting decreased attentional control resources. Moreover, reduced alpha lateralization indicated an impaired refocusing on primary task information following the interruption. These results highlight oscillatory mechanisms required for successfully handling the detrimental effects of interruptions.

neuroscience↗