Biology subjects

Beste, C.

Publications and source records attributed to Beste, C..

6 recordsLinked to original sources

bioRxiv2026

Distilling Trial-Level EEG Variability into Participant Representations: Neurophysiologically Constrained Graph Learning in ADHD

Extracting stable individual-level representations from noisy and variable trial-wise EEG remains a major challenge in computational cognitive neuroscience. We developed a spatiotemporal graph attention network to analyze Go/NoGo EEG from children and adolescents with and without ADHD. The framework combines ERP-informed temporal windows, phase-synchrony graph priors, and trial-to-participant transfer learning, making both information routing and representation geometry explicitly testable. The model learned reproducible attention trajectories, yet ADHD and control participants did not differ reliably in spatial attention allocation. Instead, group-related structure emerged in compact participant-level embeddings that distilled trial-level variability and retained discriminative information beyond convolutional representations. Performance exceeded a convolutional neural network comparison, but the central advance is methodological: neurophysiologically constrained graph learning can reveal where diagnostically relevant information emerges within the analytical pipeline. This provides a framework for developing auditable cognitive-neurophysiological markers of neurodevelopmental variation.

neuroscience↗

bioRxiv2025

Differential alterations in peripheral tryptophan pathways in methamphetamine versus MDMA users are linked to their contrasting psychiatric symptoms

Methamphetamine (METH, "Crystal Meth") and 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") are two types of substituted amphetamines that share structural-chemical similarities but exhibit contrasting acute and chronic effects including addictive liability. Tryptophan (TRY) pathways are involved in pleiotropic physiological functions at the interface of brain-body connections. Preclinical evidence suggests that amphetamines may modulate these pathways and, thus, indirectly influence brain functions via persistent alterations of peripheral metabolites. However, little is known about alterations of TRY-related metabolites in the blood and their clinical implications in chronic users of MDMA and METH. Hence, we characterized serum levels of TRY-related metabolites in a comparative cross-sectional study including n=36 chronic MDMA users, n=33 chronic METH users, and n=71 sex-matched, stimulant-naive healthy controls (Ntotal=140). An ultra- high performance liquid chromatography-mass spectrometry method was used to determine TRY metabolites. Combining metabolite levels, metabolic ratios, and network analysis we found robust evidence of divergent pathway alterations between METH and MDMA users. Chronic METH use was particularly associated with a depletion of serum TRY and serotonin levels, and a general activation of kynurenine pathways, while chronic MDMA use was linked to a selective activation of the OH-kynurenine metabolic branch. Metabolite changes were associated with the severity of psychopathology in the depression and psychosis domains across groups. Altogether, our findings demonstrate differential changes of serum TRY pathways in chronic MDMA and METH users. Persistent alterations of these pathways might contribute to the contrasting clinical profile of the substances and constitute a peripheral dimension of neurochemical plasticity with relevant implications for therapeutic targets.

biochemistry↗

bioRxiv2024

Reward processing in children with Affective Dysregulation

IntroductionAffective dysregulation (AD) in children is characterized by irritability, anger, and frequent intense temper outbursts. Considerable evidence implies altered processing of frustration about missed rewards, but few studies investigated the preceding and thus potentially predictive reward anticipation and initial delivery processing in children with AD. MethodsA total of 103 children aged 8 to 12 years (50 with AD and 53 without AD) were examined during a monetary reward anticipation task with event-related potential (ERP) components resolving reward anticipation (cue-CNV [Contingent Negative Variation]) and reward delivery phases (Reward Positivity and Feedback-Related Negativity). All components were analyzed by repeated measures ANOVA. Regression analyses also evaluated the associations between those ERP components and dimensional AD symptoms. ResultsChildren with AD showed attenuated anticipatory reward processing compared to No-ADs. The CNV at fronto-central site (FCz) showed a significant group effect (No-AD>AD, p=0.017). Post-hoc test showed that this group difference was stronger for the cue monetary condition (monetary cue: p=.007, d=0.56, verbal cue: p=.901, d=0.16), and that only the No-AD group showed a significant difference between conditions (p<0.001). No significant effects were obtained for the delivery phase. Regression analysis showed that a reduced anticipatory CNV at FCz significantly explained AD symptoms, and that anger/irritability and anxiety/depressive symptoms predicted a reduced anticipatory CNV at FCz. ConclusionThis neurophysiological characterization of reward anticipation and delivery in children with AD demonstrates altered neural activity in AD during anticipation of reward rather than following the delivery (or omission) of the reward itself. Our results highlight that altered reward anticipation in AD can occur outside frustration-prone tasks or settings, and underline the important role of both anger/irritability and anxiety/depressive symptoms in the pathophysiology of AD for atypical reward anticipation.

neuroscience↗

bioRxiv2024

Neurophysiological Dynamics of Metacontrol States: EEG Insights into Conflict Regulation

Understanding the neural mechanisms underlying metacontrol and conflict regulation is crucial for insights into cognitive flexibility and persistence. This study employed electroencephalography (EEG), EEG-beamforming and directed connectivity analyses to explore how varying metacontrol states influence conflict regulation at a neurophysiological level. Metacontrol states were manipulated by altering the frequency of congruent and incongruent trials across experimental blocks in a modified flanker task, and both behavioral and electrophysiological measures were analyzed. Behavioral data confirmed the experimental manipulations efficacy, showing an increase in persistence bias and a reduction in flexibility bias during increased conflict regulation. Electrophysiologically, theta band activity paralleled the behavioral data, suggesting that theta oscillations reflect the mismatch between expected metacontrol bias and actual task demands. Alpha and beta band dynamics differed across experimental blocks, though these changes did not directly mirror behavioral effects. Post-response alpha and beta activity were more pronounced in persistence-biased states, indicating a neural reset mechanism preparing for future cognitive demands. By using a novel artificial neural networks method, directed connectivity analyses revealed enhanced inter-regional communication during persistence states, suggesting stronger top-down control and sensorimotor integration. Overall, theta band activity was closely tied to metacontrol processes, while alpha and beta bands played a role in resetting the neural system for upcoming tasks. These findings provide a deeper understanding of the neural substrates involved in metacontrol and conflict monitoring, emphasizing the distinct roles of different frequency bands in these cognitive processes.

neuroscience↗

bioRxiv2020

Neurophysiological coding of statistical and deterministic rule information

Humans are capable of acquiring multiple types of information presented in the same visual information stream. It has been suggested that at least two parallel learning processes are important during learning of sequential patterns - statistical learning and rule-based learning. Yet, the neurophysiological underpinnings of these parallel learning mechanisms in visual sequences are not fully understood. To differentiate between the simultaneous mechanisms at the single trial level, we apply a temporal EEG signal decomposition approach together with sLORETA source localization method to delineate whether distinct statistical and rule-based learning codes can be distinguished in EEG data and can be related to distinct functional neuroanatomical structures. We demonstrate that concomitant but distinct aspects of information coded in the N2 time window play a role in these mechanisms: mismatch detection and response control underlie statistical learning and rule-based learning, respectively, albeit with different levels of time-sensitivity. Moreover, the effects of the two learning mechanisms in the different temporally decomposed clusters of neural activity also differed from each other in neural sources. Importantly, the right inferior frontal cortex (BA44) was specifically implicated in statistical learning, confirming its role in the acquisition of transitional probabilities. In contrast, rule-based learning was associated with the prefrontal gyrus (BA6). The results show how simultaneous learning mechanisms operate at the neurophysiological level and are orchestrated by distinct prefrontal cortical areas. The current findings deepen our understanding on the mechanisms how humans are capable of learning multiple types of information from the same stimulus stream in a parallel fashion.

neuroscience↗

bioRxiv2018

How non-veridical perception drives actions in healthy humans - Evidence from Synaesthesia

We continually perform actions driven by our perception and it is commonly held that only objectively perceived changes within the real world affect behaviour. Exceptions are usually only made for clinical conditions associated with hallucinations, where objectively non-existent percepts can influence behavior. Using synaesthesia as a model condition, we show that even in healthy populations irrelevant non-veridical precepts exert an effect on action. By non-veridical we refer to stimulus dimensions that are only subjectively perceived to be there. Applying electrophysiological (EEG) methods, we show that although these examined peculiarities are perceptual in nature, not primarily perceptual processes underlie the effects of irrelevant non-veridical perceptions on actions. Rather, high-order processes linking perceptions and motor control in medial frontal cortices reflect the underlying mechanism how irrelevant non-veridical perceptions modulate behaviour. Our results challenge assumptions about the determinants of healthy human behaviour but can be embedded within existing frameworks detailing perception action interactions.

neuroscience↗