European Journal of Neuroscience

Action control allows to respond to relevant stimuli while ignoring the non-relevant stimuli in the surrounding environment. In humans this process is generally studied in conflict tasks, such as the Simon task, in which participants respond with a left or right button press to the non-spatial relevant feature (e.g. the color) of a lateralized stimulus, while ignoring the stimulus position. In this study we used a visual version of the Simon task that we have previsously developed in rats to investigate the involvement of the dorsal striatum, a brain area that is central in action control processes. We tested the effect of excitotoxic lesions of the dorsomedial (DMS) and dorsolateral (DLS) areas in learning to control response interference. We showed that both DMS and DLS lesions negatively impacted rat performances, and this effect strongly depends on task practice. These results suggest an involvement of both areas in learning to manage response conflict.

A proactive mechanism has been postulated to promote successful inhibition (Kenemans, 2015). Specifically, this mechanism is thought to operate before any action demanding or countermanding event has occurred. In the current study, we investigated whether EEG theta power could reflect this mechanism, in a sample of healthy individuals performing a stop-signal paradigm. By comparing frontal theta power preceding failed versus successful stop trials, we tested whether frontal theta is predictive of inhibition success. We hypothesized that proactive cognitive control manifests in frontal theta power preceding a countermanding go-stop event. Our results demonstrate that frontal theta is indeed higher preceding successful as compared to preceding failed stopping events. We also show that frontal theta power preceding stopping events is associated with Stop-Signal Reaction Times (SSRT), with a higher theta being indicative of shorter SSRTs. This association was not present for go-RT. This study may be the first to reveal a relationship between lower frontal theta power and subsequent stopping failure, suggesting thetas role in proactive response inhibition.

The cerebellum is well-established in sub-second motor timing, but its role in supra-second interval timing remains unclear. Here, we investigate how cerebellar output influences time estimation over longer timescales. Rats performed an interval timing task, estimating time based on an auditory cue, while chemogenetic inhibition of the lateral cerebellar nucleus assessed its role in both predictable (externally cued) and unpredictable (internally cued) timing conditions. Cerebellar inhibition produced bidirectional effects: delayed action initiation in predictable trials and premature responses in unpredictable trials. Despite slowed movement, overall task success rates remained unchanged, suggesting a specific impairment in temporal estimation rather than motor execution. These findings demonstrate that the cerebellum integrates motor and cognitive processes for supra-second timing, with differential effects on externally guided and self-generated timing. Our results provide evidence that the lateral cerebellum contributes to supra-second interval timing, supporting its role in adaptive behavior across extended timescales.

The capacity to cancel or adapt planned actions in response to changing environmental demands is essential for navigating our complex world. While past research has shown that an individuals expectations of upcoming movement demands influence the speed of action initiation, the effect this has on subsequent cancellation or adaption of that movement remains unknown. 25 healthy adults completed stop signal tasks and stop change tasks in which biasing cues (e.g., "70% left") accurately indicated the probability that a left, or right button press would be required. As expected, responses that were congruent with the cue were faster than incongruent responses; however, biasing cues had no effect on behavioural or physiological (electromyographical) indices of stopping speed. Stopping latencies were found to be faster in the stop change task than the stop signal task, corroborating other recent work. However, a second experiment (25 healthy adults) which used the same stimuli for both tasks (varying only the instructions), revealed no difference - highlighting the sensitivity of the stop process to stimulus effects, and a common confound in the literature. We also observed that physiological indices of action reprogramming (following a stop) were faster in congruent than incongruent trials. Collectively, these results suggests that preparatory changes that accompany expected movements influence the enaction of movement both prior to, and after stopping, but the stop mechanism itself, remains independent of these preparations. These results inform how action cancellation and adaption are applied in real world environments, where expectations continually interface with our motor plans. HighlightsO_LI* Anticipating a movement increases the speed of its enaction but not subsequent cancellation C_LIO_LI* Expected movements can be reprogrammed more quickly than unexpected movements C_LIO_LI* The latency of action cancellation is highly sensitive to stimulus effects C_LI

Detecting errors in ones own and others actions is likely linked to the discrepancy between intended or expected and produced or observed output. To detect and process the occurrence of salient events seems associated to the release of dopamine, the balance of which is profoundly altered in Parkinsons disease (PD). EEG studies in healthy participants indicate that the occurrence of errors in observed actions triggers a variety of electrocortical indices (like mid-frontal theta activity, error-related delta and the Error Positivity, oPe), that seem to map different aspects of error detection and performance monitoring. Whether these indices are differently modulated by dopamine in the same individual has never been investigated. To explore this issue, we recorded EEG markers of error detection by asking healthy controls (HCs) and PD patients to observe ecological reach-to-grasp a glass actions performed by a virtual arm seen in first person perspective. PD patients were tested under their dopaminergic medication ( on-condition), and after dopaminergic withdrawal ( off-condition). HCs showed a clear oPe and an increase of delta and theta power during the observation of erroneous vs. correct actions. In PD patients, oPe and delta responses were always preserved. Crucially, however, an error-related increase of theta power was found in on but not in off state PD patients. Thus, different EEG error signatures may index the activity of independent systems and error related theta power is selectively modulated by dopamine depletion. Our findings may pave the way to the discovery of dopamine-related biomarkers of higher-order motor cognition dysfunctions that may have crucial theoretical and clinical implications. Significance StatementDopaminergic neurons respond to salient events during performance monitoring. Yet, the impact of dopamine depletion on the human reactivity to observed errors is still unclear. We recorded EEG in patients with Parkinsons Disease (PD) under dopaminergic treatment ( on-condition) and medication withdrawal ( off-condition) while they observed correct and erroneous goal-related actions performed by a virtual limb. Analysis of Error Positivity (oPe) and theta and delta power increase, markers of physiological error-monitoring, indicates that while the formers were intact, the latter was preserved in the on and altered in the off condition. Thus, different EEG markers of error monitoring likely rely on independent circuits. Moreover, mid-frontal theta activity alterations may represent a marker of dopamine-related neurophysiological impairments of higher-order cognition.

Effective interpersonal interaction necessitates constant monitoring and adaptation to others actions, a process known as interpersonal performance monitoring, which is influenced by the dopaminergic system and marked by specific electrocortical signatures. To explore the connection between deficits in interpersonal performance monitoring and altered neural markers, we assessed patients with Parkinsons Disease (PD) performing coordination tasks with a virtual partner (VP) under two conditions: on dopaminergic medication (PD ON) and after withdrawal (PD OFF). In Interactive trials, which required adaptation to the VPs actions, PD OFF performance was impaired compared to PD ON. EEG analysis revealed in PD OFF increased midfrontal Delta-Theta activity during Interactive trials. Higher Delta-Theta synchronization was associated with improved performance, suggesting compensatory mechanisms. Multivariate EEG analysis distinguished Interactive from Cued trials, especially in PD OFF. Our findings highlight dopamine s role in modulating electrocortical markers of interpersonal performance monitor, with significant implications for understanding and treating PD.

Often we have a feeling that we can control effects in the external world through our actions. The role of action processing associated with this implicit form of agency is still not clear. In this study, we used automatic imitation and electroencephalography to investigate neural oscillations associated with action processing and its possible contribution to implicit agency. Brain activity was recorded while participants performed actions (congruent or incongruent with a displayed finger movement) which subsequently triggered an outcome (a tone). We used a time estimation task to measure intentional binding (an index of implicit agency). We observed a decrease of alpha, beta and gamma power for congruent compared to incongruent actions and increased theta power for incongruent compared to congruent actions. Crucially, participants who showed greater intentional binding for congruent versus incongruent actions also presented greater gamma power differences. Alpha, beta and theta power were modulated by congruency but were unrelated to intentional binding. Our study suggests that an increased implicit agency for facilitated actions is associated with changes in gamma power. Our study also contributes to a characterization of neural oscillations in automatic imitation.

Background/AimNerve conduction speed (NCS) abnormalities are considered to be early signs of diabetic peripheral neuropathy. We investigated which determinants impact the NCS and how it is related to markers of metabolic control in children and young adults with diabetes mellitus. MethodFifty-four children aged five to 23 years suffering from type I diabetes mellitus were recruited into this study, which was conducted at the Childrens Hospital of Eastern Switzerland in St Gallen from March 2016 to June 2022. The metabolic control parameters were recorded and a nerve conduction study analyzing three motor nerves and one sensory nerve was performed. The data were compared to a control population of healthy children of the same height, and the height-adjusted NCS (dNCS) was analysed. ResultsFor all four nerves under investigation, a statistically significant drop in the NCS of approximately 5 m/s independent of metabolic control was found, the peroneal nerve being the most sensitive. The NCS of the peroneal nerve correlated significantly negatively with the long-term haemoglobin with bound glucose (HbA1c) and highly significantly negatively with the standard deviation of mean glucose (SD), but there was only a trend with the HbA1c and the time in range (TIR) at the time of neurography. InterpretationAll patients with diabetes mellitus showed a reduced NCS, partly independent of metabolic control. This may be due to a lack of the C-peptide, which regulates critical axonal membrane enzymes. High glucose variability clearly increases the risk of neuropathy, together with but also independently of the mean plasma glucose level.

This report is focusing on a function of the c-Fos protein in an associative, stress-induced memory. The shRNA vector injections were utilised to functionally silence the central amygdala nucleus in adult Wistar rats. Subsequently the operated animals and their control counterparts were screened in a selection of an emotionally-dependent tests and in a few standard behavioral neuroscience tools. Rats from the c-Fos silencing (ShFos) group expressed contra-depressive-like behaviors in Porsolt Swimming Test, spending more time actively searching for escape way then the rats from the control group. ShFos rats also had engaged in a more rapid activity in the Open Field Test, showing a decline in the neo-phobia. Micturition was decreased in shFos animals, indicating a change in the emotionality on an autonomic level. Presented results are showcasing a multi-directional regulation of the behaviors from the central amygdala nucleus by the c-Fos activity.

Relying on evidence for the functional, neurochemical, and spectral parallelism between the late event-related potentials, delta oscillatory brain responses, and the skin conductance response (SCR) system the hypotheses about the existence of the SCR-related brain oscillations and their connectivity with the SCR system have been here suggested. In contrast to classical approach to event-related oscillations which relies on either stimulus- or response-locked time reference, an approach assigned as "oscillatory process-related oscillations" has been introduced. The method enables us to overcome the variability of latency period of the SCR. The hypothesis about the existence of the SCR-related brain oscillations and their delta nature has been confirmed through the grand averaging method. An unexpected finding was the complex nature of the SCR-related oscillations: in addition to the two second EEG segment which was correlated with the SCR system signals they also comprised an initial 200 ms segment uncorrelated with the SCR. The hypothesis about the connectivity between the SCR system and the respective delta brain oscillatory response has been operationalized through a multiple time series regression model. The predictor set consists of the SCR, its first three derivatives, and their mutual interactions. The Monte Carlo test of the causal link between the SCR system signals and the related delta EEG signal demonstrated significance in more than half of the participants. The findings have been considered from the standpoints of the segmental structure of the EEG, monoaminergic signaling and recently emerged the "brain-body dynamic syncytium" hypothesis.

Inhibiting ongoing responses when environmental demands change is a critical component of human motor control. Experimentally, the stop signal task (SST) represents the gold standard response inhibition paradigm. However, an emerging body of evidence suggests that the SST conflates two dissociable sources of inhibition, namely an involuntarily pause associated with attentional capture and the (subsequent) voluntary cancellation of action. The extent to which these processes also occur in other response tasks is unknown. 24 younger (20-35 years) and 23 older (60-85 years) adults completed a series of tasks involving rapid unimanual or bimanual responses to a visual stimulus. A subset of trials required cancellation of one component of an initial bimanual response (i.e., selective stop task; stop left response, continue with right response) or enacting an additional response (e.g., press left button as well as right button). Critically, both tasks involved some infrequent stimuli which bore no behavioural imperative (i.e., they had to be ignored). EMG recordings of voluntary responses during the stopping tasks revealed bimanual covert responses (i.e., muscle activation which was suppressed before a button press ensued), consistent with a pause process, following both stop and ignore stimuli, before the required response was subsequently enacted. Critically, we also observed the behavioural consequences of a similar involuntary pause in trials where action cancellation was not part of the response set (i.e., when the additional stimulus required additional action or ignoring, but not inhibition). The findings shed new light on the mechanisms of inhibition and their generalisability to other task contexts.

BackgroundConscious volition is a broad term and is difficult to reduce to a single empirical paradigm. It encompasses many areas of cognition, including decision-making and empirical studies can be done on these components. This work follows on the seminal work of Libet et al. (1983) which focused on brain activity preceding motor activity and conscious awareness of the intention to move. Previous results have subsequently faced criticism, particularly methods used to average out EEG data over all the trials and the readiness potential not being present on an individual trial basis. This following study aims to address these criticisms. ObjectivesTo use machine learning to investigate brain activity preceding left/right hand movements with relation to conscious intent and motor action. MethodologyThe data collection involved the recreation of the Libet experiment, with electroencephalography (EEG) data being collected. An addition made in this study was the choice between "left" and "right" while observing the Libet clock to subjectively mark the moment of conscious awareness. Twenty-one participants were included (four females, all right-handed). A deep (machine) learning model known as a convolutional neural network (CNN) was used for the EEG data analysis. ResultsSubjectively reported conscious intent preceded the action by 108 ms. The CNN model was able to predict the decision "left" or "right" as early as 4.45 seconds before the action with a test accuracy of 98%. ConclusionThis study has shown motor preparatory processes start up to 4.45 seconds before conscious awareness of a decision to move.

In this study, we used an oddball EEG bicycle paradigm to study how changes in urban environments elicit changes in EEG markers. Participants completed an auditory oddball task while riding in three different cycling lane environments. A low traffic condition where participants rode in a fully separated bike lane alongside a quiet residential street, an intermediate traffic condition where participants rode alongside a busy residential street in a painted lane, and a heavy traffic condition where participants rode alongside fast/heavy traffic on a shared-use path. Relative to the low traffic, heavy traffic was associated with faster reaction time and a trend towards reduced accuracy, and increased N1 amplitude evoked by the standard tones. We attribute this difference in N1 amplitude to different attentional demands evoked by the different traffic conditions. In this fashion, heavy traffic requires greater auditory filtering. Furthermore, we found no differences in P3 amplitude associated with the traffic conditions. We discuss the implications of mobile paradigms to study attention in real-world settings.

Previous studies show that there are differences in native and foreign speech processing (Lev-Ari, 2018) while mixed evidence has been found regarding differences between dialectal and foreign accent processing (see: Adank et al., 2009; Floccia et al. 2006 but see also: Floccia et al., 2009; Girard et al., 2008). Within this field, two theories have been proposed. The Perceptual Distance Hypothesis states that the mechanisms underlying dialectal accent processing are attenuated versions of those of foreign (Clarke & Garrett, 2004). While, the Different Processes Hypothesis argues that the mechanisms of foreign and dialectal accent processing are qualitatively different (Floccia et al, 2009). A recent study looking at single-word EEG data, suggested that there may be flexibility in processing mechanisms (Thomas et al., 2022). The present study deepens this investigation by addressing in which frequency bands native, dialectal and foreign accent processing differ when listening to extended speech. Electroencephalographic data was recorded from 30 participants who listened to dialogues of approximately six minutes spoken in native, dialectal and foreign accents. Power spectral density estimation (1-35 hz) was performed. Linear mixed models were done in frequency windows of particular relevance to discourse processing. Frequency bands associated with phoneme [gamma], syllable [theta], and prosody [delta] were considered along with those of general cognitive mechanisms [alpha and beta]. Results show power differences in the Gamma frequency range. While in higher frequency ranges foreign accent processing is differentiated from power amplitudes of native and dialectal accent processing, in low frequencies we do not see any accent-related power amplitude modulations. This suggests that there may be a difference in phoneme processing for native accent types and foreign accent, while we speculate that top-down mechanisms during discourse processing may mitigate the effects observed with short units of speech.

BackgroundAnodal transcranial direct current stimulation (a-tDCS) has been shown to promote performance improvement of normal individuals in tests of executive function, including tasks that demand sustained attention and inhibitory control. The presumed mechanism is facilitation of prefrontal cortex activation, since a-tDCS is thought to increase cortical excitability. Only a few studies, however, have investigated the effects of inhibitory, cathodal tDCS (c-tDCS) on cognitive tasks, and reported results are often inconsistent. Studies about the effects of c-tDCS upon accuracy and reaction times are particularly scant. Objective/HypothesisThis study assessed the effects of inhibitory c-tDCS over the left dorsolateral prefrontal cortex (l-DLPFC) on the performance of neurologically intact young adults in Stroop and reaction time tests. MethodsSeventeen healthy undergraduate students (ten women) performed Stroop and reaction time tasks after delivery of c-tDCS (1 mA, 20 min) over l-DLFPC or a sham session. All subjects underwent both real and sham sessions, which were separated by an interval of one week. We hypothesized that c-tDCS might lead to an impairment of inhibitory control and attention abilities. ResultsWe found an interference effect on the Stroop task and also a ceiling effect on the reaction Time task. There were no statistically significant performance differences in any of the neuropsychological tests as a function of stimulation condition and/or subject gender. ConclusionsC-tDCS over the l-DLPFC of neurologically intact young individuals did not affect performance in Stroop Test accuracy or in reaction times, irrespective of subject gender. These results raise the possibility that c-tDCS inhibitory effects, well documented for the primary motor area, do not necessarily apply to higher order associative areas. The assumption that c-tDCS has inhibitory effects upon any cortical area, common in clinical trials, should be made with caution.

The study aimed to investigate to what extent blockade of muscarinic receptors affects the speed of endogenous versus exogenous attentional shift times, and how it affects learning induced improvements of attention shift times. Subjects viewed an array of 10 moving clocks and reported the time a clock indicated when cued. Target clocks were indicated by peripheral or central cues, including conditions of pre-cuing. This allowed assessing shift times when attention was pre-allocated, when peripheral cues triggered exogenous attention shifts, and when central cues triggered endogenous attention shifts. In study 1, each subject participated in 2 sessions (scopolamine/placebo), whereby the order of drug intake was counterbalanced across subjects, and subjects were blinded to conditions. Scopolamine/placebo was administered before a psychophysical experiment was conducted. In study 2, the effect of muscarinic blockade on learning induced improvements of attention shift times was investigated. Here scopolamine/placebo was administered immediately after the first (of two) psychophysical sessions, whereby a given subject either received scopolamine or placebo pills. Confirming previous results, we show that pre-cuing resulted in the fastest shift times, followed by exogenous cuing, with endogenous attentional shifts being slowest. Scopolamine application increased attentional shift times across all 3 conditions compared to placebo, but in a dose dependent manner. Additionally, blockade of muscarinic receptors immediately after the first session reduced learning dependent improvement of attention shift times. These results demonstrate that muscarinic receptors play an important role in attention shifting, and they contribute to learning of attention shifting.

Electrophysiological markers of performance monitoring are thought to reflect functioning of dedicated neural networks and neuromodulatory systems. Whether and how these markers are altered in neurological diseases and whether they can reflect particular cognitive deficits remains to be confirmed. Here we first tested whether the frontal medial feedback-related potential, evoked during a trial and error learning task, is changed in early Parkinsons disease patients compared to control subjects. The potential was not changed in amplitude and discriminated negative and positive feedback as in controls. Feedback-related markers in Parkinsons patients also appeared in time-frequency analyses, unaltered in theta (3-7 Hz) band but reduced in beta (20-30 Hz) oscillations for positive feedback. Beta oscillations power appeared to be dramatically globally reduced during the task. Overall, our results show that Beta oscillation markers of performance monitoring captured by EEG are selectively altered in Parkinsons disease patients, and that they are accompanied by changes in task-related oscillatory dynamics. Significance StatementFrontal neural activity evoked by outcomes reveal the functioning of neural systems devoted to flexible behaviours. Modulations of such activity in Parkinsons disease (PD) patients could reflect specific alterations of neural systems and cognitive processing. The goal is to evaluate whether such activity can serve as markers of the disease. Here, using EEG and a trial and error learning protocol, we show that mid-frontal midline performance feedback-related potentials for different types of feedback were similar in controls and early diagnosed PD patients. However, task-related oscillations revealed alterations in the beta range accompanied by more global beta activity alteration in PD compared to controls subjects. This study provides data relevant to the search for non-motor biomarkers in early stages of PD.

Agency, understood as the ability of an organism to control stimuli onset, modulates perceptual and attentional functions. Since stimulus encoding is an essential component of working memory (WM), we conjectured that the perceptual processs agency would positively modulate WM. To corroborate this proposition, we tested twenty-five healthy subjects in a modified-Sternberg WM task under three stimuli presentation conditions: an unpredictable presentation of encoding stimulus, self-initiated presentation of the stimulus, and self-initiation presentation with random-delay stimulus onset. Concurrently, we recorded the subjects electroencephalographic signals during WM encoding. We found that the self-initiation condition was associated with better WM accuracy, and earlier latencies of N100 and P200 evoked potential components representing visual and attentional processes, respectively. Our work demonstrates that agency enhances WM performance and accelerates early visual and attentional processes deployed during WM encoding. We also found that self-initiation presentation correlates with an increased attentional state compared to the other two conditions, suggesting a role for temporal stimuli predictability. Our study remarks on the relevance of agency in sensory and attentional processing for WM.

BackgroundWhile deep brain stimulation (DBS) in the subthalamic nucleus (STN) improves motor functions in Parkinsons disease (PD), it has also been associated with increased impulsivity. MethodsA combined approach of eye-tracking and high-density EEG was used to investigate how high- and low-frequency DBS impact impulsive actions in the antisaccade task in a cohort of ten persons with PD. Computational modelling of the behavioral outcomes allowed a nuanced insight into the effect of DBS on response inhibition and action selection processes. Results: Against our expectations, both 130 Hz- and 60 Hz-DBS improved response inhibition as both resulted in a reduced rate of early reflexive errors. Correspondingly, DBS with both frequencies led to increased desynchronization of beta power during the preparatory period which may be a correlate of anticipatory activation in the oculomotor network. Low-frequency DBS additionally was associated with increased midfrontal theta power, an established marker of cognitive control. While higher midfrontal theta power predicted longer antisaccade latencies in off-DBS state on a trial-by-trial basis, 130 Hz-DBS reversed this relationship. As informed by the computational model, 130 Hz-DBS further led to a shift in the speed-accuracy trade-off causing an acceleration and error-proneness of actions later in the trial. ConclusionsOur results disentangle the impact of DBS on early and late impulsive actions. Only 130 Hz-DBS may disrupt theta-mediated cognitive control mechanisms via medial frontal - STN pathways that are involved in delaying action selection. 60 Hz-DBS may provide beneficial effects on response inhibition without the detrimental effect on action selection seen with 130 Hz-DBS. FundingThis study was supported by the SUCCESS program of Philipps-University Marburg (JW), the Hessian Ministry of Sciences and the Arts, clusterproject: The Adaptive Mind - TAM (FB / AK) and the German Research Foundation (DFG). International Research Training Group 1901 (FB / AK)

Sustained attention allows concentration on a task over long periods of time. This ability fluctuates, with periods of effective focus ( in-the-zone) and periods of increased performance variability and susceptibility to errors ( out-of-the-zone). Little is known about the neural dynamics underlying these states and their fluctuations during sustained attention tasks. To address this, we had thirty young adults perform the gradual onset continuous performance task (gradCPT), during which their EEG and responses were recorded. States of sustained attention (out-vs. in-the-zone) were identified based on the variance time course of participants RT. Out-of-the-zone states were associated with increased errors of commission and reduced perceptual sensitivity compared to in-the-zone states, as expected. Importantly, a significant decline in theta oscillations at mid-prefrontal regions was found during out-of-the-zone (vs. in-the-zone) states over a [~]400 ms period around the transition point between stimuli, and the extent of this decline predicted commission errors and response bias. In addition, individual differences in the variability of midfrontal theta along the task were associated with RT variability. Finally, participants exhibiting greater theta variability showed a more pronounced decline in perceptual sensitivity when being out-of-the-zone and less stable RTs compared to those with lower variability. Our results suggest that states of diminished sustained attention, even during short lapses, are characterized by a reduction in midfrontal theta activity, and that fluctuations in this rhythm covary with fluctuations in attentional control.