Our study investigated the effect of preparatory selective attention on encoding two target items (T1 and T2), causing an attentional blink effect (AB), as observed in previous studies. We altered participants' readiness state on a trial-to-trial basis using informative or uninformative cues for selective attention. Additionally, we varied their overall state of readiness by randomly mixing cue types (mixed cue-context) or presenting them in separate blocks (blocked cue- context). Our findings demonstrated a clear advantage in performance when participants received informative cues compared to uninformative ones in the mixed cue-condition, regardless of the lag between T1 and T2. Notably, in the blocked cue-context condition, cueing benefits were limited to the shortest T1-T2 lag. This suggests that participants proactively prepared to focus on T1 when anticipating conflict, but the extent of this preparation varied between cue-contexts. A heightened state of preparation led to an overinvestment of resources to T1 encoding, which negatively affected T2 encoding. / Thesis / Master of Science (MSc)

Deciding to use lethal force with a firearm is a critical decision that has major implications within society. In order to investigate racial bias in shooting decisions, the current dissertation uses the First-Person Shooter Task (FPST). Previous literature has shown that shooting decisions in this task are made faster and more often towards Black targets when compared to White targets. The relationship between this shooting bias and individual differences in cognitive ability is explored. The FPST was presented in three different conditions, each with trial proportions that varied in level of stereotype congruency (i.e., trials that are congruent with racial stereotypes). A Baseline condition presented an even distribution of Black Armed, Black Unarmed, White Armed, and White unarmed targets. A Mostly Congruent condition presented most (80%) of the Black targets as armed and most (80%) of the White targets as unarmed. A Mostly Incongruent condition presented most of the Black targets as unarmed and the White targets as mostly armed. Working memory, theoretically represented as a system of three separate components, was related to shooting behavior in these FPST conditions. The attentional control component of working memory was shown to be more related to shooting bias when compared to the capacity-related components, especially in the Mostly Incongruent condition (where most trials required making shooting decisions that go against racial stereotype). Study 2 used Confirmatory Factor Analysis to test whether attentional control ability was separate from proactive and reactive control strategy usage. Results showed that the attentional control ability was independent from which attentional control strategy was used. Finally, relating attentional control ability and attentional control strategies to shooting behavior, results showed that people with high attentional control and high proactive control usage were more likely to correctly adjust their expectations of threat in the Mostly Incongruent condition when compared to people with lower ability. People with low attentional control and high proactive control usage were more likely to adjust their expectations of threat based on racial stereotypes. Overall, these findings provide new insight into how cognitive ability interacts with shooting decisions in order to produce racial shooting bias.

Les troubles de l’initiation du mouvement de la maladie de Parkinson sont invalidants et sans solution thérapeutique satisfaisante. Dans ce travail, nous nous intéressons à deux catégories de symptômes, classiquement explorées de façon indépendante : d’un côté, la lenteur à l’initiation du mouvement ou akinésie, et de l’autre, la difficulté à retenir l’initiation d’un mouvement ou impulsivité. En nous appuyant sur des avancées théoriques et méthodologiques récentes, nous tentons de revisiter ces troubles de l’initiation du mouvement en termes de dysfonctionnements exécutifs dans la maladie de Parkinson.Dans ce but, nous avons : 1) recherché les liens entre marqueurs cliniques (akinésie et impulsivité) et troubles du contrôle inhibiteur ; 2) identifié les dysfonctionnements cérébraux associés au moyen de méthodes électroencéphalographiques innovantes permettant de localiser les sources cérébrales et d’observer la dynamique des processus cérébraux ; et 3) sondé l’origine neurochimique de cette fonction à l’aide d’un protocole pharmacologique.Nos résultats suggèrent que l’impulsivité et l’akinésie sont les deux faces d’une même pièce, aux origines d’un dysfonctionnement du contrôle inhibiteur proactif non sélectif. Ils indiquent également que ce contrôle exécutif est sous-tendu par l’activité du noyau sous-thalamique et d’un réseau cortical médian comprenant le précuneus et l’aire motrice supplémentaire. Un rôle du système noradrénergique a également été mis en évidence à l’origine de ces troubles exécutifs. Ces travaux ouvrent donc la voie à de nouvelles perspectives thérapeutiques pour la maladie de Parkinson / Movement initiation disorders in Parkinson’s disease are multifaceted, are debilitating and have no satisfying therapeutic option. On the one hand, slowness and difficulties initiating voluntary movements contribute to akinesia, a cardinal symptom of the disease which is usually considered to be motor in origin and which is not fully alleviated by current medication. On the other hand, difficulties refraining voluntary movements contribute to impulsivity, a frequent side effect of current dopaminergic and neurosurgical therapies. Here, based on systematic analyses of the clinical neuroimaging literature, we suggest that these opposite forms of movement initiation disorders might be executive, not purely motor, in origin.To empirically test this hypothesis, we: 1) related clinical markers of the disease (akinesia and impulsivity) to behavioral indexes of inhibitory control impairment; 2) identified associated cerebral dysfunctions by means of advanced electroencephalographic (EEG) methods; and 3) investigated the neurochemical origin of these dysfunctions by combining pharmacological and cerebral stimulations with EEG recordings.Results suggest that impulsivity and akinesia are the two sides of the same coin. Indeed, they were found to be associated with opposite inhibitory control disorders, and dysfunctions of subthalamic cortical loops involving medial executive areas. Importantly, it was also found that restoring normal behavior and normal activity within these loops by means of deep brain stimulation depends on the level of noradrenergic tonus, opening the way for new therapeutic approaches for Parkinson’s disease

Les troubles exécutifs de la maladie de Parkinson sont invalidants et sans solution thérapeutique satisfaisante. La raison est liée au fait que les fonctions exécutives sont difficiles à appréhender, tant au niveau de leur modélisation cognitive qu'anatomo-fonctionnelle ou neurochimique. Ici, nous nous appuyons sur des avancées théoriques et méthodologiques récentes pour revisiter ces troubles exécutifs. Nous nous intéressons à une fonction, récemment mise en évidence, destinée à verrouiller par anticipation le déclenchement de toute action en situation d'incertitude : le contrôle proactif de l'inhibition non sélective de l'action. Notre hypothèse directrice est que son dysfonctionnement est susceptible de générer une grande variété de troubles exécutifs. Nous avons : 1) recherché les liens entre marqueurs cliniques et troubles du contrôle proactif ; 2) identifié les dysfonctionnements cérébraux associés au moyen de méthodes électroencéphalographiques innovantes combinées à l'enregistrement des effets de la stimulation du noyau sous-thalamique ; et 3) sondé l'origine neurochimique de cette fonction. Nos résultats suggèrent qu'un dysfonctionnement de l'inhibition proactive n'engendre pas uniquement des troubles impulsifs mais explique également des comportements hypo-productifs comme l'akinésie. Ils indiquent que ces troubles ne sont pas d'origine dopaminergique et qu'ils sont liés au dysfonctionnement de l'activité du cortex frontal médian et du noyau sous-thalamique. Ces travaux ouvrent la voie à de nouvelles perspectives thérapeutiques pour la maladie de Parkinson et à une meilleure appréhension de la clinique d'autres pathologies / Executive impairments in Parkinson’s disease are debilitating and have no satisfying therapeutic option. This is partly due to the fact that executive functions are difficult to investigate from cognitive, neuro-functional and neurochemical standpoints. Here, we build on recent theoretical and methodological improvements to revisit executive impairments. We are interested in a function that consists in locking in advance movement initiation mechanisms in the face of uncertainty: proactive control of non-selective inhibition of action. Our leading hypothesis is that dysfunction of proactive inhibitory control could generate widespread and heterogeneous executive impairments. We thus: 1) tried to relate clinical markers of the disease to behavioral indexes of proactive control impairment; 2) identified the associated cerebral dysfunctions by means of advanced electroencephalographic methods and manipulation of deep brain stimulation of the subthalamic nucleus; and 3) investigated the neurochemical origin of this function. Our results suggest that impulsivity is not the only outcome of inhibitory impairment. Disorder of proactive inhibitory control may also account for hypo-productive behaviors such as akinesia. Results also indicate that this mechanism is of non-dopaminergic origin and relies on medial frontal and subthalamic activity. This work opens the way for new therapeutic approaches for Parkinson’s disease as well as a better understanding of clinical symptoms observed in others diseases

Wie sich die Sprachwahrnehmung an ständig eingehende Informationen anpasst, ist eine Schlüsselfrage in der Gedanken- und Gehirnforschung. Die vorliegende Dissertation zielt darauf ab, zum Verständnis von Anpassungen an die Sprecheridentität und Sprachfehler während der Sprachverarbeitung beizutragen und unser Wissen über die Rolle der kognitiven Kontrolle bei der Sprachverarbeitung zu erweitern. Zu diesem Zweck wurden ereigniskorrelierte Potentiale (EKPs, englisch: event-related potentials, ERPs) N400 und P600 in der Elektroenzephalographie (EEG) analysiert. Die vorliegende Arbeit befasste sich insbesondere mit der Frage nach der Anpassung an die Sprecheridentität bei der Verarbeitung von zwei Arten von Sprachfehlern (Xu, Abdel Rahman, & Sommer, 2019), und untersuchte die proaktive Anpassungen, die durch die Erkennung von Sprachfehlern (Xu, Abdel Rahman, & Sommer, 2021) und durch die Sprecher(dis)kontinuität über aufeinanderfolgende Sätze in Situationen mit mehreren Sprechern ausgelöst wurden (Xu, Abdel Rahman, & Sommer, 2021, in press). Die Ergebnisse zeigten, dass unterschiedliche Sprachverarbeitungsstrategien entsprechend der Sprecheridentität von Muttersprachlern oder Nicht-Muttersprachlern und zwei verschiedenen Arten von Sprachfehlern angepasst wurden, was sich in unterschiedlichen N400- und P600-Effekten widerspiegelte. Darüber hinaus kann die Erkennung von Konflikten (Sprachfehler) und Sprecher(dis)kontinuität über aufeinanderfolgende Sätze hinweg eine proaktive kognitive Kontrolle erfordern, die die Verarbeitungsstrategien für den folgenden Satz schnell anpasst, was sich in bisher nicht gemeldeten sequentiellen Anpassungseffekten in der P600-Amplitude manifestierte. Basierend auf dem DMC Modell (Braver, 2012; Braver, Gray, & Burgess, 2007) und dem Überwachungsmodell der Sprachverarbeitung (van de Meerendonk, Indefrey, Chwilla, & Kolk, 2011) schlage ich vor, dass die P600-Amplitude nicht nur reaktive Anpassungen manifestiert, die durch Konflikterkennung ausgelöst werden, nämlich die klassischen P600-Effekte, die eine erneute Analyse der Sprachverarbeitung widerspiegeln, sondern auch proaktive Anpassungen in der Überwachung der Sprachverarbeitung, die Mechanismen der kognitiven Kontrolle von Aufmerksamkeit und Gedächtnis beinhalten. / How language perception adapts to constantly incoming information is a key question in mind and brain research. This doctoral thesis aims to contribute to the understanding of adaptation to speaker identity and speech error during speech processing, and to enhance our knowledge about the role of cognitive control in speech processing. For this purpose, event-related brain potentials (ERPs) N400 and P600 in the electroencephalography (EEG) were analyzed. Specifically, the present work addressed the question about adaptation to the speaker’s identity in processing two types of speech errors (Xu, Abdel Rahman, & Sommer, 2019), and explored proactive adaptation initiated by the detection of speech errors (Xu, Abdel Rahman, & Sommer, 2021) and by speaker (dis-)continuity across consecutive sentences in multi-speaker situations (Xu, Abdel Rahman, & Sommer, 2021, in press). Results showed that different speech processing strategies were adapted according to native or non-native speaker identity and two different types of speech errors, reflected in different N400 and P600 effects. In addition, detection of conflict (speech error) and speaker (dis-)continuity across consecutive sentences engage cognitive control to rapidly adapt processing strategies for the following sentence, manifested in hitherto unreported sequential adaptation effects in the P600 amplitude. Based on the DMC model (Braver, 2012; Braver, Gray, & Burgess, 2007) and the monitoring theory of language perception (van de Meerendonk, Indefrey, Chwilla, & Kolk, 2011), I propose that the P600 amplitude manifests not only reactive adaptations triggered by conflict detection, i.e., the classic P600 effect, reflecting reanalysis of speech processing, but also proactive adaptations in monitoring the speech processing, engaging cognitive control mechanisms of attention and memory.