Papers by Diego Mac-Auliffe
Dual-tasking is extremely prominent nowadays, despite ample evidence that it comes with a perform... more Dual-tasking is extremely prominent nowadays, despite ample evidence that it comes with a performance cost: the Dual-Task (DT) cost. Neuroimaging studies have established that tasks are more likely to interfere if they rely on common brain regions, but the precise neural origin of the DT cost has proven elusive so far, mostly because fMRI does not record neural activity directly and cannot reveal the key effect of timing, and how the spatio-temporal neural dynamics of the tasks coincide. Recently, DT electrophysiological studies in monkeys have recorded neural populations shared by the two tasks with millisecond precision to provide a much finer understanding of the origin of the DT cost. We used a similar approach in humans, with intracranial EEG, to assess the neural origin of the DT cost in a particularly challenging naturalistic paradigm which required accurate motor responses to frequent visual stimuli (task T1) and the retrieval of information from long-term memory (task T2), as when answering passengers’ questions while driving. We found that T2 elicited neuroelectric interferences in the gamma-band (>40 Hz), in key regions of the T1 network including the Multiple Demand Network. They reproduced the effect of disruptive electrocortical stimulations to create a situation of dynamical incompatibility, which might explain the DT cost. Yet, participants were able to flexibly adapt their strategy to minimize interference, and most surprisingly, reduce the reliance of T1 on key regions of the executive control network-the anterior insula and the dorsal anterior cingulate cortex-with no performance decrement.</p
Université de Lyon, Apr 6, 2020
Dans nos vies quotidiennes, l'efficacité et la facilité avec laquelle nous agissons dépendent... more Dans nos vies quotidiennes, l'efficacité et la facilité avec laquelle nous agissons dépendent de manière cruciale de notre capacité à nous concentrer sur ce que nous sommes en train de faire. D'un point de vue neuropsychologique, cet état particulier exige que notre cerveau engage à chaque instant les ressources cognitives strictement nécessaires et suffisantes pour la tâche à accomplir, ce qui se manifeste d'un point de vue neuronal par un équilibre subtil entre un ensemble d'activations et d'inhibitions pour garantir que seuls les processus perceptifs, cognitifs et moteurs pertinents pour la tâche soient actifs, à l'exclusion de tout autre. Dans la pratique, pourtant, ces conditions ne sont quasiment jamais réunies, car nous sommes presque toujours distraits d'une façon ou d'une autre, que ce soit par des événements de notre environnement immédiats ou par des pensées spontanées ou bien encore par des tentatives infructueuses de réaliser plusieurs tâches en même temps. Cette thèse cherche à dévoiler les raisons profondes pour lesquelles la distraction a un effet aussi néfaste sur l'attention et sur la performance. Pourquoi est-il si difficile de se concentrer dans un environnement bruyant ? Pourquoi la performance baisse-t-elle dès que nous essayons d'accomplir en même temps deux tâches difficiles qui demandent de l'attention ? Ces questions font l'objet de vifs débats depuis des années, et les mécanismes sous-jacents ont déjà été modélisés de nombreuses manières, mais jusqu'à présent, aucune étude n'avait encore mené l'enquête au niveau d'étude de la dynamique neuronale le plus fin qu'on puisse envisager pratiquement chez un être humain, combinant la précision spatiale de l'IRM fonctionnelle et la précision temporelle de l'électroencéphalographie. Nous avons utilisé des enregistrements EEG intracrâniens - avec une résolution millimétrique toutes les millisecondes - pour examiner dans deux expériences comment les distractions externes et le multitâche interfèrent avec la dynamique optimale d'une tâche d'attention continue et exigeante, et nous avons abordé ces questions dans le contexte naturaliste d'une interaction sociale directe pour garantir que nos conclusions puissent être étendues à des situations communes de la vie quotidienne. Nous avons constaté que l'équilibre très fin entre les activations et les inhibitions neuronales locales nécessaires à la concentration est rompu pendant de courtes périodes - de l'ordre de la seconde - dans les régions clés pour l'attention et le contrôle exécutif, suffisamment pour déséquilibrer l'activité de réseau et nuire à la performance. Ces données apportent un éclairage nouveau pour interpréter bon nombre des défaillances de l'attention que nous rencontrons tous dans nos vies modernes et ouvrent maintenant la voie à de nouvelles techniques pour tenter d'y remédierIn our everyday lives, efficiency and ease crucially depend on our ability to focus on what we are doing at any given time. From a neuropsychological point of view, it means that we are constantly "on‐task", and that our brain always engages resources that are both necessarily and sufficient for the task at hand: at the neural level, this is characterized by a fine balance between activations and inhibitions to ensure that only perceptual, cognitive and motor processes relevant for the task are active, at the exclusion of any other. Yet, practically, such ideal patterns almost never occur because we are almost constantly distracted, most obviously by events in the environment around us, but also by spontaneous thoughts and fruitless attempts to perform several tasks at the same time. This thesis tries to reveal the deep reasons why distraction has such a profound, detrimental effect on attention and performance. Why is it so hard to stay on task in a noisy environment? Why does performance drop when we try to perform two difficult attention‐demanding tasks at the same time? Those questions have already been debated for years, and modelled in many ways, but no study so far had conducted the investigation at the deepest level of the fine neural dynamics that supports our ability to focus. We used the most precise recordings of a living human brain ‐ intracranial EEG recordings with millisecond and milimetric resolution ‐ to examine in two experiments how external distractions and multi‐tasking interfere with the optimal dynamics of a demanding, continuous attention task, and we addressed those questions in naturalistic settings, in the context of a direct social interaction to ensure our conclusions extend to real‐life situations. We found that the tight balance between excitation and inhibition is disrupted in key regions supporting attention and executive control for short periods of time, at the subsecond level, but sufficiently to knock the network off‐balance and impair performance. Altogether, our results provide explanations for many of the failures of attention of our modern lives and pave the way…
ABSTRACTDual-tasking is extremely prominent nowadays, despite ample evidence that it comes with a... more ABSTRACTDual-tasking is extremely prominent nowadays, despite ample evidence that it comes with a performance cost: the Dual-Task (DT) cost. Neuroimaging studies have established that tasks are more likely to interfere if they rely on common brain regions, but the precise neural origin of the DT cost has proven elusive so far, mostly because fMRI does not record neural activity directly and cannot reveal the key effect of timing, and how the spatio-temporal neural dynamics of the tasks coincide.Recently, DT electrophysiological studies in monkeys have recorded neural populations shared by the two tasks with millisecond precision to provide a much finer understanding of the origin of the DT cost. We used a similar approach in humans, with intracranial EEG, to assess the neural origin of the DT cost in a particularly challenging naturalistic paradigm which required accurate motor responses to frequent visual stimuli (task T1) and the retrieval of information from long-term memory (tas...
This article provides an exhaustive description of a new short computerized test to assess on a s... more This article provides an exhaustive description of a new short computerized test to assess on a second-to-second basis the ability of individuals to stay on task, that is, to apply selectively and repeatedly task-relevant cognitive processes. The task (Bron/Lyon Attention Stability Test, or BLAST) lasts around one minute, and measures repeatedly the time to find a target letter in a two-by-two letter array, with an update of all letters every new trial across thirty trials. Several innovative psychometric measures of attention stability are proposed based on the instantaneous fluctuations of reaction times throughout the task, and normative data stratified over a wide range of age are provided by a large (>6000) dataset of participants aged 8 to 70. We also detail the large-scale brain dynamics supporting the task from an in-depth study of 32 participants with direct electrophysiological cortical recordings (intracranial EEG) to prove that BLAST involves critically large-scale ex...
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Papers by Diego Mac-Auliffe