The central theme of the present thesis revolves around the exploration of similarities and differences in brain activity patterns invoked by the component processes underlying mnemonic, executive and attentional functions. The primary aim was to identify and functionally characterize commonly recruited brain regions in terms of shared component processes, which has been a largely neglected area of research in cognitive neuroscience. The vast majority of functional brain imaging investigations of cognition has focused on delineating differences between cognitive functions or processes, with the purpose of isolating the unique functional neuroanatomy that underlies specific cognitive domains. By contrast, the present thesis builds on the results from three imaging studies that focused primarily on detecting commonalities in functional brain activity across different forms of memory processes. In study I, the imaging data from two positron emission tomography (PET) experiments were re-analyzed to identify common activation patterns associated with nine different memory tasks incorporated across the experiments, three each separately indexing working memory, episodic memory, and semantic memory. A generic prefrontal cortex (PFC) network involving discrete subregions of the left hemisphere located in ventrolateral (BA 45/47), dorsolateral (BA 9/44/46), and frontopolar (BA 10) sectors of PFC, as well as a midline portion of the frontal lobes, encompassing the dorsal part of the anterior cingulate cortex (ACC) (BA 24/32), was conjointly recruited across all tasks. In study II, we used a novel mixed blocked/event-related functional magnetic resonance imaging (fMRI) design, which enables separation of brain responses associated with different temporal dynamics to further investigate commonalities of neural activation across working memory, episodic memory, semantic memory, and attention/vigilance. A similar set of common PFC regions, as that discovered in Study I, was found to elicit overlapping brain activity across all memory tasks, with a subset of regions also activated in the attention/vigilance task. Furthermore, the task-induced brain activity was dissociated in terms of the temporal profiles of the evoked neural responses. A common pattern of sustained activity seen across all memory tasks and the attention task involved bilateral (predominantly right-lateralized) ventrolateral PFC (BA 45/47), and the dorsal ACC (BA 24/32), which was assumed to reflect general processes of attention/vigilance. A pattern of sustained activity elicited in all memory tasks, in the absence of attention-related activity, involved the right frontopolar cortex (BA 10), which was assumed to reflect control processes underlying task set maintenance. In addition, common transient activation evoked in the memory tasks relative to the attention task was found in the dorsolateral (BA 9/44) and ventrolateral (BA 47) PFC, the superior parietal cortex (BA 7), and cerebellum. In study III, a mixed fMRI design was used to assess the degree of common brain activity associated with increased executive demand, which was independently manipulated within episodic and working memory. Unitary control modulations involved a shared tonic executive component subserved by fronto-striatal-cerebellar circuitry, assumed to govern top-down context processing throughout task periods, and a stimulus-synchronous phasic component mediated by the intraparietal sulcus (BA 7), assumed to support dynamic shifting of the ‘focus of attention’ among internal representations. Collectively, the theoretical implications of shared neural mechanisms are discussed, with a special focus on human memory and its multifaceted relationships with attention and executive control functions. Finally, the presented imaging data are used to outline a tentative hierarchical neurocognitive model that attempts to give an account of how different unitary component processes might work together during cognitive task performance.

Les caractéristiques de l’enfant à la maternelle prédisent le succès des transitions à travers les premières années scolaires ainsi que la poursuite académique à l’âge de 22 ans. Les habiletés en mathématiques et langagières à la maternelle sont étroitement liées au rendement scolaire. Cependant, il est également important de tenir compte du rôle de l’autocontrôle et de la maîtrise de soi dans la réussite académique. Spécifiquement, la capacité de suivre des instructions et travailler de manière autonome pourrait faciliter l’adaptation des enfants en milieu scolaire. La présente thèse examine la valeur potentielle de cibler l’engagement scolaire à la maternelle, sous forme d’orientation vers la tâche, pour améliorer l’ajustement académique des enfants au cours du primaire. Une première étude, a examiné si l’engagement scolaire à la maternelle est associé à un meilleur niveau de réussite scolaire et d’ajustement psychosocial à la quatrième année du primaire. Les résultats suggèrent que les habitudes de travail dès l’entrée à l’école représentent des prédicteurs robustes du rendement académique quatre ans plus tard. Un plus haut niveau d’engagement prédit également moins de comportements externalisés et de victimisation par les pairs en quatrième année. Ces résultats sont demeurés significatifs suite au contrôle statistique des habilités en mathématique, langagières et socio-émotionnelles des enfants ainsi que de facteurs de risques familiaux. Une deuxième étude a examiné l’origine de l’engagement scolaire au primaire. Cette étude a permis d’observer que le niveau de contrôle cognitif des enfants d’âge préscolaire représente un prédicteur significatif de l’engagement scolaire à la maternelle. Ces résultats suggèrent l’existence d’une continuité développementale du contrôle cognitif de la petite enfance à la maternelle, et que celle-ci pourrait servir de base pour le développement de bonnes habitudes de travail au primaire. Finalement dans une troisième étude, des analyses centrées sur la personne ont été effectués. Trois sous-groupes d’enfants ont été identifiés dans notre échantillon. Les résultats obtenus indiquent des trajectoires d’engagement bas, moyen et élevé respectivement, au primaire. Le faible contrôle cognitif et les facteurs de risques familiaux ont prédit l’appartenance à la trajectoire d’engagement faible. Dans l’ensemble, les résultats de ces trois études soulignent l’importance de tenir compte de l’engagement dans les évaluations de la maturité scolaire à la maternelle. Cette recherche pourrait également informer le développement de programmes d’interventions préscolaires visant à augmenter la préparation scolaire ainsi que la réduction des écarts au niveau de la réussite académique des enfants. / How children begin school is an important predictor of their eventual academic attainment. Although kindergarten knowledge of numbers and vocabulary represent robust indicators of children’s readiness to learn at school entry, theory and research suggest that self-directed learning skills are also important for helping children meet the challenges of the elementary school classroom. In the present thesis, three papers examine the potential benefit of targeting classroom engagement skills in terms of task-orientation and industriousness to improve children’s academic outcomes. In Paper 1, kindergarten classroom engagement skills were found to predict later academic performance and psychosocial adjustment. These results remained significant even after adjusting for kindergarten mathematics, verbal, and attention skills and established child and family risk factors. Paper 2 addresses the origins of classroom engagement and shows that early childhood cognitive control skills represent robust predictors of school entry classroom engagement skills. These findings suggest that developmental continuity in cognitive control may culminate in better school entry engagement skills. Finally in Paper 3, person-centered analyses were used to identify three subgroups of children showing low, moderate, and high patterns of engagement across elementary school. Belongingness to the low engagement trajectory was predicted by early childhood cognitive control skills and parental risk factors. Taken together these results underscore the importance of considering classroom engagement skills in school readiness assessments. This research also has implications for the development of early interventions designed to bolster school readiness in order to circumvent later academic and social impairments.

Aging, also in the absence of pathological conditions, is associated with cognitivedecline, especially in so called fluid abilities, such as episodic memory andexecutive functions. Due to an ongoing demographic shift, a larger part of thepopulation will reach higher ages, and more people will be affected by age-relatedcognitive decline. Finding ways of counteracting this development have the potentialof having large benefits for both individuals and society. It has long beenknown that living in environments that are rich in terms of cognitive challengescan affect cognitive ability in old age. In this regard, intervention studies in whichthe amount of cognitive stimulation is manipulated can therefore generate insightsto the causality of such effects in specific cognitive functions. Cognitive trainingas means to counteract negative effects of aging on cognition has received a lot ofscientific interest in the last decades.This focus of this thesis is cognitive training interventions, which is studiedfrom several perspectives. In Study i, the aim was to investigate the extent towhich executive functions can be strengthened by training in younger and olderadults, and to which degree such training generalize to other measures of cognition.Although a large body of research has been investigating training of workingmemory and executive functions in recent years, the results are diverse, and fewhave been targeting executive functions broadly with training programs based ontheoretical models of executive functions. Study i showed that despite a broadtraining program targeting three executive functions (updating, shifting and inhibition),it did not lead to transfer beyond the very near in old adults. The youngerhowever showed transfer effects to measures of working memory.In Study ii, the focus was on studying how the effects survive across time.There is limited knowledge about long-term effects of process-based training andthe results showed that the training effect was stable after 1.5 years, while only thenearest transfer effect was still significant in both younger and older adults.Study iii focused on individual factors affecting gain and maintenance thereofin a sample of older individuals. We used a strategy-based intervention focusingon episodic memory performance with a number-consonant mnemonic which is amnemonic for memorizing digit-codes. A different set of predictors was observedfor baseline episodic memory performance and training gain. Those that are betteroff in terms of episodic memory performance, also gain more in the episodic memorycriterion task. Further, a higher rate of processing speed was also important.Lastly, better verbal knowledge also influence gain beyond the other factors. Theresults have both theoretical implications regarding how plastic cognitive functionsare, and practical, in terms of how to best design training programs. / Över hela världen blir vi äldre. År 2050 kommer en femtedel av jordens befolkningvara 60 år eller äldre, att jämföra med en knapp tiondel år 1950. Det är förstås enpositiv utveckling men en åldrande befolkning innebär också att vi står inför flerautmaningar. En sådan rör det kognitiva åldrandet. Vi vet att åldrande kan leda tillnedgång i vissa kognitiva förmågor, såsom det episodiska minnet samt exekutivafunktioner. Episodiskt minne är vår förmåga att komma ihåg upplevda händelserknutna till tid och rum. Exekutiva funktioner är ett begrepp som inbegriper vårförmåga att hålla en plan aktiv medan vi utför den, utan att distraheras av tankareller externa störningsmoment. Genom att studera effekter av träning hos yngreoch äldre vuxna på sådana kognitiva funktioner kan vi få kunskap om till vilkengrad de kan förbättras och om denna förbättringspotential är olika beroende påålder. Vi vet sedan tidigare att människor som under sin livstid lever ett kognitivtstimulerande liv också till viss del är skyddade mot nedgång i kognition underåldrandet. Träningsstudier kan ge kunskap om kausaliteten i sådana fynd.Studie i i denna avhandling behandlar träning av exekutiva funktioner föryngre och äldre vuxna. Träningsprogrammet konstruerades utefter en teoretiskmodell som beskriver exekutiva funktioner som bestående av förmågan att inhiberastörande stimuli eller överlärda responser, förmågan att uppdatera informationi arbetsminnet, och förmågan att skifta mellan att utföra olika uppgifter. Resultatenvisade att de yngre kunde generalisera träningseffekten också till otränadearbetsminnesuppgifter, medan de äldre endast visade förbättring på otränade uppgiftersom hade stora likheter med de tränade.I Studie ii undersöktes hur mycket av träningseffekterna som kvarstod ettoch ett halvt år efter träningen. Resultaten visade att både för yngre och äldreså kvarstod effekten på tränade uppgifter samt en av uppgifterna som hade stortöverlapp med träningsuppgifterna, för både unga och äldre.I Studie iii studerades ett strategibaserat träningsprogram för episodisktminne. Fokus låg på att undersöka vilka individuella kognitiva faktorer sompåverkar förbättring som följd av träning. Resultaten visade att de med högre förmågai kognitiv bearbetningshastighet samt verbal förmåga var de som hade bästförutsättningar för förbättring.Resultaten från dessa studier är av både teoretisk relevans i och med att deökar förståelsen för träningsbarheten av exekutiva funktioner, samt har praktiskrelevans för utformning av träningsprogram.

Text in Afrikaans / In this study quantitative research is employed to determine if cognitive control therapy can successfully be utilized in a group situation to alleviate cognitive deficiency in learners with Attention-Deficit/Hyperactivity Disorder (ADHD). Learners with ADHD often do not gain from traditional play- and psychotherapy due to the fact that they do not possess the required cognitive structure necessary to support successful learning. Many of these learners do not receive sufficient assistance and support due to a shortage of government supported educational psychological aid. An empirical investigation of limited scope was performed to establish whether cognitive deficiencies can be alleviated by means of applying cognitive control therapy in a group situation. A one-group pretest-posttest design was utilized where the same group of subjects was studies before and after the experimental treatment. The results indicate that the cognitive control therapy program resulted in a considerable change. / Educational Studies / M. Ed. (Voorligting)

La mémoire de travail et le contrôle cognitif sont des construits proches ; on suppose généralement qu'une forte capacité en mémoire de travail est associée à un contrôle cognitif efficace. Cette hypothèse a des implications importantes pour la cognition humaine et apporte une explication élégante à la corrélation fréquemment reportée entre mémoire de travail et intelligence fluide. En revanche, les difficultés d'opérationnalisation et de mesure du contrôle cognitif rendent l'hypothèse difficile à tester. Un modèle récent du contrôle cognitif, le modèle à Deux Mécanismes de Contrôle (DMC), offre une solution à ce problème : ce modèle propose l'existence de deux mécanismes de contrôle cognitif distincts et permet de les opérationnaliser de façon efficace. La littérature prédit que l'un de ces deux mécanismes, le contrôle proactif, devrait être lié à la mémoire de travail. L'objectif de cette thèse était de tester l'existence d'une relation entre les différences inter-individuelles en mémoire de travail et la tendance à mettre en place un mécanisme de contrôle proactif. Cette relation a été testée sous quatre axes de travail : 1) en utilisant de nouveaux paradigmes expérimentaux pour mesurer la tendance à utiliser le contrôle proactif, 2) grâce à des tâches classiques de contrôle cognitif choisies pour leur sensibilité au contrôle proactif, 3) à travers une approche par imagerie cérébrale incluant électro-encéphalographie et imagerie par résonance magnétique fonctionnelle, et 4) en tant que facteur explicatif de la relation entre mémoire de travail et intelligence fluide. Dans l'ensemble, nos résultats n'ont pas permis de soutenir l'idée que la capacité en mémoire de travail est directement liée à la tendance à utiliser un mécanisme de contrôle proactif ; les données suggèrent plutôt un avantage général en faveur des participants à forte capacité en mémoire de travail dans toutes les situations. / The constructs of working memory and cognitive control are conceptually close; a high working memory capacity is hypothesized to be associated with an efficient cognitive control. This hypothetical association has large implications for human cognition and provides an elegant explanation for the frequently reported relationship between working memory capacity and fluid intelligence. However, the difficulty in operationalizing and measuring cognitive control makes this hypothesis hard to test. One model of cognitive control, the Dual Mechanisms of Control (DMC) framework, constitutes a possible solution to this problem: the model proposes two distinct mechanisms of cognitive control which can be efficiently operationalized and studied. There is reason to believe that one of these two mechanisms, proactive control, is specifically related to working memory capacity. The objective of the present research work was to assess the relationship between individual differences in working memory capacity and the tendency to use proactive control. This relationship was tested in four steps: 1) by using innovative measures of the tendency to use proactive control, based on newly developed paradigms, 2) with classic cognitive control tasks sensitive to proactive control, 3) with a neuroimaging approach using electro-encephalography and functional magnetic resonance imaging, and 4) by testing whether the use of proactive control explains the relationship between working memory and fluid intelligence. Overall, our results did not support the idea that working memory capacity is uniquely related to the tendency to use proactive control; the data were more consistent with a general advantage of participants with a high working memory capacity in all situations.

L’objectif de ce travail de thèse a été d’avancer dans les connaissances des mécanismes de contrôle cognitif sous-tendant les détériorations et fluctuations d’attention soutenue chez les patients souffrant de schizophrénie et les sujets sains. Dans ce but, nous avons combiné mesures comportementales, électrophysiologiques et subjectives. Nos résultats montrent une préservation des capacités d’attention soutenue chez les patients ainsi qu’une origine distincte des variations d’attention soutenue chez les patients. Les détériorations sont sous-tendues par une diminution du mode de contrôle réactif chez les patients et du mode proactif chez les témoins. De plus, différents précurseurs des lapses attentionnels ont été mis en évidence chez les patients selon l’état attentionnel. Les variations d’attention soutenue sont principalement liées à une diminution des ressources attentionnelles chez les patients, alors que chez les témoins, en fonction de l’état attentionnel, elles pourraient également être liées à un désengagement, une défaillance du contrôle cognitif. / The purpose of this project was to gain more knowledge about cognitive control mechanisms underlying deteriorations and fluctuation of sustained attention in schizophrenia and healthy participants. To that end, we combined the use of behavioral, electrophysiological (event-related potentials and functional connectivity) and subjective measures. Our results revealed spared sustained attention in schizophrenia and a distinct patterns of sustained attention changes in schizophrenia. Deteriorations are underlined by a decrease of reactive mode of cognitive control in patients and by a decrease of proactive mode in controls. Our results also highlighted slightly distinct patterns of precursors of lapses in sustained attention in schizophrenia according to the attentional state. Sustained attention changes are associated with resource depletion in patients, whereas in healthy participants, according to attentional state, they could also be caused by disengagement of cognitive control.

In this study the impact of a board game as parent guidance strategy to reinforce Cognitive Control Therapy (CCT) in the home environment of a child with ADHD was explored. The influence of such a board game, based on the principles of CCT, on multiple contexts of the child’s existence - therapeutic and family contexts - was also investigated. There were two reasons for involving the parents in therapy. Firstly, children with an attention problem are situated within contexts and the effect of ADHD can permeate to the home and school environments. Secondly, for Cognitive Control Therapy (CCT) to be successful, it needs to be sustained by frequent repetition. It was hypothesized that sustainability of the effect of CCT should rise substantially after introduction of the board game, as the child and the parent can reinforce the principles of CCT by using it, even without being able to attend a session. The board game was designed by using the principles for game development as articulated by Dodge. A case study was then conducted by using a mixed methods approach, where quantitative and qualitative data were obtained. Data collection strategies consisted of quantitative methods in the form of the Cognitive Control battery (pre and post test), and the Copeland Symptoms checklist. Qualitative strategies included parental feedback, qualitative data during therapy sessions (observations and therapeutic notes) and a semi-structured interview with the mother. Data was collected before, after and during the intervention. The intervention consisted of individual therapy with the participant, parent guidance and parallel implementation of the designed board game by the parents with the child-participant. The quantitative data (from the CCB and the Copeland Symptoms Checklist) from the post test indicated that sensitivity towards distractions remains a concern, and that parental implementation of a board game (incorporating elements of CCT) with a child can possibly have a slightly negative effect on cognitive control functioning. However, the scope of this case study does not allow direct correlations to be drawn between the parental input and the child’s cognitive control functioning. It does point to the possibility of heeding caution when implementing a board game to reinforce CCT principles by a parent. Conversely, the findings from the study also indicated that family relations improved. Five qualitative insights emerged: i) increased ability to distinguish between relevant versus irrelevant information in the participant; ii) increase in organizational thought in the therapeutic situation and at home; iii) improved communication between parent and child, resulting in improved skills to maintain discipline; iv) improved interaction among family members; and v) transfer of skills to the mother. The study found that the greatest contribution of the board game appears to be the improvement experienced in the family context – probably as a result of increased interaction among family members and attention focused on the problem. / Dissertation (MEd (Educational Psychology))--University of Pretoria, 2007. / Educational Psychology / MEd / unrestricted

There are large overlaps in cognitive deficits occurring in attention deficit disorder (ADD) and neurodevelopmental disorders like neurofibromatosis type 1 (NF1). This overlap is mostly based on clinical measures and not on in-depth analyses of neuronal mechanisms. However, the consideration of such neuronal underpinnings is crucial when aiming to integrate measures that can lead to a better understanding of the underlying mechanisms. Inhibitory control deficits, for example, are a hallmark in ADD, but it is unclear how far there are similar deficits in NF1. We thus compared adolescent ADD and NF1 patients to healthy controls in a Go/Nogo task using behavioural and neurophysiological measures. Clinical measures of ADD-symptoms were not different between ADD and NF1. Only patients with ADD showed increased Nogo errors and reductions in components reflecting response inhibition (i.e. Nogo-P3). Early perceptual processes (P1) were changed in ADD and NF1. Clinically, patients with ADD and NF1 thus show strong similarities. This is not the case in regard to underlying cognitive control processes. This shows that in-depth analyses of neurophysiological processes are needed to determine whether the overlap between ADD and NF1 is as strong as assumed and to develop appropriate treatment strategies.

La crise de boulimie est vécue comme une perte de contrôle par les patientes atteint de boulimie (BN), d’anorexie avec crise de boulimie (ANB) et d’hyperphagie boulimique. Si ces patientes présentent effectivement des performances dégradées aux tâches neuropsychologiques évaluant les mécanismes du contrôle cognitif modulant la tendance à s’engager dans des actions sans prendre en compte leurs conséquences, la méthodologie employée ne permet pas de séparer les mécanismes propres à la crise de boulimie de ceux plus généraux du trouble. La comparaison des performances à une batterie de tâches évaluant les différents mécanismes du contrôle cognitif, de patientes BN, ANB, anorexiques restrictives avec des sujets sains en conditions alimentaire et neutre révèle que les crises de boulimie seraient liées à un contrôle cognitif perturbé par un surplus attentionnel vers les stimuli alimentaires lors de la réalisation de tâches intuitives, déséquilibrant la modulation de ce contrôle sur la tendance générale à choisir des options risquées ou immédiates explicites. En modifiant la séquence d’ingestion des aliments au cours de la crise de boulimie pour augmenter leurs compétences de contrôle faisant défaut en situation alimentaire, des patientes répondant faiblement à la thérapie comportementale et cognitive ont diminué spontanément de 44% les quantités ingérées et la moitié d’entre elles a guéri. Si ces résultats nécessitent confirmation par une étude en imagerie fonctionnelle, ils montrent l’utilité de modéliser finement les mécanismes de traitement automatique de l’information pour améliorer les thérapies actuelles / Binge eating episodes are experienced by bulimic (BN), anorexic binging subtype (ANB) and binge eating disorder (BED) patients as periods of loss of control. This feeling is corroborated by the impaired behavioral performances to neuropsychological tasks assessing cognitive control but these results do not allow separating the mechanisms that are specific to the binge from those related to the whole psychopathology of the disorder. The goal of this thesis is to identify these mechanisms, to build a model explaining the occurrence of binges and to design and test a new behavioral intervention to treat directly binges. BN, ANB and anorexic restrictive subtype patients as well as matched controls underwent a battery of neuropsychological tasks performed in food and neutral conditions. Comparison of performances between the two conditions exhibited an impairment in food condition of intuitive mechanisms of cognitive control due to a higher attention paid to food stimuli. This results in an unbalanced modulation of the general trend to choose risky or immediate options when explicitly mentioned. Another group of ANB, BN and BED patients modified the sequence of ingestion of foods during the binge in order to train themselves to recruit the impaired mechanisms of cognitive control identified at the previous step. They experienced a spontaneous reduction of 44% of food intake during binges and half of them recovered from binges. While these results need to be confirmed by a functional neuroimaging study, they stress the importance of modeling precisely the instantaneous automated mechanisms that mediate behavior in order to improve current therapies

Le but de cette thèse est d’investiguer l’organisation fonctionnelle du contrôle cognitif au sein du cortex préfrontal latéral dans la schizophrénie. Chez le sujet sain, Koechlin et coll. (Science, 2003) ont montré que le cortex préfrontal latéral était structuré en une cascade de processus de contrôle allant des régions antérieures aux régions postérieures, intégrant respectivement les informations épisodiques (événements antérieurs) et contextuelles (le contexte immédiat de l’action) au choix de l’action en réponse à un stimulus externe. En utilisant le paradigme expérimental de Koechlin et coll. en IRM fonctionnelle, nous avons investigué l’architecture fonctionnelle du contrôle cognitif au sein du cortex latéral préfrontal chez 15 patients schizophrènes et 14 sujets contrôles appariés. Dans une première étude, nous avons trouvé que les patients schizophrènes présentaient un déficit sélectif du contrôle contextuel associé à une hypoactivation des régions postérieures préfrontales, expliquant la désorganisation du discours et du comportement observés chez ces patients. Par ailleurs, les patients schizophrènes hyperactivaient leurs régions rostrales du cortex préfrontal latéral pendant le contrôle des informations de nature épisodique, ce que nous avons interprété comme une tentative de compensation infructueuse des dysfonctions du contrôle contextuel. Dans une seconde étude, nous avons montré que les patients schizophrènes présentaient également une perturbation du traitement top-down des informations de nature épisodique, liée à une dysconnectivité des régions rostrales vers les régions caudales du cortex préfrontal latéral. / The goal of this thesis is to investigate the functional organization of cognitive control within the LPFC in schizophrenia. We used a model postulating that cognitive control is functionally organized within the lateral prefrontal cortex (LPFC) as a cascade of representations ranging from premotor to anterior LPFC regions according to stimuli, the present perceptual context, and the temporal episode in which stimuli occur. Using functional magnetic resonance imaging, we investigated the functional architecture of cognitive control within the LPFC in 15 schizophrenic patients and 14 matched healthy controls. In a first study, we found that immediate contextual signals insufficiently bias the caudal LPFC activity required to select the appropriate behavioral representation. This specific deficit could thus alter the internal consistency of schizophrenic patients’ behavior. To compensate for this weakening of contextual influence, schizophrenic patients may inefficiently use temporal episodic information through higher activation in rostral LPFC regions. In a second study, we showed that schizophrenic patients inappropriately process episodic information flow along a rostro-caudal axis within the LPFC. This top-down episodic control dysfunction could lead to a disruption of episodic memory that could account for the patients’ difficulties in organizing their behavior across time. All the results argue in favor of both dysfunctional specialization and integration within the LPFC in schizophrenia.