Older adults compensate for switch, but not mixing costs, relative to younger adults on an intrinsically cued task switching experiment.

Introduction: Aging negatively impacts the ability to rapidly and successfully switch between two or more tasks that have different rules or objectives. However, previous work has shown that the context impacts the extent of this age-related impairment: while there is relative age-related invariance when participants must rapidly switch back and forth between two simple tasks (often called "switch costs"), age-related differences emerge when the contexts changes from one in which only one task must be performed to one in which multiple tasks must be performed, but a trial-level switch is not required (e.g., task repeat trials within dual task blocks, often called "mixing costs"). Here, we explored these two kinds of costs behaviorally, and also investigated the neural correlates of these effects. Methods: Seventy-one younger adults and 175 older adults completed a task-switching experiment while they underwent fMRI brain imaging. We investigated the impact of age on behavioral performance and neural activity considering two types of potential costs: switch costs (dual-task switch trials minus dual-task non-switch trials), and mixing costs (dual-task non-switch minus single-task trials). Results: We replicated previous behavioral findings, with greater age associated with mixing, but not switch costs. Neurally, we found age-related compensatory activations for switch costs in the dorsal lateral prefrontal cortex, pars opercularis, superior temporal gyrus, and the posterior and anterior cingulate, but age-related under recruitment for mixing costs in fronto-parietal areas including the supramarginal gyrus and pre and supplemental motor areas. Discussion: These results suggest an age-based dissociation between executive components that contribute to task switching.

Executive Functions and Improvement of Thinking: An Intervention Program to Enhance Deductive Reasoning Abilities.

Empirical and theoretical advances and application to society are moved at different speed. Application work is frequently developed later because it requires the integration of knowledge from different research areas. In the present paper, we integrate literature coming from diverse areas of research in order to design a deductive reasoning intervention, based on the involved executive functions. Executive functions include working memory (WM)'s online executive processes and other off-line functions such as task revising and planning. Deductive reasoning is a sequential thinking process driven by reasoners' meta-deductive knowledge and goals that requires the construction and manipulation of representations. We present a new theoretical view about the relationship between executive function and higher-level thinking, a critical analysis of the possibilities and limitations of cognitive training, and a metacognitive training procedure on executive functions to improve deductive reasoning. This procedure integrates direct instruction on deduction and meta-deductive concepts (consistency, necessity) and strategies (search for counterexamples and exhaustivity), together with the simultaneous training of WM and executive functions involved: Focus and switch attention, update WM representations, inhibit and revise intuitive responses, and control the emotional stress yielded by tasks. Likewise, it includes direct training of some complex WM tasks that demands people to carry out similar cognitive assignment than deduction. Our training program would be included in the school curriculum and attempts not only to improve deductive reasoning in experimental tasks, but also to increase students' ability to uncover fallacies in discourse, to automatize some basic logical skills, and to be able to use logical intuitions.

Cognitive flexibility and attentional patterns among trauma survivors: preliminary evidence from an eye-tracking study.

Background: Executive functioning has been linked to both the development of post-traumatic symptoms and the efficiency of therapy. Specifically, flexibility processes seem to play a major role in the use of efficient coping strategies after a traumatic event. However, only a few studies have focused on the links between flexibility, resilience, and concrete behaviours displayed by individuals. Objective: The aim of this study was to investigate the influence of emotional content on the efficiency of cognitive flexibility among trauma-exposed individuals. Method: Twenty-eight trauma-exposed (TE) and 27 non-trauma-exposed (NTE) individuals performed an overlap task in which neutral, positive, and negative pictures appeared in the centre of the screen. Participants were required to disengage their attentional focus from this picture to identify a peripheral target. Analyses included eye movements during the presentation of the scenes and the response times associated with target localization. Results: TE individuals initially presented a rapid overt disengagement from both neutral and negative emotional information. In other words, TE participants moved their gaze away from the central picture towards the target more rapidly than NTE participants. However, TE participants then displayed longer reaction times to identify the target in comparison with NTE participants. Discussion: This study presents preliminary evidence that cognitive flexibility may be relevant when considering the impact of trauma. The developed task could provide a novel way to assess this flexibility within an emotional context. HIGHLIGHTS: • This study developed an original assessment of cognitive flexibility processes in an emotional context.• Cognitive flexibility was assessed using an overlap task and eye-tracking technology.• Cognitive flexibility may be relevant when considering the impact of a trauma.

Antecedentes: El funcionamiento ejecutivo se ha relacionado tanto con el desarrollo de síntomas postraumáticos como con la eficiencia de la terapia. Específicamente, los procesos de flexibilidad parecen jugar un papel importante en el uso de estrategias de afrontamiento después de un evento traumático. Sin embargo, solo unos pocos estudios se han centrado en los vínculos entre la flexibilidad, la resiliencia y los comportamientos concretos que muestran los individuos.Objetivo: El objetivo de este estudio fue investigar la influencia del contenido emocional en la eficiencia de la flexibilidad cognitiva entre individuos expuestos a traumas.Método: 28 personas expuestas a trauma (ET) y 27 no expuestas a trauma (NET) realizaron una tarea superpuesta en la que aparecían imágenes neutras, positivas y negativas en el centro de la pantalla. Se pidió a los participantes que desvincularan su foco de atención de esta imagen para identificar un objetivo periférico. Los análisis incluyeron movimientos oculares durante la presentación de las escenas y los tiempos de respuesta asociados con la localización del objetivo.Resultados: Los individuos con ET inicialmente presentaron una desconexión abierta y rápida de la información emocional tanto neutral como negativa. En otras palabras, los participantes con ET alejaron su mirada de la imagen central hacia el objetivo más rápido que los participantes NET. Sin embargo, los participantes con ET mostraron tiempos de reacción más largos para identificar el objetivo en comparación con los participantes NET.Discusión: Los individuos con ET inicialmente presentaron una desconexión abierta y rápida de la información emocional tanto neutral como negativa. En otras palabras, los participantes con ET alejaron su mirada de la imagen central hacia el objetivo más rápido que los participantes NET. Sin embargo, los participantes con ET mostraron tiempos de reacción más largos para identificar el objetivo en comparación con los participantes NET.

Inhibitory control is associated with medication adherence in young HIV patients without comorbidities.

OBJECTIVE: In the present study we evaluated the incremental contribution of executive cognition (EC) subprocesses to antiretroviral medication adherence. METHOD: A comprehensive EC test battery assessing updating/working memory, mental flexibility, and inhibitory control, along with measures assessing non-executive cognitive functions were completed by 100 individuals with HIV. Medication adherence was determined via a visual analogue self-report scale and the Medication Adherence Questionnaire. Potential predictors, including demographic and clinical characteristics and neuropsychological performances on EC and other cognitive tasks were regressed to medication adherence. Predictive variables related to executive processes were added in the final block of the hierarchical regression model in order to assess their incremental predictive ability on medication adherence. RESULTS: 23% of the variance in the visual analogue scale was explained by treatment complexity, memory and EC performance. A measure of inhibitory control, in particular, predicted self-reported medication adherence above and beyond demographic, clinical and other cognitive factors. CONCLUSIONS: The contribution of EC to self-reported medication adherence in young seropositive adults was limited, but inhibitory control was associated with proper medication management above and beyond demographic, clinical and other cognitive functions.

Executive Functions and Improvement of Thinking: An Intervention Program to Enhance Deductive Reasoning Abilities

Empirical and theoretical advances and application to society are moved at different speed. Application work is frequently developed later because it requires the integration of knowledge from different research areas. In the present paper, we integrate literature coming from diverse areas of research in order to design a deductive reasoning intervention, based on the involved executive functions. Executive functions include working memory (WM)’s online executive processes and other off-line functions such as task revising and planning. Deductive reasoning is a sequential thinking process driven by reasoners’ meta-deductive knowledge and goals that requires the construction and manipulation of representations. We present a new theoretical view about the relationship between executive function and higher-level thinking, a critical analysis of the possibilities and limitations of cognitive training, and a metacognitive training procedure on executive functions to improve deductive reasoning. This procedure integrates direct instruction on deduction and meta-deductive concepts (consistency, necessity) and strategies (search for counterexamples and exhaustivity), together with the simultaneous training of WM and executive functions involved: Focus and switch attention, update WM representations, inhibit and revise intuitive responses, and control the emotional stress yielded by tasks. Likewise, it includes direct training of some complex WM tasks that demands people to carry out similar cognitive assignment than deduction. Our training program would be included in the school curriculum and attempts not only to improve deductive reasoning in experimental tasks, but also to increase students’ ability to uncover fallacies in discourse, to automatize some basic logical skills, and to be able to use logical intuitions. (AU)

Executive Processes and Emotional and Behavioural Problems in Youths Under Protective Measures.

This research studies the executive processes of youths under protective measures between 13 and 18years of age, as well as the emotional problems they have and the presence of behavioural problems, such as difficulties to control and direct attention, to control one's own behaviour and inhibit inadequate or ineffective responses (hyperactivity-impulsiveness) and problems related to emotional regulation. In addition, we study the presence of significant differences according to the sex of the youths. We also analyse to what extent the difficulties in the executive processes are related to and can predict the emotional and behavioural problems. The instruments used were Stroop's Colour and Word Test (Stroop), the Paths Test (TESen), and the System of Evaluation for Children and Adolescents (SENA). The results indicated that the youths had difficulties in such executive processes as execution, speed, and accuracy in carrying out tasks. Furthermore, they had emotion problems, amongst which the symptoms of anxiety are worthy of note; whilst attention deficit, hyperactivity-impulsiveness, and problems related to emotional regulation could also be observed. The data indicated greater difficulties in the executive processes for males than for females. There was a greater emotional symptomatology in the females, whilst there were greater deficits in attention and hyperactivity/impulsiveness in the males. Similarly, the deficits in the executive processes were related to and predicted emotional and behavioural problems. This research suggests the design of a structured programme focused on systematic training in real, daily situations, recommending the use of restorative techniques to work on the affected cognitive skills and techniques aimed at improving the youths' emotion regulation.

In Search of the Executive Cognitive Processes Proposed by Process-Overlap Theory.

Process-Overlap Theory (POT) suggests that measures of cognitive abilities sample from sets of independent cognitive processes. These cognitive processes can be separated into domain-general executive processes, sampled by the majority of cognitive ability measures, and domain-specific processes, sampled only by measures within a certain domain. According to POT, fluid intelligence measures are related because different tests sample similar domain-general executive cognitive processes to some extent. Re-analyzing data from a study by De Simoni and von Bastian (2018), we assessed domain-general variance from executive processing tasks measuring inhibition, shifting, and efficiency of removal from working memory, as well as examined their relation to a domain-general factor extracted from fluid intelligence measures. The results showed that domain-general factors reflecting general processing speed were moderately and negatively correlated with the domain-general fluid intelligence factor (r = -.17--.36). However, domain-general factors isolating variance specific to inhibition, shifting, and removal showed only small and inconsistent correlations with the domain-general fluid intelligence factor (r = .02--.22). These findings suggest that (1) executive processing tasks sample only few domain-general executive processes also sampled by fluid intelligence measures, as well as (2) that domain-general speed of processing contributes more strongly to individual differences in fluid intelligence than do domain-general executive processes.

Eye-tracking exploration of inhibitory control in post-traumatic stress disorder: an emotional antisaccade paradigm.

Background: Cognitive-behavioural studies among individuals suffering from post-traumatic stress disorder (PTSD) have highlighted attentional biases towards threats as a key factor in the maintenance of the disorder. Anxiety-related studies have hypothesized that attentional biases were due to attentional control difficulties in inhibition and flexibility of threatening information. Objective: Because it remains unclear how this theory could be applied to PTSD, this study aims to evaluate the inhibitory control and flexibility abilities of negative and threatening information in this population, using eye-tracking technology. Method: Fifteen adults with a history of physical assault and a current diagnosis of PTSD, and 15 healthy control participants, completed an original mixed antisaccade task. Results: We found enhanced overt attentional allocation towards every item of emotional information among PTSD participants, such as indexed by the latencies of the first saccade in prosaccade trials, followed by disengagement difficulties, such as indexed by increased reaction time to identify the target. Conclusion: Our results could represent empirical evidence of the general enhancement of attentional vigilance in people with PTSD in comparison with healthy controls, as well as specific inhibitory deficits. The results are interpreted through a fear-generalization hypothesis.

Antecedentes: Los estudios cognitivo-conductuales entre personas que padecen Trastorno de Estrés Postraumático (TEPT) han destacado los sesgos atencionales (AB, por su sigla en inglés) por amenaza como factor clave para el mantenimiento del trastorno. La literatura relacionada con ansiedad ha planteado la hipótesis de que los AB se debían a la dificultad del control atencional en la inhibición y flexibilidad de la información amenazante (Eysenck, 2008).Objetivo: Debido a que no está claro cómo se podría aplicar esta teoría al TEPT, este estudio tiene como objetivo evaluar el control inhibitorio y las capacidades de flexibilidad de la información negativa y amenazante en esta población, utilizando tecnología de seguimiento-ocular.Método: 15 adultos agredidos físicamente con un diagnóstico actual de TEPT y 15 participantes de Controles Sanos (CS) completaron una tarea original de antisacada mixta.Resultados: Encontramos una asignación atencional directa-abierta aumentada hacia información emocional entre los participantes con TEPT, tales como las latencias indexadas de la primera sacada en los ensayos de prosacada, seguida por las dificultades de desenganche, indexada por un tiempo de reacción mayor para identificar el objetivo diana.Conclusión: Nuestros resultados podrían representar una evidencia empírica de un aumento general de la vigilancia atencional en el TEPT en comparación con los CS, así como de déficits inhibitorios específicos. Los resultados se interpretan a través de una hipótesis de generalización del miedo.

How Executive Processes Explain the Overlap between Working Memory Capacity and Fluid Intelligence: A Test of Process Overlap Theory.

Working memory capacity (WMC) and fluid intelligence (Gf) are highly correlated, but what accounts for this relationship remains elusive. Process-overlap theory (POT) proposes that the positive manifold is mainly caused by the overlap of domain-general executive processes which are involved in a battery of mental tests. Thus, executive processes are proposed to explain the relationship between WMC and Gf. The current study aims to (1) achieve a relatively purified representation of the core executive processes including shifting and inhibition by a novel approach combining experimental manipulations and fixed-links modeling, and (2) to explore whether these executive processes account for the overlap between WMC and Gf. To these ends, we reanalyzed data of 215 university students who completed measures of WMC, Gf, and executive processes. Results showed that the model with a common factor, as well as shifting and inhibition factors, provided the best fit to the data of the executive function (EF) task. These components explained around 88% of the variance shared by WMC and Gf. However, it was the common EF factor, rather than inhibition and shifting, that played a major part in explaining the common variance. These results do not support POT as underlying the relationship between WMC and Gf.

Advancing the Personalization of Assessment and Intervention in Autistic Adolescents and Young Adults by Targeting Self-Determination and Executive Processes.

As autistic adolescents and young adults navigate the transition to adulthood, there is a need to partner with them to identify strengths and needed supports to enable goal-directed actions. This article conceptually integrates research on self-determination, defined by Causal Agency Theory, and executive processes in autism to provide direction for future research and practice. We describe how integrating research on self-determination and executive processes could enable autistic adolescents and young adults to be engaged in the process of assessing executive processes and self-determination. We discuss how this can better inform personalization of supports for self-determination interventions by focusing on support needs related to executive processes, including inhibitory control and cognitive flexibility, from a strengths-based perspective. We discuss how this can enable self-determination interventions that promote outcomes aligned with the values of the autistic community.

ADHD and hyperactivity: The influence of cognitive processing demands on gross motor activity level in children.

Excessive gross motor activity is a prominent feature of children with ADHD, and accruing evidence indicates that their gross motor activity is significantly higher in situations associated with high relative to low working memory processing demands. It remains unknown, however, whether children's gross motor activity rises to an absolute level or accelerates incrementally as a function of increasingly more difficult cognitive processing demands imposed on the limited capacity working memory (WM) system - a question of both theoretical and applied significance. The present investigation examined the activity level of 8- to 12-year-old children with ADHD (n = 36) and Typically Developing (TD) children (n = 24) during multiple experimental conditions: a control condition with no storage and negligible WM processing demands; a short-term memory (STM) storage condition; and a sequence of WM conditions that required both STM and incrementally more difficult higher-order cognitive processing. Relative to the control condition, all children, regardless of diagnostic status, exhibited higher levels of gross motor activity while engaged in WM tasks that required STM alone and STM combined with upper level cognitive processing demands, and children with ADHD were motorically more active under all WM conditions relative to TD children. The increase in activity as a consequence of cognitive demand was similar for all experimental conditions. Findings suggest that upregulation of physical movement rises and remains relatively stable to promote arousal related mechanisms when engaged in cognitive activities involving WM for all children, and to a greater extent for children with ADHD.

Age-related changes in the neural dynamics of bottom-up and top-down processing during visual object recognition: an electrophysiological investigation.

When recognizing objects in our environments, we rely on both what we see and what we know. While older adults often display increased sensitivity to top-down influences of contextual information during object recognition, the locus of this increased sensitivity remains unresolved. To examine the effects of aging on the neural dynamics of bottom-up and top-down visual processing during rapid object recognition, we probed the differential effects of object perceptual ambiguity and scene context congruity on specific EEG event-related potential components indexing dissociable processes along the visual processing stream. Older adults displayed larger behavioral scene congruity effects than young adults. Older adults' larger visual P2 amplitudes to object perceptual ambiguity (as opposed to the scene congruity P2 effects in young adults) suggest continued resolution of perceptual ambiguity that interfered with scene congruity processing, while post-perceptual semantic integration (as indexed by N400) remained largely intact. These findings suggest that compromised bottom-up perceptual processing in healthy aging leads to an increased involvement of top-down processes to resolve greater perceptual ambiguity during object recognition.

Enactment effect in patients with Alzheimer's disease.

Introduction: Subjects can improve their performance on memory for action phrases if, during the encoding condition, they self-perform actions associated with verbs (subject-performed condition), or if they perceive the actions carried out by experimenter (experimenter-performed condition), with respect to a verbal task condition in which they only read or listen to the stimuli. This facilitation is labeled "Enactment effect" (EE), and is thought to be associated with episodic integration processes binding actions and nouns together in a coherent representation. Only recently, studies addressed EE in AD individuals reporting significant improvements on memory tasks in the subject-performed encoding condition. However, no studies tried to explore the cognitive mechanisms supporting EE in AD individuals. Method: Performance on recognition and cued recall tasks for action phrases were assessed in a sample of 32 mild-to-moderate AD individuals and 30 healthy adults, in verbal, subject-performed and experimenter-performed encoding conditions. Moreover, a cognitive assessment was completed to explore the possible correlates of EE in our participants. Results: Results showed that both subject-performed and experimenter-performed encoding conditions produced similar advantages over the verbal condition, in both memory tasks in both groups. Moreover, these memory advantages were strongly associated to executive processes, in both AD and healthy adults. Conclusions: The present study confirmed that EE is spared in mild to moderate AD. Our findings supported the role of episodic integration processes and suggested a contribution of executive processes in EE.

Limited Benefit of Sleep Extension on Cognitive Deficits During Total Sleep Deprivation: Illustration With Two Executive Processes.

Introduction: Sleep extension has been associated with better alertness and sustained attention capacities before, during and after sleep loss. However, less is known about such beneficial effect on executive functions (EFs). Our aim was to investigate such effects on two EFs (i.e., inhibition and working memory) for subjects submitted to total sleep deprivation and one-night of recovery. Methods: Fourteen healthy men (26-37 years old) participated in an experimental cross-over design with two conditions: extended sleep (EXT, 9.8 ± 0.1 h of Time In Bed, TIB) and habitual sleep (HAB, 8.2 ± 0.1 h TIB). During these two conditions subjects underwent two consecutive phases: Six nights of either EXT or HAB followed by 3 days in-laboratory: baseline (BASE), TSD (38 h) and after recovery (REC). EFs capacities were assessed through Go-NoGo (inhibition) and 2N-Back (working memory) tasks. Both EFs capacities were measured at different time (BASE/TSD/REC: 09:30, 13:00, 16:00; TSD: 21:00, 00:00, 03:00, 06:30). Results: In both conditions (HAB and EXT), TSD was associated with deficits in inhibition (higher errors and mean reaction time from TSD 09:30 until the end; p < 0.05) and working memory (lower corrects responses from TSD 06:30 or 09:30; p < 0.05). We observed no significant differences between HAB and EXT conditions on EFs capacities during BASE, TSD, and REC periods. Conclusion: Six nights of sleep extension is neither efficient to reduce core EFs deficits related to TSD nor to improve such capacities after a recovery night. These results highlight that sleep extension (six nights of 10 h of TIB) is not effective to limit EFs deficits related to TSD suggesting a disconnection inside cognition between executive and sustained attention processes. Clinical Trials: NCT02352272.

A New Look to a Classic Issue: Reasoning and Academic Achievement at Secondary School.

Higher-order thinking abilities such as abstract reasoning and meaningful school learning occur sequentially. The fulfillment of these tasks demands that people activate and use all of their working memory resources in a controlled and supervised way. The aims of this work were: (a) to study the interplay between two new reasoning measures, one mathematical (Cognitive Reflection Test) and the other verbal (Deductive Reasoning Test), and a third classical visuo-spatial reasoning measure (Raven Progressive Matrices Test); and (b) to investigate the relationship between these measures and academic achievement. Fifty-one 4th grade secondary school students participated in the experiment and completed the three reasoning tests. Academic achievement measures were the final numerical scores in seven basic subjects. The results demonstrated that cognitive reflection, visual, and verbal reasoning are intimately related and predicts academic achievement. This work confirms that abstract reasoning constitutes the most important higher-order cognitive ability that underlies academic achievement. It also reveals the importance of dual processes, verbal deduction and metacognition in ordinary teaching and learning at school.

Chain free association, creativity, and the default mode network.

Research on creativity shows that creative thinking entails both executive (controlled) and associative (spontaneous) processes. Yet standard creativity tasks cannot reliably isolate these two types of cognitive processes, making it difficult to understand the relation between the two and the roles of their corresponding brain networks in creative cognition. In this study we used a behavioral and neuroimaging approach in an effort to establish chain free association (FA) tasks as a relevant method for directly investigating spontaneous associative thinking and its role in creative cognition. We further examined the relation between performance on such tasks and intelligence. Participants completed common creativity tasks and then underwent fMRI scanning while producing FA chains. Instructions to participants that emphasized the spontaneous nature of the task, coupled with proper control conditions that were balanced for difficulty, enabled us to uncover spontaneous (as opposed to controlled) processes. To examine whether behavioral measures that can be derived from FA chains (associative fluency, associative flexibility and semantic remoteness between associations) are indicative of unconstrained spontaneous associative processing and are related to different aspects of verbal creativity and intelligence, scores on these measures were correlated with scores on creativity tasks and on an intelligence task, and with brain activity. We found that: (1) the Default Mode Network (DMN), a network involved in self-generated and internally-directed thought, was more involved in chain FA than in other tasks expected to reflect more controlled forms of internally-directed thought, suggesting that the DMN involvement might be related to the unconstrained spontaneous nature of chain FA. Higher involvement of the left IFG, SFG, MFG under chain FA was also revealed; (2) higher scores on different behavioral measures from FA chains were related to higher activation of the DMN and to reduced activation of the left IFG, a major node in the executive function network; (3) behavioral measures from FA chains were correlated with different aspects of creative performance but not with intelligence. Taken together, these findings lend support to the hypothesis that chain FA involves associative spontaneous thinking. They further suggest that behavioral measures derived from chain FA could indicate patterns of unconstrained associative thinking, related to reduced cognitive control, that are relevant for creative ideation, and might be able to serve as a measure of these patterns.

Intentionally fabricated autobiographical memories.

Participants generated both autobiographical memories (AMs) that they believed to be true and intentionally fabricated autobiographical memories (IFAMs). Memories were constructed while a concurrent memory load (random 8-digit sequence) was held in mind or while there was no concurrent load. Amount and accuracy of recall of the concurrent memory load was reliably poorer following generation of IFAMs than following generation of AMs. There was no reliable effect of load on memory generation times; however, IFAMs always took longer to construct than AMs. Finally, replicating previous findings, fewer IFAMs had a field perspective than AMs, IFAMs were less vivid than AMs, and IFAMs contained more motion words (indicative of increased cognitive load). Taken together, these findings show a pattern of systematic differences that mark out IFAMs, and they also show that IFAMs can be identified indirectly by lowered performance on concurrent tasks that increase cognitive load.

Age-Related Shift in Neuro-Activation during a Word-Matching Task.

Growing evidence from the neuroscience of aging suggests that executive function plays a pivotal role in maintaining semantic processing performance. However, the presumed age-related activation changes that sustain executive semantic processing remain poorly understood. The aim of this study was to explore the executive aspects of semantic processing during a word-matching task with regard to age-related neuro-functional reorganization, as well as to identify factors that influence executive control profiles. Twenty younger and 20 older participants underwent fMRI scanning. The experimental task was based on word-matching, wherein visual feedback was used to instruct participants to either maintain or switch a semantic-matching rule. Response time and correct responses were assessed for each group. A battery of cognitive tests was administrated to all participants and the older group was divided into two subgroups based on their cognitive control profiles. Even though the percentage of correct responses was equivalent in the task performance between both groups and within the older groups, neuro-functional activation differed in frontoparietal regions with regards to age and cognitive control profiles. A correlation between behavioral measures (correct responses and response times) and brain signal changes was found in the left inferior parietal region in older participants. Results indicate that the shift in age-related activation from frontal to parietal regions can be viewed as another form of neuro-functional reorganization. The greater reliance on inferior parietal regions in the older compared to the younger group suggests that the executive control system is still efficient and sustains semantic processing in the healthy aging brain. Additionally, cognitive control profiles underlie executive ability differences in healthy aging appear to be associated with specific neuro-functional reorganization throughout frontal and parietal regions. These findings demonstrate that changes in neural support for executive semantic processing during a word-matching task are not only influenced by age, but also by cognitive control profile.

Differential Kinetics in Alteration and Recovery of Cognitive Processes from a Chronic Sleep Restriction in Young Healthy Men.

Chronic sleep restriction (CSR) induces neurobehavioral deficits in young and healthy people with a morning failure of sustained attention process. Testing both the kinetic of failure and recovery of different cognitive processes (i.e., attention, executive) under CSR and their potential links with subject's capacities (stay awake, baseline performance, age) and with some biological markers of stress and anabolism would be useful in order to understand the role of sleep debt on human behavior. Twelve healthy subjects spent 14 days in laboratory with 2 baseline days (B1 and B2, 8 h TIB) followed by 7 days of sleep restriction (SR1-SR7, 4 h TIB), 3 sleep recovery days (R1-R3, 8 h TIB) and two more ones 8 days later (R12-R13). Subjective sleepiness (KSS), maintenance of wakefulness latencies (MWT) were evaluated four times a day (10:00, 12:00 a.m. and 2:00, 4:00 p.m.) and cognitive tests were realized at morning (8:30 a.m.) and evening (6:30 p.m.) sessions during B2, SR1, SR4, SR7, R2, R3 and R13. Saliva (B2, SR7, R2, R13) and blood (B1, SR6, R1, R12) samples were collected in the morning. Cognitive processes were differently impaired and recovered with a more rapid kinetic for sustained attention process. Besides, a significant time of day effect was only evidenced for sustained attention failures that seemed to be related to subject's age and their morning capacity to stay awake. Executive processes were equally disturbed/recovered during the day and this failure/recovery process seemed to be mainly related to baseline subject's performance and to their capacity to stay awake. Morning concentrations of testosterone, cortisol and α-amylase were significantly decreased at SR6-SR7, but were either and respectively early (R1), tardily (after R2) and not at all (R13) recovered. All these results suggest a differential deleterious and restorative effect of CSR on cognition through biological changes of the stress pathway and subject's capacity (ClinicalTrials-NCT01989741).

Neural changes associated with semantic processing in healthy aging despite intact behavioral performance.

Semantic memory recruits an extensive neural network including the left inferior prefrontal cortex (IPC) and the left temporoparietal region, which are involved in semantic control processes, as well as the anterior temporal lobe region (ATL) which is considered to be involved in processing semantic information at a central level. However, little is known about the underlying neuronal integrity of the semantic network in normal aging. Young and older healthy adults carried out a semantic judgment task while their cortical activity was recorded using magnetoencephalography (MEG). Despite equivalent behavioral performance, young adults activated the left IPC to a greater extent than older adults, while the latter group recruited the temporoparietal region bilaterally and the left ATL to a greater extent than younger adults. Results indicate that significant neuronal changes occur in normal aging, mainly in regions underlying semantic control processes, despite an apparent stability in performance at the behavioral level.