On the evolutionary origins of executive functions

Ecological validity of executive function tests in predicting driving performance

Almost all of our everyday activities depend on executive function (EF) skills. In line with the increasing attention to the ecological validation of neuropsychological assessment and intervention methods, this study aimed to explore the ecological validity of a relevant set of widely used EF tests, mostly from well-known paradigms of EF assessment, in predicting driving ability. Ninety-six healthy novice drivers (Mage = 26.2 years, SD = 8.4; 48 female) completed four stages of our data collection including psychological, EF, and driving assessments. For the psychological assessment, validated measures of sensation-seeking, risk-taking, personality traits, ADHD symptoms, depression, anxiety, and stress were administered. For the EF assessment, selected tests from the Delis-Kaplan Executive Function System (D-KEFS: Trail Making, Design Fluency, and Tower) and the Behavioral Assessment of the Dysexecutive Syndrome (BADS: Key Search, Zoo Map, and Modified Six Elements) along with a computerized Stroop test were administered. For the driving assessment, we used a simulated driving test comprising of 14 key dimensions of driving skills. Several correlations and multiple regression analyses were conducted. Significant correlations were found between all the EF measures and driving performance. Moreover, the EF measures predicted the driving ability over and above the effects of previous driving experience and the psychological variables. These results provide supporting evidence for the ecological validity of the EF tests in predicting driving performance. The incorporation of assessment and intervention targeting multiple domains of EF into driving rehabilitation and education programs could be a focus of future research.

Components of hot and cold executive functions and their relations to different forms of stress resilience: A systematic review

Increasing evidence points out that Executive Functions (i.e., EFs) may be core mechanisms for the generation of resilient responses to adversity. A systematic review testing the relations between either affective (hot) and/or non-affective (cold) EFs (i.e., inhibition, flexibility and working memory updating) and resilience was conducted. A total of 449 articles were initially identified. After two steps of title-and-abstract (k = 449), and full-text reading filtering (k = 67), 11 studies were reviewed. Three studies included cold measures of working memory and supported significant positive relations between higher working memory functioning and higher trait resilience levels. One study included cold measures of inhibition and another one both hot and cold measures, with only the first one supporting a positive relation between more efficient inhibition and higher trait resilience levels. Finally, 7 studies measured flexibility in its cold and/or hot dimensions and overall supported significant relations between higher flexibility and higher levels of trait, process and outcome resilience measures. These results support the role of EFs performance to promote different forms of resilience. This review allows to identify different issues that need to be addressed in future research and highlight the need to integrate the analysis of all hot and cold EFs components to understand their role in the generation of resilience.

Predicting emotional consequences of disorganization among adults with neurodevelopmental disorders: a structural equation model

PURPOSE

Previous studies exhibited differences in sensory processing, motor coordination, metacognitive executive functions (EF-MI), and sleep quality among adults with neurodevelopmental disorders (NDD). This study aims to find relationships between those abilities and organization-in-time, focusing on emotional responses after decreased organization abilities.

MATERIALS AND METHODS

This is a secondary data analysis of a larger sample from three previous studies conducted in one laboratory. Data were collected from 290 adults; 149 with NDD and 141 sex- and age- (20-50 years) matched controls completed the Adolescent/Adult Sensory Profile, Adult Developmental Coordination Disorder, Adults Behavioral Rating Inventory of Executive Functions, Mini Sleep, and Time Organization and Participation questionnaires. Structural equation model (SEM) analysed relationships and variable prediction.

RESULTS

Significant between-group differences were found for all variables; SEM indicated similar paths in both groups. Sensory processing affected EF-MI and sleep quality and significantly correlated with motor coordination, affecting EF-MI; EF-MI affected organization-in-time. Sleep quality significantly affected organization-in-time, affecting emotional responses.

CONCLUSIONS

Sensory, motor, EF, and sleep differences were associated with decreased organization-in-time abilities of adults with NDD, adversely affecting their emotional well-being. Early detection of such differences and targeted interventions may improve daily functioning and life quality and prevent negative emotional implications.

Substantial parallel mediation contribution by cognitive domains in the relationship between adolescents' physical fitness and academic achievements: the Cogni-Action Project

Objective

To determine how cognitive domains mediate the link between fitness components, their global score (GFS), and adolescents' academic achievement (ACA) across various school subjects.

Methods

In this study, 1,296 adolescents aged 10-14 participated. GFS was computed by three fitness components (strength, muscular, and cardiorespiratory fitness) through the ALPHA-fitness test battery. ACA was determined by five school subjects (Language, English, Mathematics, Science, and History) and two academic scores (a) "Academic Average" (five subjects) and (b) "Academic-PISA" (Language, Mathematics, and Science). A principal component analysis was performed to establish four factors (working memory [WM], cognitive flexibility [CF], inhibitory control [IC], and fluid reasoning [FR]). A parallel mediation approach was implemented with 5,000 bootstrapped samples controlled for sex, maturity, central obesity, having breakfast before cognitive tasks, schools, and school vulnerability. Total, direct, indirect effects, and mediation percentages were estimated.

Results

Overall, the finding showed a full parallel mediation effect for Language (92.5%) and English (53.9%), while a partial mediation for Mathematics (43.0%), Science (43.8%), History (45.9%), "Academic Average" (50.6%), and "Academic-PISA" (51.5%). In particular, WM, IC, and FR mediated all school subjects except mathematics, where IC was not significant. CF has not mediated any relationship between GF and academic performance.

Conclusion

This study underscores the pivotal role of cognitive domains, specifically WM, IC, and FR, in mediating the link between physical fitness and academic performance in adolescents. These insights have relevant implications for educational and public health policies.

Functional social isolation mediates the association between depression and executive function in older women: findings from the Canadian Longitudinal Study on Aging Comprehensive cohort

Depression and social isolation increase risk for executive function declines and are among the top five modifiable risk factors for dementia. However, the interrelationships between depression, social isolation and executive function are not well established. Further evidence is needed to inform strategies to promote executive function and independence in older age. We examined whether social isolation mediated the association between depression and executive function in community-dwelling middle-aged and older adults and whether this association was modified by age and sex. Adults aged 45 to 85 years from the Canadian Longitudinal Study on Aging (CLSA) Comprehensive cohort were followed over three years (complete case analysis, n = 14,133). Baseline depressive symptoms, a history of clinical depression, and functional social isolation (perceived lack of social support) were self-reported. Executive function at follow-up was a composite measure of five cognitive tests. Conditional process analysis assessed the mediating effects of functional social isolation across age group and sex, adjusted for sociodemographic and health covariates. Functional social isolation significantly mediated the association of depressive symptoms (proportion mediated [PM] = 8.0%) or clinical depression (PM = 17.5%) with executive function only among women aged 75+ years. Functional social isolation explains a proportion of the total effect of depressive symptoms or clinical depression on executive function in women aged 75 and older. Although reverse causation cannot be ruled out, our findings suggest that interventions that reduce functional social isolation or depression in older women may promote executive function.

Principles for Adapting Assessments of Executive Function across Cultural Contexts

Direct assessments of executive functions (EFs) are increasingly used in research and clinical settings, with a central assumption that they assess "universal" underlying skills. Their use is spreading globally, raising questions about the cultural appropriateness of assessments devised in Western industrialized countries. We selectively reviewed multidisciplinary evidence and theory to identify sets of cultural preferences that may be at odds with the implicit assumptions of EF assessments. These preferences relate to motivation and compliance; cultural expectations for interpersonal engagement; contextualized vs. academic thinking; cultural notions of speed and time; the willingness to be silly, be incorrect, or do the opposite; and subject-matter familiarity. In each case, we discuss how the cultural preference may be incompatible with the assumptions of assessments, and how future research and practice can address the issue. Many of the cultural preferences discussed differ between interdependent and independent cultures and between schooled and unschooled populations. Adapting testing protocols to these cultural preferences in different contexts will be important for expanding our scientific understanding of EF from the narrow slice of the human population that has participated in the research to date.

The prefrontal cortex: from monkey to man

The prefrontal cortex is so important to human beings that, if deprived of it, our behaviour is reduced to action-reactions and automatisms, with no ability to make deliberate decisions. Why does the prefrontal cortex hold such importance in humans? In answer, this review draws on the proximity between humans and other primates, which enables us, through comparative anatomical-functional analysis, to understand the cognitive functions we have in common and specify those that distinguish humans from their closest cousins. First, a focus on the lateral region of the prefrontal cortex illustrates the existence of a continuum between rhesus monkeys (the most studied primates in neuroscience) and humans for most of the major cognitive functions in which this region of the brain plays a central role. This continuum involves the presence of elementary mental operations in the rhesus monkey (e.g. working memory or response inhibition) that are constitutive of 'macro-functions' such as planning, problem-solving and even language production. Second, the human prefrontal cortex has developed dramatically compared to that of other primates. This increase seems to concern the most anterior part (the frontopolar cortex). In humans, the development of the most anterior prefrontal cortex is associated with three major and interrelated cognitive changes: (i) a greater working memory capacity, allowing for greater integration of past experiences and prospective futures; (ii) a greater capacity to link discontinuous or distant data, whether temporal or semantic; and (iii) a greater capacity for abstraction, allowing humans to classify knowledge in different ways, to engage in analogical reasoning or to acquire abstract values that give rise to our beliefs and morals. Together, these new skills enable us, among other things, to develop highly sophisticated social interactions based on language, enabling us to conceive beliefs and moral judgements and to conceptualize, create and extend our vision of our environment beyond what we can physically grasp. Finally, a model of the transition of prefrontal functions between humans and non-human primates concludes this review.

Executive control of language in schizophrenia patients with history of auditory verbal hallucinations: A neuropsychological and resting-state fMRI study

BACKGROUND

As demonstrated by a plethora of studies, compromised executive functions (EF) and language are implicated in mechanisms of auditory verbal hallucinations (AVH), but the contribution of their interaction to AVH remains unclear. We hypothesized that schizophrenia patients with history of AVH (AVHh+) vs. without history of AVH (AVHh-) have a specific deficit of executive control of language and alterations in functional connectivity (FC) between the brain regions involved in EF and language, and these neuropsychological and neurophysiological traits are associated with each other.

METHODS

To explore the executive control of language and its contribution to AVH, we used an integrative approach involving analysis of neuropsychological and resting-state fMRI data of 34 AVHh+, 16 AVHh-, and 40 healthy controls. We identified the neuropsychological and FC measures that differentiated between AVHh+, AVHh-, and HC, and tested the associations between them.

RESULTS

AVHh+ were characterized by decreased category and phonological verbal fluency, utterance length, productivity in the planning tasks, and poorer retelling. AVHh+ had decreased FC between the left inferior frontal gyrus and the anterior cingulate cortex. Productivity in category verbal fluency was associated with the FC between these regions.

CONCLUSIONS

Poor executive control of word retrieval and deficient programming of sentence and narrative related to more general deficits of planning may be the neuropsychological traits specific for AVHh+. A neurophysiological trait specific for AVHh+ may be a decreased FC between regions involved in language production and differentiation between alien- vs. self-generated speech and between language production vs. comprehension.

Self-report versus performance based executive functioning in people with psychotic disorders

Background

Although executive functioning is often measured using performance-based measures, these measures have their limits, and self-report measures may provide added value. Especially since these two types of measures often do not correlate with one another. It thus has been proposed they might measure different aspects of the same construct. To explore the differences between a performance-based measure of executive functioning and a self-report measure, we examined their associations in patients with a psychotic disorder with the following: other neurocognitive measures; psychotic symptoms; anxiety and depression symptoms, and daily-life outcome measures.

Method

This cross-sectional study consisted of baseline measures collected as part of a cohort study of people with a psychotic disorder (the UP'S study; n = 301). The Behavioral Rating Inventory of Executive Functioning Adult version (BRIEF-A) was used to assess self-rated executive functioning, and the Tower of London (TOL) to assess performance-based executive functioning. Generalized linear models (GLM) were used with the appropriate distribution and link function to study the associations between TOL and BRIEF-A, and the other variables, including the Brief Assessment of Cognition in Schizophrenia (BACS), the Positive and Negative Symptoms Scale-Remission (PANSS-R), the General Anxiety Disorder - 7 (GAD-7), the Patient Health Questionnaire - 9 (PHQ-9) and the WHO Disability Assessment Schedule 2.0 (WHODAS 2.0). Model selection was based on the Wald test.

Results

The TOL was associated with other neurocognitive measures, such as verbal list learning (β = 0.24), digit sequencing (β = 0.35); token motor task (β = 0.20); verbal fluency (β = 0.24); symbol coding (β = 0.43); and a screener for intelligence (β = 2.02). It was not associated with PANNS-R or WHO-DAS scores. In contrast, the BRIEF-A was associated not with other neurocognitive measures, but with the PANSS-R (β = 0.32); PHQ-9 (β = 0.52); and GAD-7 (β = 0.55); and with all the WHODAS domains: cognition domain (β = 0.54), mobility domain (β = 0.30) and selfcare domain (β = 0.22).

Conclusion

Performance-based and self-report measures of executive functioning measure different aspects of executive functioning. Both have different associations with neurocognition, symptomatology and daily functioning measures. The difference between the two instruments is probably due to differences in the underlying construct assessed.

A cognitive rehabilitation program to improve hot and cool executive dysfunction in juvenile myoclonic epilepsy: Preliminary findings

OBJECTIVE

Executive and attentional deficits are often described in Juvenile Myoclonic Epilepsy (JME). We aimed to evaluate the short-term impact of rehabilitation developed for the most frequent cognitive deficits of persons with JME.

METHODS

Thirty-three patients entered this study which consisted of 12 individual sessions once a 60-minute week, divided into planning/organization, attention, and impulsivity. Twenty-seven patients finished the protocol, and all patients had pre-and-post evaluations from neuropsychological tests and self-rating questionnaires. Generalized Estimating Equations (GEE) inferential statistics were used to verify the protocol's effect, and a 95% confidence interval was adopted.

RESULTS

We found significant improvement in selective attention (TMT A [p < 0.01] and Stroop test 2 [p = 0.03]), inhibitory control (Stroop test 3 [p = 0.02], FAS [p < 0.01], CPT commissions [p < 0.01]), mental flexibility [WCST categories p < 0.01] and implicit decision making (IGT blocks A [p < 0.01], B [p = 0.02], C [p < 0.01] and D [p < 0.01]). All components of the Behavioral Rating Index of Executive Functions metacognition index and the general quotient had significant improvement (initiative [p ≤ 0.01], working memory [p ≤ 0.01], planning and organization [p ≤ 0.01], task monitor [p = 0.02] and organization of materials [p = 0.02]). Regarding the Behavioral Regulation Index, the "Emotional Control" was improved [p = 0.03]. The attentional component and general scores of the Adult Self-Report Scale for Adults also changed significantly [p ≤ 0.01].

SIGNIFICANCE

Executive function and attention had an improvement in objective and subjective tests. The context-dependent reactive mechanism of impulsivity improved in instruments based on the ecological evaluation. Our findings, though preliminary due to a lack of controls and practice effect corrections, support that cognitive rehabilitation may be a valuable resource to alleviate cognitive deficits in patients with JME.

Genetic Disruption of System xc-Mediated Glutamate Release from Astrocytes Increases Negative-Outcome Behaviors While Preserving Basic Brain Function in Rat

The importance of neuronal glutamate to synaptic transmission throughout the brain illustrates the immense therapeutic potential and safety risks of targeting this system. Astrocytes also release glutamate, the clinical relevance of which is unknown as the range of brain functions reliant on signaling from these cells hasn't been fully established. Here, we investigated system xc- (Sxc), which is a glutamate release mechanism with an in vivo rodent expression pattern that is restricted to astrocytes. As most animals do not express Sxc, we first compared the expression and sequence of the obligatory Sxc subunit xCT among major classes of vertebrate species. We found xCT to be ubiquitously expressed and under significant negative selective pressure. Hence, Sxc likely confers important advantages to vertebrate brain function that may promote biological fitness. Next, we assessed brain function in male genetically modified rats (MSxc) created to eliminate Sxc activity. Unlike other glutamatergic mechanisms, eliminating Sxc activity was not lethal and didn't alter growth patterns, telemetry measures of basic health, locomotor activity, or behaviors reliant on simple learning. However, MSxc rats exhibited deficits in tasks used to assess cognitive behavioral control. In a pavlovian conditioned approach, MSxc rats approached a food-predicted cue more frequently than WT rats, even when this response was punished. In attentional set shifting, MSxc rats displayed cognitive inflexibility because of an increased frequency of perseverative errors. MSxc rats also displayed heightened cocaine-primed drug seeking. Hence, a loss of Sxc-activity appears to weaken control over nonreinforced or negative-outcome behaviors without altering basic brain function.SIGNIFICANCE STATEMENT Glutamate is essential to synaptic activity throughout the brain, which illustrates immense therapeutic potential and risk. Notably, glutamatergic mechanisms are expressed by most types of brain cells. Hence, glutamate likely encodes multiple forms of intercellular signaling. Here, we hypothesized that the selective manipulation of astrocyte to neuron signaling would alter cognition without producing widespread brain impairments. First, we eliminated activity of the astrocytic glutamate release mechanism, Sxc, in rat. This impaired cognitive flexibility and increased expression of perseverative, maladaptive behaviors. Notably, eliminating Sxc activity did not alter metrics of health or noncognitive brain function. These data add to recent evidence that the brain expresses cognition-specific molecular mechanisms that could lead to highly precise, safe medications for impaired cognition.

Fronto-Cerebellar Neurometabolite Alterations After Methylphenidate in Children and Adolescents With ADHD: A Proton Magnetic Resonance Spectroscopy Study

OBJECTIVE

The fronto-cerebellar circuit is involved in ADHD pathophysiology. Methylphenidate, as a first-line medication for ADHD, affects different brain regions, however, its effect on the fronto-cerebellar circuit is not investigated sufficiently. We aimed to investigate the effect of 8-week treatment with methylphenidate on neurometabolite ratios in the fronto-cerebellar circuit in ADHD participants using magnetic resonance spectroscopy (MRS).

METHODS

Fifteen drug-naïve ADHD children and adolescents were enrolled in the present study. Two single-voxel MR spectra were acquired from the right dorsolateral prefrontal cortex (DLPFC) and left Crus 1, before and after the medication. Also, neuropsychological and behavioral assessments were administered.

RESULTS

After medication, the glutamate/creatine in the DLPFC and the choline/creatine in the Crus 1 decreased in the ADHD participants.

CONCLUSION

These findings propose that methylphenidate-induced metabolite changes in the fronto-cerebellar circuit could be associated with improvement in cognitive/behavioral characteristics in ADHD. Also, results highlighted cerebellar engagement in ADHD pathophysiology.

Multimodal multilayer network centrality relates to executive functioning

Executive functioning (EF) is a higher order cognitive process that is thought to depend on a network organization facilitating integration across subnetworks, in the context of which the central role of the fronto-parietal network (FPN) has been described across imaging and neurophysiological modalities. However, the potentially complementary unimodal information on the relevance of the FPN for EF has not yet been integrated. We employ a multilayer framework to allow for integration of different modalities into one 'network of networks.' We used diffusion MRI, resting-state functional MRI, MEG, and neuropsychological data obtained from 33 healthy adults to construct modality-specific single-layer networks as well as a single multilayer network per participant. We computed single-layer and multilayer eigenvector centrality of the FPN as a measure of integration in this network and examined their associations with EF. We found that higher multilayer FPN centrality, but not single-layer FPN centrality, was related to better EF. We did not find a statistically significant change in explained variance in EF when using the multilayer approach as compared to the single-layer measures. Overall, our results show the importance of FPN integration for EF and underline the promise of the multilayer framework toward better understanding cognitive functioning.

Transgender Youth Executive Functioning: Relationships with Anxiety Symptoms, Autism Spectrum Disorder, and Gender-Affirming Medical Treatment Status

Executive function (EF) underlies broad health and adaptive outcomes. For transgender youth, navigating gender discernment and gender affirmation demand EF. Yet, factors associated with transgender youth EF are unknown. We investigate hypothesized predictors of EF: over-represented conditions among transgender youth (anxiety and depression symptoms, autism spectrum disorder [ASD]) and gender-affirming care. One-hundred twenty-four transgender 11-21-year-olds participated. Parents/caregivers completed EF and mental health report measures. ASD diagnostics and gender-affirming medication histories were collected. 21 % of non-autistic and 69 % of autistic transgender youth had clinically elevated EF problems. Membership in the gender-affirming hormone treatment group was associated with better EF. ASD, anxiety symptoms, and membership in the long-duration pubertal suppression group were associated with poorer EF. Given the importance of EF skills for multiple outcomes, and the unique and additional EF demands specific to transgender youths' experiences, EF skill monitoring-and when appropriate, supports-should be considered for transgender youth.

Development of cool and hot executive function deficit in children born very low birth weight with normal early development: A longitudinal cohort from aged 6 to 10

BACKGROUND

Studies showed preterm children born with very low birth weight (VLBW, <1500 g) are at risk for poorer executive functions (EFs). However, very little research has been reported longitudinally on the development of both cool and hot EFs deficits in preschool to school-age VLBW preterm children with normal early development.

AIMS

Present study aimed to investigate the development of cool and hot EFs in VLWB preterm children longitudinally.

METHODS

Forty preterm children born VLBW were followed up at ages 6, 8, and 10. Fifty term-born controls were recruited at each age stage. Cool EFs was assessed using backward digit span subtest of WISC-IV, Knox's Cube Test, Comprehensive Non-verbal Attention Test Battery (CNAT), Tower of London (ToL), Wisconsin Card Sorting Test (WCST), and hot EFs was assessed using Theory of Mind (ToM) and Delay of Gratification (GIFT) tasks.

RESULTS

The six-year-old VLBW preterm group showed significantly lower scores of planning in ToL, inhibition control in CNAT, and in both ToM and GIFT tasks. There is no significant difference in average cool and hot EFs between the eight and ten-year-old preterm group and the control group.

CONCLUSIONS

At six, VLBW preterm infants with normal early development have delayed cool and hot EFs development. Although the average performance of EFs can reach the level of the control group with age increasing to eight and ten years, there are still individual differences. It is recommended that more complete development indicators be established in the future, and early intervention should be made for VLBW premature children with delayed EFs.

Self-management of daily life tasks in diploma-track youth with disabilities

PURPOSE

Youth with disabilities who graduate with a regular high school diploma often continue to have difficulties in their daily functioning that ultimately impact adulthood outcomes. To better understand these functional difficulties and determine how best to address them, it is important to distinguish deficits in discrete skills from difficulty organizing skills to self-manage complex tasks associated with adult roles. The purpose of this study was to explore the extent to which challenges in social, executive function and behavior management factors relate to these two aspects of daily functioning.

METHODS

This is a secondary analysis of the National Longitudinal Transition Study 2 funded by the United States Department of Education. The direct and indirect associations between youth underlying factors and self-management of daily life tasks (SMDLT) versus discrete functional skills were modelled using structural equation modelling.

RESULTS

A model incorporating social skills, communication, and behavior regulation explained 55% of the variance in SMDLT. In contrast, the model predicting discrete functional skills had fewer significant associations and described less variance (37%) in the outcome.

CONCLUSIONS

Findings suggest that using measures of SMDLT and designing targeted interventions for SMDLT might help improve participation in independent living and productivity for diploma-track youth with disabilities.Implications for rehabilitationSuccessful transition from high school to adult roles requires the ability to self-manage the daily life tasks required for those roles, such as employment, post-secondary education, and independent living.The ability to self-manage daily tasks is distinct from mastery of discrete functional skills and should be assessed with measures that uniquely examine this domain.Social and communication skills, executive functioning, and behavioral regulation, are important contributors to the ability to self-manage life tasks for diploma-track youth with disabilities and should be incorporated into multifaceted interventions.Interventions to improve self-management of tasks should include teaching strategies and practice coordinating underlying skills in flexible ways that meet the varying demands of tasks and diverse environments.

The Neglected Factor in the Relationship between Executive Functioning and Obesity: The Role of Motor Control

BACKGROUND

The association between obesity and executive functions (EFs) is highly controversial. It has been suggested that waist circumference (WC), compared to body mass index (BMI), is a better indicator of fat mass and EFs in obesity. Moreover, according to the viewpoint that the brain's functional architecture meets the need for interactive behavior, we hypothesize that the relationship between EFs and body weight might be mediated by the motor performance.

METHODS

General executive functioning (frontal assessment battery-15), additional cognitive subdomains (trail making test and digit span backward), and motor performance (finger tapping task) were assessed in a sample that included 330 volunteers (192 females, M age = 45.98 years, SD = 17.70, range = 18-86 years).

RESULTS

Hierarchical multiple regression analysis indicated that the FAB15 score and FTT negatively predicted WC but not BMI. A subsequent mediation analysis highlighted that the indirect effect of FAB15 on WC through finger tapping was statistically significant.

CONCLUSIONS

Our results suggest that WC, as compared to BMI, is a more effective measure for studying the association between EFs and body weight. Still, we found that the motor domain partially mediates the dynamics of such a relationship.

Cerebral Blood Flow Alterations and Obesity: A Systematic Review and Meta-Analysis

Background: Reduction in cerebral blood flow (CBF) plays an essential role in the cognitive impairment and dementia in obesity. However, current conclusions regarding CBF changes in patients with obesity are inconsistent. Objective: A systematic review and meta-analysis was performed to evaluate the relationship between obesity and CBF alterations. Methods: We systematically screened published cross-sectional and longitudinal studies focusing on the differences in CBF between obese and normal-weight individuals. Eighteen studies including 24,866 participants, of which seven articles reported longitudinal results, were evaluated in the present study. Results: The results of the meta-analysis showed that in cross-sectional studies, body mass index (BMI) was negatively associated with CBF (β= –0.31, 95% confidence interval [CI]: –0.44, –0.19). Moreover, this systematic review demonstrated that obese individuals showed global and regional reductions in the CBF and increased CBF in diverse functional areas of the frontal lobe, including the prefrontal cortex, left frontal superior orbital, right frontal mid-orbital cortex, and left premotor superior frontal gyrus. Conclusion: Our findings suggest that BMI, rather than waist circumference and waist-to-hip ratio, is inversely associated with CBF in cross-sectional studies. The CBF of obese individuals showed global and regional reductions, including the frontal lobe, temporal and parietal lobes, cerebellum, hippocampus, and thalamus.

Functional Relationship between Inhibitory Control, Cognitive Flexibility, Psychomotor Speed and Obesity

In the last decades, it has been proposed that executive functions may be particularly vulnerable to weight-related issues. However, evidence on the matter is mixed, especially when the effects of sociodemographic variables are weighted. Thus, the current study aimed at further examining the relationship between executive functions and obesity. To this aim, we compared treatment-seeking overweight, obese, and morbidly obese patients with normal-weight control participants. We examined general executive functioning (Frontal Assessment Battery−15) and different executive subdomains (e.g., inhibitory control, verbal fluency, and psychomotor speed) in a clinical sample including 208 outpatients with different degrees of BMI (52 overweight, BMI 25−30, M age = 34.38; 76 obese, BMI 30−40, M age = 38.00; 80 morbidly obese, BMI > 40, M age = 36.20). Ninety-six normal-weight subjects served as controls. No difference on executive scores was detected when obese patients were compared with over- or normal-weight subjects. Morbidly obese patients reported lower performance on executive scores than obese, overweight, and normal-weight subjects. Between-group difference emerged also when relevant covariates were taken into account. Our results support the view that morbid obesity is associated with lower executive performance, also considering the critical role exerted by sociodemographic (i.e., sex, age, and education) variables. Our results support the view that executive functioning should be accounted into the management of the obese patient because of non-negligible clinical relevance in diagnostic, therapeutic, and prognostic terms.

Cognitive impairment in the co-occurrence of alcohol dependence and major depression: neuropsychological assessment and event-related potentials analyses

To evaluate the putative detrimental effect of Major Depressive Disorder (MDD) on the cognitive impairment associated with Alcohol Dependence (AD), we contrasted the neuropsychological profile and behavioral responses of AD subjects, MDD individuals, and in those with a co-occurring AD-MDD diagnosis (DD). Patients and healthy subjects completed a comprehensive neuropsychological battery and were recorded for P200, P300, and N450 event-related potentials during memory and Stroop tasks. AD subjects exhibited a generalized detrimental neuropsychological performance; in contrast, in MDD individuals, impairment was limited to discrete domains. Notably, the deficits were distinctive in DD cases. A P200 increased amplitude in MDD, a decrease in P300 amplitude in AD, and increased latency of P300 in DD patients were the overt electrophysiological abnormalities identified. Dual patients also exhibited a distinct pattern of behavioral responses, particularly apparent during high-demand cognitive tasks. Specific ERP adjustments were associated with the short-term fluoxetine treatment in DD and MDD subjects; the SSRI also improved altered baseline performance in learning and cognitive flexibility in DD subjects. In conclusion, the neuropsychological and behavioral alterations detected in the co-occurrence of AD-MDD did not seem to be merely the sum of the negative contributions of the independent disorders.

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Dual diagnosis (DD) patients exhibited a distinctive pattern of cognitive impairments compared to single diagnosis subjects.

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The ERP alterations identified were not shared among affected groups.

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Dual patients exhibited idiosyncratic behavioral responses.

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Impaired executive functions in DD subjects improved with SSRI medication.

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Neuropsychological and behavioral alterations are not explained as the sum of negative contributions of individual diagnosis.

Executive Functions in Overweight and Obese Treatment-Seeking Patients: Cross-Sectional Data and Longitudinal Perspectives

BACKGROUND

Recent evidence suggests that a higher body weight may be linked to cognitive impairment in different domains involving executive/frontal functioning. However, challenging results are also available. Accordingly, our study was designed to verify whether (i) poor executive functions are related to a higher body weight and (ii) executive functioning could contribute to weight loss in treatment-seeking overweight and obese patients.

METHODS

We examined general executive functioning, inhibitory control, verbal fluency, and psychomotor speed in a sample including 104 overweight and obese patients. Forty-eight normal-weight subjects participated in the study as controls.

RESULTS

Univariate Analysis of Variance showed that obese patients obtained lower scores than overweight and normal-weight subjects in all executive measures, except for errors in the Stroop test. However, when sociodemographic variables entered the model as covariates, no between-group difference was detected. Furthermore, an adjusted multiple linear regression model highlighted no relationship between weight loss and executive scores at baseline.

CONCLUSIONS

Our results provide further evidence for the lack of association between obesity and the executive domains investigated. Conflicting findings from previous literature may likely be due to the unchecked confounding effects exerted by sociodemographic variables and inclusion/exclusion criteria.

Sex-specific cognitive effects of mild traumatic brain injury to the frontal and temporal lobes

BACKGROUND

Cognitive deficits are the most enduring and debilitating sequelae of mild traumatic brain injury (mTBI). However, relatively little is known about whether the cognitive effects of mTBI vary with respect to time post-injury, biological sex, and injury location.

OBJECTIVES

The aim of this study was to assess the effect of the side and site of mTBI and to determine whether these effects are sexually dimorphic.

METHODS

Male and female ICR mice were subjected to either a sham procedure or mTBI to the temporal lobes (right-sided or left-sided) or to the frontal lobes (bilateral) using a weight-drop model. After recovery, mice underwent a battery of behavioral tests at two post-injury time points.

RESULTS

Different mTBI impact locations produced dissociable patterns of memory deficits; the extent of these deficits varied across sexes, time points, and memory domains. In both sexes, frontal mTBI mice exhibited a delayed onset of spatial memory deficits. Additionally, the performance of the frontal and left temporal injured males and females was more variable than that of controls. Interestingly, only in females does the effect of mTBI on visual recognition memory depend on the time post-injury. Moreover, only in females does spatial recognition memory remain relatively intact after mTBI to the left temporal lobe.

CONCLUSION

This study showed that different mTBI impact sites produce dissociable and sex-specific patterns of cognitive deficits in mice. The results emphasize the importance of considering the injury site/side and biological sex when evaluating the cognitive sequelae of mTBI.

Higher general executive functions predicts lower body mass index by mitigating avoidance behaviors

BACKGROUND

The present study examines the relationship between obesity, executive functions, and body image in a nonclinical population from southern Italy.

METHODS

General executive functioning (Frontal Assessment Battery-15), and body image disturbances (Body Uneasiness Test) were assessed in a sample including 255 participants (138 females, M age = 43.51 years, SD = 17.94, range = 18-86 years; M body mass index (BMI) = 26.21, SD = 4.32, range = 18.03-38.79).

FINDINGS

Multiple Linear Regression Analysis indicated that age, years of education, FAB15 score, body image concerns, and avoidance predicted the variance of BMI. A subsequent mediation analysis highlighted that the indirect effect of FAB15 on BMI through avoidance was statistically significant.

INTERPRETATION

Our results suggest that more performing executive functioning predicts a decrease in BMI that is partially due to the mitigation of avoidance behaviors.

A meta-analysis of the executive function components inhibition, shifting, and attention in intellectual disabilities

BACKGROUND

Executive function is a concept for higher-order cognitive functions, which have the role of controller and modulator of cognitive abilities. The consensus in the literature is that people with an intellectual disability perform significantly lower on executive function tasks than groups matched on chronological age. The comparison with groups matched on mental age is less clear. Therefore, the objective of this meta-analysis was to investigate to what extent executive function is impaired in people with intellectual disability compared with a typically developing control group matched on mental age. It was also investigated if the executive function component and intellectual disability aetiology moderated the effect.

METHODS

Eligibility criteria were participants with intellectual disability (IQ ≤ 75) without a dual diagnosis; a comparison group matched on mental age; executive function outcome reported in a group comparison study design with n ≥ 10. Working memory tasks and ratings of executive function were not included. The literature search yielded 6637 potentially interesting articles. Twenty-six studies (with 99 effect sizes) including 1395 participants were included in the quantitative synthesis.

RESULTS

A multilevel random-effects meta-analysis found that people with intellectual disability performed statistically significantly lower than the mental age-matched group on the executive function tasks, g = -0.34, 95% confidence interval = [-0.53, -0.16]. However, the heterogeneity between effect sizes was large. The intellectual disability aetiology moderator was significant, but it only reduced the heterogeneity marginally.

CONCLUSION

The overall conclusion is that individuals with an intellectual disability have more problems with executive function tasks than mental age-matched controls. Limitations are the large unexplained variance and the remarkably high number (69) of different tests that were used, which make more detailed conclusions problematic. This meta-analysis implies that future studies need to be of better quality, to have higher power, and to a higher degree use the same executive function tests.

The Association Between Executive Functioning and Personal Recovery in People With Psychotic Disorders

Background

Recovery in psychotic disorder patients is a multidimensional concept that can include personal, symptomatic, societal, and functional recovery. Little is known about the associations between personal recovery (PR) and functional recovery (FR). FR involves a person's ability to recover or compensate for impaired cognition, such as executive functions, and the loss of skills.

Method

In this cross-sectional study (the UP'S study), we used measures of executive functioning and personal recovery to assess a cohort of people with a psychotic disorder. PR was measured using the Recovering Quality of Life (ReQOL) and Individual Recovery Outcomes (I.ROC). FR was assessed using two forms of assessment. The Behavioral Rating Inventory of Executive Functioning Adult version (BRIEF-A) was used for self-rated executive functioning, and the Tower of London (TOL) for performance-based executive functioning. Regression models were calculated between executive functioning (BRIEF-A and TOL) and PR (ReQOL and I.ROC). Model selection was based on the Wald test.

Results

The study included data on 260 participants. While total scores of BRIEF-A had a small negative association with those of the ReQOL (β = -0.28, P > .001) and the I.ROC (β = -0.41, P > .001), TOL scores were not significantly associated with the ReQOL scores (β = 0.03, P = .76) and the I.ROC scores (β = 0.17, P = 0.17).

Conclusion

Self-reported EF, which measures the accomplishment of goal pursuit in real life was associated with PR. However, processing efficiency and cognitive control as measured by performance-based EF were not.

Executive Functions and Deafness: Results in a Group of Cochlear Implanted Children

Objects: This study aimed to evaluate the Executive Function (EF) domains in a group of profoundly deaf children treated with cochlear implant (CI) in comparison to normal hearing (NH) children. The secondary aim was to evaluate the influence exerted by the age at cochlear implant activation on EFs. Materials and Methods: 32 children were enrolled into two groups: group A of 17 CI users with a mean age of 8.78 years and group B of 15 NH subjects with a mean age of 7.99 years (SD + 2.3). All subjects were tested using the following tests: the subtests for working memory of the neuropsychological evaluation battery for the developmental age (Batteria di valutazione neuropsicologica per l’età evolutive), inhibition and control of the impulsive response—CAF, and the tower of London test. Results: No children with CIs scored within the normal range in the tests administered for the evaluation of EF domains. The same scores were significantly lower when compared with scores obtained by NH children. Children with younger age at CI activation showed better executive performances in planning, working memory (backward digit span), and cognitive flexibility (categorical fluency). Conclusion: The results of this study highlight that cochlear implantation plays a role in improving hearing and consequently influences the development of EFs in deaf children.

A Short Version of the EFECO Online Questionnaire for the Assessment of Executive Functions in School-Age Children

Executive function (EF) is a group of processes that allow individuals to be goal-oriented and to have adaptive functioning, so that adequate performance is essential for success in activities of daily living, at school and in other activities. The present study aims to create a short version of the Executive Functioning Questionnaire (EFECO) since there is a gap in the Spanish literature due to the lack of behavioural observation questionnaires at school age. A total of 3926 participants completed the online questionnaire. Subsequently, the validity and reliability of the data are analysed. The results show that the short version of the questionnaire, the EFECO-S, has a structure with five dimensions (emotional self-control, initiation, working memory, inhibition, and spatial organisation), as well as a second-order factor (global executive skill) and high reliability (ordinal Alpha = 0.68-0.88). The EFECO is composed of 67 items, while the EFECO-S has 20 items, four per factor, which turns it into a quick and easy to apply test. Therefore, it becomes an interesting alternative to be applied in screening processes with children who may be experiencing executive difficulties.

Experiences of emotional and psychosocial functioning after frontal lobe resection for epilepsy

PURPOSE

Frontal lobe resection (FLR) is the second most common epilepsy surgery procedure in adults. Few studies address neuropsychological consequences after FLR. The aim of this study was to explore patients' and relatives' experiences of cognitive, emotional and social cognitive functioning after frontal lobe epilepsy surgery.

METHODS

Semi-structured interviews were held with 14 patients having gone through FLR as adults during the years 2000-2016 and 12 of their relatives. Interviews were audio-recorded, transcribed and analyzed with inductive qualitative content analysis.

RESULTS

Positive as well as negative consequences were described both by patients and relatives. Feelings of relief and an increased capacity to experience emotions of well-being were mainly experienced as related to seizure freedom. A newfound autonomy and a more grown-up identity as opposed to a self-image based on epilepsy was also highlighted. However, results also showed that even for seizure free patients, FLR could give rise to negative experiences, the most prominent of which were mental fatigue, lowered mood and social withdrawal. Coping strategies included planning ahead to avoid mental exhaustion. Over all, respondents considered that the epilepsy surgery had been a risk well worth taking and that positive consequences outweighed the negative ones.

CONCLUSIONS

This study shows a range of positive as well as negative outcomes after FLR for epilepsy. The findings indicate that lowered mood and mental fatigue could affect the life situation in a negative way, regardless of seizure outcome. This is important to consider in the preoperative counselling of patients and their families, as well as in the postsurgical follow-up. It is also crucial that the epilepsy surgery team has the possibility to offer rehabilitation and support to families regarding these aspects after surgery.

Loneliness-based impaired reward system pathway: Theoretical and clinical analysis and application

Loneliness is a key determinant in the etiology of mental health disorders such as depression and has profound impacts on health, quality of life, and economic productivity. This narrative review uses extant neurobiology and evolutionary literature to propose a construct through which loneliness may induce depression in adulthood via the reward system (including symptom and treatment aspects). Early childhood (distal) factors were found to be important in influencing adult (proximal) factors, which lead to the formulation of the construct. Due to the heterogenous and comorbid nature of depression, a new subtype known as 'reward depression' was distinguished along with distinct symptoms to aid practitioners when assessing patient treatment options. Furthermore, an evolutionary perspective was applied to the current impaired reward construct to discuss how the ancestral purpose and environment (in terms of reward) clashes with the modern one. Finally, theoretical treatment and prevention ideas were examined and discussed, leading into future work that needs to build upon and confirm the outlined construct.

Widespread white matter aberration is associated with the severity of apathy in amnestic Mild Cognitive Impairment: Tract-based spatial statistics analysis

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In aMCI, apathy severity was associated with lower FA in widespread WM pathways.

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WM aberrations are related to apathy severity after controlling for depression.

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Disruptions related to apathy severity are not limited to frontal-subcortical area.

Apathy is recognized as a prevalent behavioral symptom of amnestic Mild Cognitive Impairment (aMCI). In aMCI, apathy is associated with an increased risk and increases the risk of progression to Alzheimer’s Disease (AD). Previous DTI study in aMCI showed that apathy has been associated with white matter alterations in the cingulum, middle and inferior longitudinal fasciculus, fornix, and uncinate fasciculus. However, the underlying white matter correlates associated with apathy in aMCI are still unclear. We investigated this relationship using whole-brain diffusion tensor imaging (DTI). Twenty-nine aMCI patients and 20 matched cognitively healthy controls were included. Apathy severity was assessed using the Apathy Evaluation Scale Clinician version. We applied the tract-based spatial statistics analyses to DTI parameters: fractional anisotropy (FA), mean diffusivity, axial diffusivity, and radial diffusivity to investigate changes in white matter pathways associated with the severity of apathy. No significant difference was found in any of the DTI parameters between aMCI and the control group. In aMCI, higher severity of apathy was associated with lower FA in various white matter pathways including the left anterior part of inferior fronto-occipital fasciculus/uncinate fasciculus, genu and body of the corpus callosum, superior and anterior corona radiata, anterior thalamic radiation of both hemispheres and in the right superior longitudinal fasciculus/anterior segment of arcuate fasciculus (p < .05, TFCE-corrected) after controlling for age, gender and GDS non-apathy. A trend association was observed in the right posterior corona radiata and corticospinal tract/internal capsule, and bilateral forceps minor (p < .065, TFCE-corrected). In conclusion, in aMCI, severity of apathy is associated with aberrant white matter integrity in widely distributed pathways, within and between hemispheres.

Emotion recognition in nonhuman primates: How experimental research can contribute to a better understanding of underlying mechanisms

Recognising conspecifics' emotional expressions is important for nonhuman primates to navigate their physical and social environment. We address two possible mechanisms underlying emotion recognition: emotional contagion, the automatic matching of the observer's emotions to the emotional state of the observed individual, and cognitive empathy, the ability to understand the meaning and cause of emotional expressions while maintaining a distinction between own and others' emotions. We review experimental research in nonhuman primates to gain insight into the evolution of emotion recognition. Importantly, we focus on how emotional contagion and cognitive empathy can be studied experimentally. Evidence for aspects of cognitive empathy in different nonhuman primate lineages suggests that a wider range of primates than commonly assumed can infer emotional meaning from emotional expressions. Possibly, analogous rather than homologous evolution underlies emotion recognition. However, conclusions regarding its exact evolutionary course require more research in different modalities and species.

Relationships between childhood maltreatment, impairment in executive functions and disruptive behavior disorders in a community sample of children

Evidence points to an independent relationship among childhood maltreatment, impairments in executive functions (EF) and disruptive behavior disorders (DBD). However, it is still not fully understood how these three factors are interrelated. This study evaluated the association between childhood maltreatment and DBD testing the role of EF performance as a mediator or moderator. We studied a probabilistic school-based sample of 2016 children from 6 to 12 years. Mental disorders were assessed using the Development and Well-Being Assessment with parents and children. Children answered questions about exposure to child maltreatment and were evaluated with a set of cognitive tasks addressing inhibitory control, working memory, cognitive flexibility and planning. Childhood maltreatment was strongly associated with DBD (OR = 7.7, CI 95% 4.5-12.9). No association was found between childhood maltreatment and EF performance. Children with DBD showed worse performance in cognitive flexibility, which was not identified as a mediator or moderator of the association between childhood maltreatment and DBD. Results indicate that the association between maltreatment and disruptive behavior occurs regardless of performance in executive function in a community sample. Future studies are essential to confirm these findings and elucidate the cognitive mechanisms involved in this association.

Decision-making profile in older adults: the influence of cognitive impairment, premorbid intelligence and depressive symptoms

OBJECTIVE

Decision-making (DM) is a component of executive functioning. DM is essential to make proper decisions regarding important life and health issues. DM can be impaired in cognitive disorders among older adults, but current literature is scarce. The aim of this study was to evaluate the DM profile in participants with and without cognitive impairment.

DESIGN

Cross-sectional analysis of a cohort study on cognitive aging.

PARTICIPANTS

143 older adults.

SETTING

University-based memory clinic.

METHODS

Patients comprised three groups after inclusion and exclusion criteria: healthy controls (n=29), mild cognitive impairment (n=81) and dementia (n=33). Participants were evaluated using an extensive neuropsychological protocol. DM profile was evaluated by the Melbourne Decision Making Questionnaire. Multinomial logistic regression was used to evaluate associations between age, sex, educational level, estimated intelligence quotient (IQ), cognitive disorders, depressive or anxiety symptoms, and the DM profiles.

RESULTS

The most prevalent DM profile was the vigilant type, having a prevalence of 64.3%. The vigilant profile also predominated in all three groups. The multinomial logistic regression showed that the avoidance profile (i.e. buck-passing) was associated with a greater presence of dementia (p=0.046) and depressive symptoms (p=0.024), but with less anxious symptoms (p=0.047). The procrastination profile was also associated with depressive symptoms (p=0.048). Finally, the hypervigilant profile was associated with a lower pre-morbid IQ (p=0.007).

CONCLUSION

Older adults with cognitive impairment tended to make more unfavorable choices and have a more dysfunctional DM profile compared to healthy elders.

Effects of short-term mindfulness-based training on executive function: Divergent but promising

Mindfulness-based training (MBT) has repeatedly been proven effective in improving mental health, as well as in eliciting advantages in executive functions (EFs), as demonstrated by objective measures. However, few studies have discussed the role MBT plays in increasing EFs over short periods of time. This current review, to our knowledge, is the first study to investigate the effect of short-term MBT on EFs. In this case, 14 studies were eventually included after literature screening using PubMed, MEDLINE, Elsevier, Embase, EBSCO and references from retrieved articles. We found that the relationship between short-term MBT and three main components of EFs were found controversial. Some reported that individuals' inhibition, working memory and attention shifting were significantly improved by short-term MBT, whereas others reported no such strong connections between MBT and EFs. These controversial findings result from the use of varied assessment instruments, cognitive tasks and experimental materials. Nonetheless, the findings from this review suggest short-term MBT could be of great value in improving mental health, which might especially enable the enhancement of individuals' inhibition and updating subfunctions of EFs. These practical evidences could have a strong impact on clinical psychology. However, the lack of consistency across the studies in this review indicated that more standardized and profound studies exploring the effects of short-term MBT on EFs are needed in the future.

Cognitive predictors of self-awareness in patients with acquired brain injury along neuropsychological rehabilitation

Previous research has identified a critical role of executive function and memory in self-awareness, a metacognitive capacity often impaired in acquired brain injury. Through this observational study, we aimed to explore the effect of cognitive rehabilitation on the predictive value of these variables, as also whether any of them can predict the level of self-awareness once the cognitive rehabilitation is completed. 69 patients underwent a neuropsychological assessment, including self-awareness, at admission to and discharge from a cognitive rehabilitation process. Regression analysis was performed at these two moments and a third one was conducted to evaluate whether any of the variables at admission predicted the level of self-awareness at discharge. Verbal fluency was found to be the best predictor of self-awareness, both at admission and discharge. In addition, inhibition and cognitive flexibility, as well as episodic memory, appeared as significant predictors of post-rehabilitation self-awareness. Finally, verbal fluency was revealed as the unique pre-rehabilitation predictor of subsequent level of self-awareness following rehabilitation. While post-acute self-awareness is predicted by non-specific executive measures, the cognitive improvement putatively induced by neuropsychological rehabilitation reveals the contribution of more specific executive and memory functions. Importantly, pre-rehabilitation verbal fluency scores predicted the level of self-awareness after cognitive rehabilitation.

Theory of mind in Parkinson's disease: evidences in drug-naïve patients and longitudinal effects of dopaminergic therapy

Theory of mind (ToM) is the ability to attribute mental states to one self and others and to understand that others have beliefs different from one's own. Different subcomponents of ToM have also been identified: cognitive and affective. Cognitive ToM refers to the capacity to infer others' beliefs and intentions, while affective ToM implies the ability to appreciate others' emotional states. The aim of this study was to explore ToM in drug-naïve Parkinson's disease (PD) patients and to investigate the effects of chronic dopaminergic therapy on different subcomponents of ToM during a 3 months and 1 year of follow-up. We examined 16 PD patients in three conditions: before (un-medicated) and after dopaminergic therapy (medicated 3 months: T1 and medicated 1 year: T2). We also compared our PD's ToM abilities with 11 healthy individuals. ToM was explored with 5 different tasks: Faux Pas Test, Picture Sequencing Task Capture Story, Emotion Attribution Task, Strange Stories Task, and Karolinska Directed Emotional Faces. Our study confirms that PD patients present deficits in cognitive components of ToM and preserved performances in the affective ones in early stages of disease. We also find a significant effect of dopaminergic therapy on ToM already after 3 months with a good persistency after 1 year of treatment.

Cognitive abilities and life experience in everyday planning in adolescents with intellectual disabilities: Support for the difference model

BACKGROUND

The literature on planning ability in individuals with intellectual disability (ID) provides no clarity on whether their ability matches their mental age (MA) or not. Perhaps can planning experience explain the mixed results. The current study investigated to what extent cognitive abilities and life experience can explain everyday planning ability in individuals with ID and to what extent results from everyday planning tasks support the developmental or the difference model of ID.

METHOD

Planning tests, cognitive ability tasks and a self-rated life experience form were administered to 71 adolescents with ID and 62 children with a typical development matched on MA.

RESULTS

Adolescents with ID exhibited planning ability according to their MA. Regression analyses showed that the predictors of planning differed between the groups. The cognitive measures could predict planning in both groups, but life experience only contributed positively to planning in the MA group, whereas chronological age was negatively correlated with successful planning in the ID group.

CONCLUSIONS AND DISCUSSION

The results support the difference model of ID. When matched on MA, the individuals with ID will solve the planning task in a qualitatively different manner. Additionally, the participants with ID could not utilise their life experience when solving the planning task, contrary to the MA group. Practitioners should be aware that individuals with ID might need more everyday planning training throughout adolescence. To support adolescents with ID, practitioners may focus on supporting the individual's cognitive abilities rather than relying on their prior knowledge.

Measuring response inhibition with a continuous inhibitory-control task

Inhibitory control enables subjects to quickly react to unexpected changes in external demands. In humans, this kind of behavioral flexibility is often used as an indicator of an individual's executive functions, and more and more research has emerged to investigate this link in nonhuman animals as well. Here we explored the value of a recently developed continuous inhibitory-control task in assessing inhibitory-control capacities in animals. Pigeons completed a response-inhibition task that required them to adjust their movement in space in pursuit of a reward across changing target locations. Inhibition was measured in terms of movement trajectory (path taken toward the correct location for trials in which the target location did and did not change) and velocity (both before and after correcting the trajectory toward the changed location). Although the observed velocities did not follow any of our predictions in a clear way, the pigeons' movement trajectories did prove to be a good indicator of inhibitory control, showing that pigeons, though limited in their capacities relative to the sophisticated control strategies expressed by humans, are capable of exerting some forms of inhibitory control. These results strengthen the role of this paradigm as a valuable tool for evaluating inhibitory-control abilities across the animal kingdom.

Male and female cichlid fish show cognitive inhibitory control ability

Inhibitory control is a way to infer cognitive flexibility in animals by inhibiting a behavioral propensity to obtain a reward. Here we tested whether there are differences in inhibitory control between females and males of the fish Nile tilapia owing to their distinct reproductive roles. Individuals were tested under a detour-reaching paradigm, consisting of training fish to feed behind an opaque barrier and, thereafter, testing them with a transparent one. Fish is expected to avoid trying to cross through the transparent barrier to achieve food (reward), thus showing inhibitory control by recovering the learned detour with the opaque apparatus. Both males and females learned to detour the transparent barrier with similar scores of correct responses, whereas females reached the food faster. This result is probably associated to their different sex roles in reproduction: females care for the eggs and fry inside their mouth (thus requiring a high inhibitory control not to swallow them), whereas males have to stay inside the territory defending it against intruder males, which also demands some inhibitory ability not to leave the spawning site and take the risk of losing it. Furthermore, this evidence of cognitive flexibility can enable social fish to deal with unpredictable interactions.

Dissociation among preserved resistance to proactive interference and impaired behavioral inhibition in a patient with bilateral lesions in the inferior frontal gyrus: A single-case study

Inhibition is not a unitary construct, as different inhibition-related functions have been disentangled. The present single-case study compares performance of a patient with bilateral lesions in the inferior frontal gyrus (IFG) and anterior insula to healthy age-matched controls in different inhibition-related tasks. Particular focus was on the resolution of proactive interference that is supposed to rely on bilateral IFG and anterior insula. Two working memory tasks previously proven sensitive to deficits in proactive interference (recent-probes, n-back) and two tasks measuring behavioral inhibition (verb generation task, Stroop task) were administered. Against expectations, the patient did not show any deficits in measures of proactive interference. However, compared to controls, she demonstrated considerably reduced performance in both measures of behavioral inhibition, thus resulting in a classical dissociation between proactive interference and behavioral inhibition. Although performance improved during the chronic phase post stroke, the overall pattern of a classical dissociation between proactive interference and behavioral inhibition remained stable across time. Taken together, the present data support the role of the IFG in inhibition-related functions, but a direct relationship between lesions in the IFG and difficulties in resolution of proactive interference could not be corroborated.

Is diffuse axonal injury on susceptibility weighted imaging a biomarker for executive functioning in adolescents with traumatic brain injury?

Traumatic brain injury (TBI) is a heterogeneous disorder in which diffuse axonal injury (DAI) is an important component contributing to executive dysfunction. During adolescence, developing brain networks are especially vulnerable to acceleration-deceleration forces. We aimed to examine the correlation between DAI (number and localization) and executive functioning in adolescents with TBI. We recruited 18 adolescents with a mean age of 15y8m (SD = 1y7m), averaging 2.5 years after sustaining a moderate-to-severe TBI with documented DAI. Susceptibility Weighted Imaging sequence was administered to localize the DAI lesions. The adolescents performed a neurocognitive test-battery, addressing different aspects of executive functioning (working memory, attention, processing speed, planning ability) and their parents completed the Behavior Rating Inventory of Executive Function (BRIEF) - questionnaire. Executive performance of the TBI-group was compared with an age and gender matched control group of typically developing peers. Based on these results we focused on the Stockings of Cambridge test and the BRIEF to correlate with the total number and location of DAI. Results revealed that the anatomical distribution of DAI, especially in the corpus callosum and the deep brain nuclei, may have more implications for executive functioning than the total amount of DAI in adolescents. Results of this study may help guide targeted rehabilitation to redirect the disturbed development of executive function in adolescents with TBI.

He said, she said: Autism spectrum diagnosis and gender differentially affect relationships between executive functions and social communication

Autism spectrum disorder is characterized by difficulties with social communication, with a preponderance in males. Evidence supports a relationship between metacognitive executive functions (e.g. planning, working memory) and social communication in autism spectrum disorder, yet relationships with specific metacognitive executive functions and how gender alters the expression of these relationships require further study. We used multiple regression to examine relationships between informant-based measures of metacognitive executive function and social communication in intellectually able (IQ ⩾ 85) female ( n = 111; mean age = 10.2 ± 2.8; 31 autism spectrum disorder) and male youth ( n = 310; mean age = 10.5 ± 1.9; 146 autism spectrum disorder) with and without autism spectrum disorder from the Autism Brain Imaging Data Exchange-II database. Executive function–social communication relationships were different in females and males with autism spectrum disorder. Relationships between the entire metacognitive index and social communication were stronger in males with autism spectrum disorder than without; this pattern was also observed for metacognitive sub-indices ‘monitor’ and ‘working memory’. These patterns were not observed in females. Relationships between executive function and social communication appear different for female and male youth with an autism spectrum disorder diagnosis. To better understand the nature of metacognitive contributions to social communication in autism spectrum disorder, future work should investigate the co-development of monitoring, working memory and social communication, while taking gender into account.

Nicotinic Acetylcholine Receptor Ligands, Cognitive Function, and Preclinical Approaches to Drug Discovery

Interest in nicotinic acetylcholine receptor (nAChR) ligands as potential therapeutic agents for cognitive disorders began more than 30 years ago when it was first demonstrated that the tobacco alkaloid nicotine could improve cognitive function in nicotine-deprived smokers as well as nonsmokers. Numerous animal and human studies now indicate that nicotine and a variety of nAChR ligands have the potential to improve multiple domains of cognition including attention, spatial learning, working memory, recognition memory, and executive function. The purpose of this review is to (1) discuss several pharmacologic strategies that have been developed to enhance nAChR activity (eg, agonist, partial agonist, and positive allosteric modulator) and improve cognitive function, (2) provide a brief overview of some of the more common rodent behavioral tasks with established translational validity that have been used to evaluate nAChR ligands for effects on cognitive function, and (3) briefly discuss some of the topics of debate regarding the development of optimal therapeutic strategies using nAChR ligands. Because of their densities in the mammalian brain and the amount of literature available, the review primarily focuses on ligands of the high-affinity α4β2* nAChR ("*" indicates the possible presence of additional subunits in the complex) and the low-affinity α7 nAChR. The behavioral task discussion focuses on representative methods that have been designed to model specific domains of cognition that are relevant to human neuropsychiatric disorders and often evaluated in human clinical trials.

IMPLICATIONS

The preclinical literature continues to grow in support of the development of nAChR ligands for a variety of illnesses that affect humans. However, to date, no new nAChR ligand has been approved for any condition other than nicotine dependence. As discussed in this review, the studies conducted to date provide the impetus for continuing efforts to develop new nAChR strategies (ie, beyond simple agonist and partial agonist approaches) as well as to refine current behavioral strategies and create new animal models to address translational gaps in the drug discovery process.

The impact of indoor air temperature on the executive functions of human brain and the physiological responses of body

Background: This study aimed to investigate the effect size (ES) of air temperature on the executive functions of human brain and body physiological responses. Methods: In this empirical study, the participants included 35 male students who were exposed to 4 air temperature conditions of 18°C, 22°C, 26°C and 30°C in 4 separate sessions in an air conditioning chamber. The participants were simultaneously asked to take part in the N-back test. The accuracy, electrocardiogram (ECG) signals and the respiration rate were recorded to determine the effect of air temperature. Results: Compared to moderate air temperatures (22°C), high (30°C) and low (18°C) air temperatures had a much more profound effect on changes in heart beat rate, the accuracy of brain executive functions and the response time to stimuli. There were statistically significant differences in the accuracy by different workload levels and various air temperature conditions(P<0.05). Although the heart beat rate index, the ratio between low frequency and high frequency (LF/HF), and the respiratory rate were more profoundly affected by the higher and lower air temperatures than moderate air temperatures (P<0.05), this effect was not statistically significant, which may be due to significant reduction in the standard deviation of normal-to normal intervals (SNND) and the root of mean squared difference between adjacent normal heart beat (N-N) intervals (RMSSD) (P>0.05). Conclusion: The results confirmed that the unfavorable air temperatures may considerably affect the physiological responses and the cognitive functions among indoor employees.Therefore, providing them with thermal comfort may improve their performance within indoor environments.