Functions of the frontal lobes: relation to executive functions

Training to deal with distractions and conflicting situations in activities of daily living after traumatic brain injury (TBI): Preliminary evidence from a single-case experimental design study

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03958487.

Exploring behavioural and cognitive dysexecutive syndrome in patients with focal prefrontal cortex damage

This study's objectives were to characterize the frequency and profile of behavioral and cognitive dysexecutive syndromes in patients with focal prefrontal cortex damage and how these syndromes overlap. We also examined the contribution of the prefrontal brain regions to these syndromes. Therefore, thirty patients with prefrontal cortex damage and thirty control subjects were compared on their performances using the GREFEX battery assessing the dysexecutive syndromes. The results showed that combined behavioral and cognitive dysexecutive syndrome was observed in 53.33%, while pure cognitive dysexecutive syndrome was observed in 20% and behavioral in 26.67%. Also, almost all behavioral and cognitive dysexecutive disorders discriminated frontal patients from controls. Moreover, correlations and regression analyses between task scores in both domains of dysexecutive syndromes showed that the spectrum of behavioral disorders was differentially associated with cognitive impairment of initiation, inhibition, generation, deduction, coordination, flexibility and the planning process. Furthermore, the patterns of cognitive and behavioral dysexecutive syndrome were both predictors of impairment in daily living activities and loss of autonomy. Finally, frontal regions contributing to different dysexecutive syndromes assessed by MRI voxel lesion symptom analysis indicate several overlapping regions centered on the ventromedial and dorsomedial prefrontal cortex for both domains of dysexecutive syndrome. This study concludes that damage to the frontal structures may lead to a diverse set of changes in both cognitive and behavioral domains which both contribute to loss of autonomy. The association of the ventromedial and dorsomedial prefrontal regions to both domains of dysexecutive syndrome suggests a higher integrative role of these regions in processing cognition and behavior.

Childhood exposure to organophosphate pesticides: Functional connectivity and working memory in adolescents

BACKGROUND

Early life exposure to organophosphate (OP) pesticides is linked with adverse neurodevelopment and brain function in children. However, we have limited knowledge of how these exposures affect functional connectivity, a measure of interaction between brain regions. To address this gap, we examined the association between early life OP pesticide exposure and functional connectivity in adolescents.

METHODS

We administered functional near-infrared spectroscopy (fNIRS) to 291 young adults with measured prenatal or childhood dialkylphosphates (DAPs) in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study, a longitudinal study of women recruited during pregnancy and their offspring. We measured DAPs in urinary samples collected from mothers during pregnancy (13 and 26 weeks) and children in early life (ages 6 months, 1, 2, 3, and 5 years). Youth underwent fNIRS while they performed executive function and semantic language tasks during their 18-year-old visit. We used covariate-adjusted regression models to estimate the associations of prenatal and childhood DAPs with functional connectivity between the frontal, temporal, and parietal regions, and a mediation model to examine the role of functional connectivity in the relationship between DAPs and task performance.

RESULTS

We observed null associations of prenatal and childhood DAP concentrations and functional connectivity for the entire sample. However, when we looked for sex differences, we observed an association between childhood DAPs and functional connectivity for the right interior frontal and premotor cortex after correcting for the false discovery rate, among males, but not females. In addition, functional connectivity appeared to mediate an inverse association between DAPs and working memory accuracy among males.

CONCLUSION

In CHAMACOS, a secondary analysis showed that adolescent males with elevated childhood OP pesticide exposure may have altered brain regional connectivity. This altered neurofunctional pattern in males may partially mediate working memory impairment associated with childhood DAP exposure.

Does the Relationship between Age and Brain Structure Differ in Youth with Conduct Disorder?

Conduct disorder (CD) is characterised by persistent antisocial and aggressive behaviour and typically emerges in childhood or adolescence. Although several authors have proposed that CD is a neurodevelopmental disorder, very little evidence is available about brain development in this condition. Structural brain alterations have been observed in CD, and some indirect evidence for delayed brain maturation has been reported. However, no detailed analysis of age-related changes in brain structure in youth with CD has been conducted. Using cross-sectional MRI data, this study aimed to explore differences in brain maturation in youth with CD versus healthy controls to provide further understanding of the neurodevelopmental processes underlying CD. 291 CD cases (153 males) and 379 healthy controls (160 males) aged 9-18 years (Mage = 14.4) were selected from the European multisite FemNAT-CD study. Structural MRI scans were analysed using surface-based morphometry followed by application of the ENIGMA quality control protocols. An atlas-based approach was used to investigate group differences and test for group-by-age and group-by-age-by-sex interactions in cortical thickness, surface area and subcortical volumes. Relative to healthy controls, the CD group showed lower surface area across frontal, temporal and parietal regions as well as lower total surface area. No significant group-by-age or group-by-age-by-sex interactions were observed on any brain structure measure. These findings suggest that CD is associated with lower surface area across multiple cortical regions, but do not support the idea that CD is associated with delayed brain maturation, at least within the age bracket considered here.

Normative data for executive function tests in an Ecuadorian Waranka minority population

Objective: To generate normative data (ND) for executive functions tests in the Waranka minority population of Ecuador. Method: Four-hundred participants aged 6-17 completed the Symbol-Digit Modalities Test (SDMT), Trail-Making Test (TMT), Modified-Wisconsin Card Sorting Test (M-WCST), and Test of Colors-Words (STROOP). Scores were normed using multiple linear regressions, including age, age2, natural logarithm of mean parent education (MPE), sex, bilingualism, and two-way interactions as predictors. Results: Age by MPE and Age2 by MPE interactions arose for SDMT, so that children with illiterate parents scored lower than those with literate parents. Girls scored higher in SDMT. All TMT and M-WCST scores were influenced by age2. Age by MPE interaction was found for TMT-A, so that children with higher MPE went faster; and age by bilingualism interaction for TMT-B, so that more bilingual children needed less time. Stroop-Word and Color were influenced by age2 by MPE interaction, so that children, while older, scored higher, especially those with higher MPE. Also, age2 by sex interaction arose, so that girls increased scores curvilinearly while boys linearly. Word-Color was influenced by age, while Stroop-interference by age2. Age by MPE interaction was found for MCST-Categories and Perseveration, so that perseverations decreased to then increased, especially in those with illiterate parents. M-WCST-Category scores increased to then decrease later on age in children with illiterate parents. Z-scores calculated through indigenous ND were significantly lower than generated through non-indigenous norms. Conclusions: ND for minority populations are critical since Waranka sample performed worse when using non-indigenous norms for z-score calculation.

A comparison of white matter microstructure and correlates with neuropsychological measures in younger and older adults

OBJECTIVE

With a globally aging population, there is a need to better understand how brain structure relates to function in healthy older and younger adults.

METHODS

34 healthy participants divided into older (17; Mean = 70.9, SD = 5.4) and younger adults (17; Mean = 28.1, SD = 2.8) underwent diffusion-weighted imaging and neuropsychological assessment, including the California Verbal Learning Test 2nd Edition and the Trail Making Test (TMT-A and TMT-B). Differences in white matter microstructure for older and younger adults and the association between DTI metrics (fractional anisotropy, FA; mean diffusivity, MD) and cognitive performance were analyzed using tract-based spatial statistics (p < 0.05, corrected).

RESULTS

Older adults had significantly lower FA and higher MD than younger adults in widespread brain regions. There was a significant negative correlation between executive function (TMT-B) and MD for older adults in the right superior/anterior corona radiata and the corpus callosum. No significant relationship was detected between DTI metrics and executive function in younger adults or with memory performance in either group.

CONCLUSIONS

The findings underscore the need to examine brain-behaviour relationships as a function of age. Future studies should include comprehensive assessments in larger lifespan samples to better understand the aging brain.

Separated at birth: Rediscovering the lost emotions in Luria's Working Brain

Aleksandr Luria repeatedly emphasised the importance of emotions and the right hemisphere in his neuropsychological writings. It is surprising, therefore, that Luria's most influential book, The Working Brain, appears to lack an explicit section on these topics. This is especially notable because of a comment in the book's English-language Introduction, by Karl Pribram, referencing Luria's thoughts about precisely this material. Remarkably, it seems that Luria did write such an explicit chapter, in the original Russian edition. However, in the English-language version, the relevant sections were separated, embedded elsewhere without chapter headings, and altered, presumably following an explicit translation decision. The present paper tracks the nature of these changes and, 50 years later, presents the material for the first time translated and reunited in English, as Luria intended. After the translation, we offer a brief commentary, on the ways in which Luria's ideas were in some respects prescient, and in other respects less well-informed about the brain basis of emotions and the right hemisphere. This reunification offers an interesting time capsule on the opinions of one of neuropsychology's greatest minds, on a topic which Luria admits had, at the time, only a modest empirical foundation.

Exploring the utility of process scores in elucidating the role of cognitive and affective factors that influence verbal fluency performance in Parkinson's disease

OBJECTIVES

Cognitive and affective factors have been implicated in verbal fluency (VF) performance in Parkinson's disease (PD). This exploratory study aimed to investigate the relationships between cognitive and affective variables on traditional ("core") and "process" (error and interval) scores of VF and elucidate unique information these scores may provide regarding mechanisms underlying VF.

METHODS

Sixty-two PD patients without dementia completed clinical neuropsychological examinations consisting of attention, processing speed, language, executive functioning, visuospatial, memory, and mood measures. Hierarchical regression and negative binomial regression analyses were used to evaluate relationships between outcome and predictor variables.

RESULTS

Generativity results revealed that processing speed and working memory explained up to 34% of the variance of total letter fluency responses (p = <.001) and processing speed explained 24% of the variance for total semantic fluency (p = .003). For category switching generativity, only age predicted 20% of the variance (p = .01). Two executive functioning measures were negatively associated with error production over the duration (b = -.055, p = .028; b = -.062, p = .004) and final 45-second interval (b = -.072, p = .003; b = -.044, p = .033) of the category switching task. In the initial 15-second task interval, a positive predictive relationship between error production and indifference apathy (b = .616, p = .044) was demonstrated.

CONCLUSIONS

Findings demonstrate the potential utility of "process" scores in detecting subtle cognitive impairment in Parkinson's disease patients without dementia and tentatively evidence the role of indifference apathy in task initiation.

Moving on with (social) cognition in idiopathic cervical dystonia

OBJECTIVE

Cervical dystonia (CD) is a movement disorder characterized by involuntary muscle contractions causing sustained twisting movements and abnormal postures of the neck and head. Assumed affected neuronal regions are the cortico-striatal-thalamo-cortical circuits, which are also involved in cognitive functioning. Indeed, impairments in different cognitive domains have been found in CD patients. However, to date studies have only investigated a limited range of cognitive functions within the same sample. In particular, social cognition (SC) is often missing from study designs. Hence, we aimed to evaluate a broad range of cognitive functions including SC in CD patients.

METHOD

In the present study 20 idiopathic CD patients and 40 age-, gender-, and IQ-matched healthy controls (HCs) were assessed with tests for non-SC (verbal memory, psychomotor speed, and executive functions) as well as for SC (emotion recognition, Theory of Mind (ToM), and empathy).

RESULTS

CD patients scored on average significantly lower than HC on tests for non-SC, but did not show impairments on any of the tests for SC.

CONCLUSIONS

The current study showed impairments in non-SC in CD, but intact social cognitive functions. These results underline the importance of recognizing non-motor symptoms in idiopathic CD patients, but emphasize a focus on identifying strengths and weaknesses in cognitive functioning as these influence daily life activities.

The contribution of executive functions to the process of return to work after brain injury: A systematic review

Acquired brain injury (ABI) is a worldwide public health issue for its high prevalence rate and the disability it produces. The consequences of ABI, including cognitive deficits, may impact return to work. This review focuses on the association between executive functions (EFs) and return to work after ABI. A systematic review of the literature between 1998 and 2023 was conducted following PRISMA guidelines. The articles were retrieved from the Pubmed, Medline and Web of Science databases. A total of 49 studies were finally selected. Impairments of EF were consistently shown to have a negative impact on return to work after an ABI. There is evidence that specific executive functions and neurobehavioral variables may affect return to work Studies showed a significant theoretical and methodological heterogeneity, representing an important limitation to understand the relation between EFs and work. There is a robust association between EFs and return to work after brain injury. Findings in this systematic review raise the need for further research on the role of specific EF profiles in the process of returning to work after brain damage.

Same, Same but Different? A Multi-Method Review of the Processes Underlying Executive Control

Attention, working memory, and executive control are commonly considered distinct cognitive functions with important reciprocal interactions. Yet, longstanding evidence from lesion studies has demonstrated both overlap and dissociation in their behavioural expression and anatomical underpinnings, suggesting that a lower dimensional framework could be employed to further identify processes supporting goal-directed behaviour. Here, we describe the anatomical and functional correspondence between attention, working memory, and executive control by providing an overview of cognitive models, as well as recent data from lesion studies, invasive and non-invasive multimodal neuroimaging and brain stimulation. We emphasize the benefits of considering converging evidence from multiple methodologies centred on the identification of brain mechanisms supporting goal-driven behaviour. We propose that expanding on this approach should enable the construction of a comprehensive anatomo-functional framework with testable new hypotheses, and aid clinical neuroscience to intervene on impairments of executive functions.

Dysexecutive symptomatology in everyday functioning and academic achievement in adolescents

Background

During the educational stage, academic achievement depends on various social, family, and personal factors. Among the latter, executive skills in everyday life play a significant role in dealing with the academic demands of adolescents. Therefore, the aim of this study is to ascertain the effects of executive symptomatology in everyday functioning on academic achievement in adolescents.

Method

The study involved 910 students aged between 13 and 15 years (M = 14.09, SD = 0.68) from both public and private schools in the Community of Madrid. The DEX, BDEFS-CA, and BRIEF-SR questionnaires were utilised to assess executive difficulties, while grades in language, mathematics, and natural sciences were used as a measure of academic achievement.

Results

The data revealed statistically significant differences in working memory, emotional control, materials organisation, and task completion. In relation to language and natural sciences subjects. In the case of mathematics, emotional control and task completion were significant variables.

Conclusion

Our results indicate that certain executive skills that are manifested in everyday life activities can contribute, albeit in a variable way, to academic achievement in the subjects studied. This aspect is relevant insofar as it allows us to develop preventive interventions based on the executive training of these everyday skills.

Global Sensory Features are Linked to Executive and Attentional Impairments in Autism Spectrum Disorders

Sensory features, executive and attentional impairments are frequently reported in individuals with autism spectrum disorders (ASD). However, little is known about their complex relationships. In this study, we aim to examine the executive and attentional difficulties related to distinct sensory profiles. We identified sensory profiles with a Latent Profile Analysis (LPA) based on scores on the Short Sensory Profile (SSP) questionnaire in 95 children with ASD aged 6 to 17 years. Executive and attention functions were assessed using the Behavior Rating Inventory of Executive Functions (BRIEF) questionnaire and Attention-Deficit Hyperactivity Disorder Rating Scale (ADHD-RS). A three-cluster solution based on raw SSP scores identified a "high'', a "medium" and a "low'' SSP profile. We found a significant relationship between executive functions, attentional skills and the global severity of sensory features, reinforcing findings of previous studies in the literature. A two-cluster solution based on normalized SSP (i.e. equalized for the global severity) identified distinct sensory profiles, mainly discriminated by the score of underresponsive/seeks sensation. We found no significant difference between these two clusters for the BRIEF and ADHD-RS related scores. Our study suggests that the heterogeneity of sensory features in ASD may not be explained by differences in executive and attention functions. Future studies are needed to refine the link between sensory features and executive functions in autism.

Mood moderates the effects of prefrontal tDCS on executive functions: A meta-analysis testing the affective state-dependency hypothesis

BACKGROUND

In recent decades, numerous studies have investigated the effects of transcranial direct current stimulation (tDCS) on cognitive functioning. However, results of these studies frequently display inconsistency and pose challenges regarding replicability. The present work aimed at testing the hypothesis of mood as potential moderator of prefrontal tDCS effects on executive functions (EF). This hypothesis refers to the relationship between mood and EF, as well as to the association of mood with the dorsolateral prefrontal cortex (dlPFC) activity.

METHODS

We conducted a meta-analysis of 11 articles where the dlPFC was stimulated with anodal tDCS, EF were measured, and mood was assessed prior to the stimulation. We then conducted a meta-regression to examine whether mood moderated the tDCS effects on EF.

RESULTS

While no significant effect of tDCS on EF emerged from the meta-analysis, the meta-regression indicated that mood plays a significant role as moderator, with greater tDCS effects on EF in individuals with higher depressive symptoms.

LIMITATIONS

The limited number of studies included, the heterogeneous samples considered, and the limited generalizability to other non-invasive brain stimulation techniques and affective states.

CONCLUSIONS

Findings suggest that evaluating mood prior to stimulation could increase the sensitivity and specificity of tDCS application, and provide the first meta-analytic evidence in favor of the affective state-dependency hypothesis.

Deficits in force production during multifinger tasks demarcate cognitive dysfunction

BACKGROUND

The multifinger force deficit (MFFD) is the decline in force generated by each finger as the number of fingers contributing to an action is increased. It has been shown to associate with cognitive status.

AIMS

The aim was to establish whether a particularly challenging form of multifinger grip dynamometry, that provides minimal tactile feedback via cutaneous receptors and requires active compensation for reaction forces, will yield an MFFD that is more sensitive to cognitive status.

METHODS

Associations between measures of motor function, and cognitive status (Montreal Cognitive Assessment [MoCA]) and latent components of cognitive function (derived from 11 tests using principal component analysis), were estimated cross-sectionally using generalized partial rank correlations. The participants (n  =  62) were community dwelling, aged 65-87.

RESULTS

Approximately half the participants were unable to complete the dynamometry task successfully. Cognitive status demarcated individuals who could perform the task from those who could not. Among those who complied with the task requirements, the MFFD was negatively correlated with MoCA scores-those with the highest MoCA scores tended to exhibit the smallest deficits, and vice versa. There were corresponding associations with latent components of cognitive function.

DISCUSSION

The results support the view that neurodegenerative processes that are a feature of normal and pathological aging exert corresponding effects on expressions of motor coordination-in multifinger tasks, and cognitive sufficiency, due to their dependence on shared neural systems.

CONCLUSIONS

The outcomes add weight to the assertion that deficits in force production during multifinger tasks are sensitive to cognitive dysfunction.

Left and right corticobasal syndrome: comparison of cognitive profiles between metabolic imaging - matched groups

BACKGROUND

Corticobasal syndrome (CBS) is typically asymmetric. Case reports suggest that left-hemisphere CBS (lhCBS) is associated with major language impairment, and right-hemisphere CBS (rhCBS) is associated with major visuospatial deficits, but no group study has ever verified these observations. In our study, we enrolled 49 patients with CBS, classified them as lhCBS or rhCBS based on asymmetry of hypometabolism on brain FDG-PET and compared their cognitive and behavioural profiles.

METHODS

We defined asymmetry of hypometabolism upon visual inspection of qualitative PET images and confirmed it through paired comparison of left- and right-hemisphere FDG uptake values. The two groups were also matched for severity of hypometabolism within the more affected and more preserved hemispheres, to unravel differences in the cognitive profiles ascribable specifically to each hemisphere's functional specializations. All patients were assessed for memory, language, executive and visuospatial deficits, apraxia, neglect, dyscalculia, agraphia and behavioural disturbances.

RESULTS

LhCBS (n. 26) and rhCBS (n. 23) patients did not differ for demographics, disease duration and severity of global cognitive impairment. The two cognitive profiles were largely overlapping, with two exceptions: Digit span forward was poorer in lhCBS, and visual neglect was more frequent in rhCBS.

CONCLUSIONS

After balancing out patients for hemispheric hypometabolism, we did not confirm worse language or visuospatial deficits in, respectively, lhCBS and rhCBS. However, verbal short-term memory was more impaired in lhCBS, and spatial attention was more impaired in rhCBS. Both of these functions reflect the functional specialization of the left and right fronto-parietal pathways, i.e. of the main loci of neurodegeneration in CBS.

Performance monitoring and error detection: The role of mid frontal theta and error-related negativity (ERN) among Indian adolescents from different socioeconomic background

The aim of the study was to investigate the relationship between socioeconomic status (SES) and executive functioning, focusing specifically on performance monitoring, error detection, and their association with mid-frontal theta and error-related negativity (ERN). Employing the widely used flanker task, the research involved two phases with participants aged 10-16 years (15 individuals in the pilot phase and 35 in the second phase). Electroencephalogram (EEG) recordings from distinct brain regions were analyzed during various conditions. The study revealed a notable increase in both absolute and relative theta power at Fcz during the flanker task, with a stronger effect observed during incorrect trials. Furthermore, it underscored the influence of socioeconomic status (SES) on mid-frontal theta, highlighting interactions between SES, gender, and experimental conditions impacting both absolute and relative theta. Intriguingly, the research disclosed a positive correlation between parental occupation and error-related negativity (ERN), as well as between age and ERN. These findings underscore the significance of SES, gender, and age in shaping the neural mechanisms associated with performance monitoring and executive functions. The study contributes valuable insights into the intricate interplay between socio-demographic factors and cognitive processes, shedding light on their impact on goal-directed behaviors and brain activity.

Cross-cultural adaptation and validation of the cooking task to the French-Canadian context: assessing the impact of executive function disorders through cooking activities

BACKGROUND

Acquired brain injury (ABI) often leads to deficits in executive functioning (EF) which is responsible for severe and longstanding disabilities in activities of daily living. The "Cooking Task" (CT), an ecological test of EF involving multi-tasking, was developed in France and exhibits excellent psychometric properties but has not yet been adapted and validated for the French-Canadian context.

OBJECTIVES

Conduct a cross-cultural adaptation and validation of the CT for the French-Canadian context.

METHODS

The CT was translated and adapted by a committee of experts and was validated.

RESULTS

Adaptation-changes were made to the language (e.g., cartable vs classeur), the materials (e.g., measuring cup vs scale), and the measuring units (e.g., ml/cups vs grams). Validation-Preliminary analyses were conducted on 24 participants with an ABI and 17 controls. Construct convergent validity: The French-Canadian-CT discriminates between ABI and control total score on the CT and on most error type categories. Construct known-group validity: French-Canadian-CT scores correlated with another measure of EF deficits (Dysexecutive Questionnaire and Six Elements Task). Inter-rater reliability score for the total error was high (ICC= .84) and results were similar to those obtained for the France-CT.

CONTRIBUTIONS

This study will provide a new ecologically valid tool for clinicians in Canada.

Neuroanatomical Correlates of Cognitive Dysfunction in 22q11.2 Deletion Syndrome

22q11.2 Deletion Syndrome (22q11.2DS), the most common chromosomal microdeletion, presents as a heterogeneous phenotype characterized by an array of anatomical, behavioral, and cognitive abnormalities. Individuals with 22q11.2DS exhibit extensive cognitive deficits, both in overall intellectual capacity and focal challenges in executive functioning, attentional control, perceptual abilities, motor skills, verbal processing, as well as socioemotional operations. Heterogeneity is an intrinsic factor of the deletion's clinical manifestation in these cognitive domains. Structural imaging has identified significant changes in volume, thickness, and surface area. These alterations are closely linked and display region-specific variations with an overall increase in abnormalities following a rostral-caudal gradient. Despite the extensive literature developing around the neurocognitive and neuroanatomical profiles associated with 22q11.2DS, comparatively little research has addressed specific structure-function relationships between aberrant morphological features and deficient cognitive processes. The current review attempts to categorize these limited findings alongside comparisons to populations with phenotypic and structural similarities in order to answer to what degree structural findings can explain the characteristic neurocognitive deficits seen in individuals with 22q11.2DS. In integrating findings from structural neuroimaging and cognitive assessments, this review seeks to characterize structural changes associated with the broad neurocognitive challenges faced by individuals with 22q11.2DS.

Executive and memory dysfunction related to binge drinking in stroke survivors during a 9-year follow-up

Background

Ischemic stroke and heavy alcohol consumption are both known risk factors for cognitive impairment. The issue gains importance because the prevalence of stroke and binge drinking have both increased among working-aged adults. Alarmingly, a recent cross-sectional study suggests the additive negative effects of binge drinking and comorbid brain disease on cognition. However, the long-term cognitive prognosis of the additive effects of stroke and binge drinking on adults remains unknown.

Methods

In this prospective, two-center cohort study, we recruited consecutive 18-65-year-old patients with first-ever ischemic stroke along with demographically matched stroke-free controls. Patients participated in neuropsychological assessment at 6 months, 2 years, and 9 years after stroke, and in neurological assessment at acute care and at 9-year follow-up. Controls participated in a similar follow-up procedure. We examined the association between binge drinking, follow-up time, and long-term cognitive outcomes using repeated-measures analysis of variance.

Results

We included 85 patients who had had their first-ever and only ischemic stroke (mean age 53 years at the incident stroke). Patients were divided into binge-drinking (n = 22) and non-binge-drinking groups (n = 63) based on the shortened version of the Alcohol Use Disorders Identification Test. Follow-up data in healthy controls (n = 31) was used to normalize the patients' test scores for effects of age, sex, and education. We compared cognitive changes between binge-drinking and non-binge-drinking patients over a 9-year follow-up. Non-binge-drinking patients outperformed binge-drinking patients across all follow-up points on most of the executive function tests and in one memory test: binge drinking had a significant main effect both on executive function (the phonemic fluency task, p = 0.002; the Trail Making Test, p = 0.013) and memory (the list learning task, p = 0.002).

Conclusion

Binge drinking was associated with executive and memory dysfunction at three time points over a decade after a first-ever ischemic stroke. Subdiagnostic binge drinking might increase the adverse effects of a first-ever ischemic stroke on executive function and memory, evident over a decade poststroke.

Criminal behaviors: A theory of mind problem?

Theory of mind (ToM) has been addressed in relation to functional alterations of certain brain regions and their connections. The objective is to evaluate ToM in imprisoned criminal offenders and to analyze their relationship with the functions linked to the prefrontal cortex according to their expression in neuropsychological tests. The sample was composed of 52 subjects. 27 committed instrumental homicides and 25 crimes of sale and/or possession of narcotics. A control group was taken, 19 healthy subjects at liberty. The Faux-Pas (FP) and the Reading the Mind in the Eyes tests were used. A neuropsychological battery of executive functions and functions related to the frontal lobes and Hare's Psychopathy Checklist-Revised (PCL-R) was also applied. The criminal groups have comparable performances in all measures. The control group (in freedom) showed higher performance, with statistical significance, in the Faux-Pas test. Moderate negative correlations were found between the FP and the PCL-R. A distinction between affective and cognitive ToM could be affirmed, with people deprived of liberty presenting deficient functioning in the cognitive ToM test. This difference in performance could be linked to the disruptive event with the social norm and not so much with the violent homicide act itself.

Enhancing cognitive control with transcranial magnetic stimulation in subject-specific frontoparietal networks

BACKGROUND

Cognitive control processes, including those involving frontoparietal networks, are highly variable between individuals, posing challenges to basic and clinical sciences. While distinct frontoparietal networks have been associated with specific cognitive control functions such as switching, inhibition, and working memory updating functions, there have been few basic tests of the role of these networks at the individual level.

METHODS

To examine the role of cognitive control at the individual level, we conducted a within-subject excitatory transcranial magnetic stimulation (TMS) study in 19 healthy individuals that targeted intrinsic ("resting") frontoparietal networks. Person-specific intrinsic networks were identified with resting state functional magnetic resonance imaging scans to determine TMS targets. The participants performed three cognitive control tasks: an adapted Navon figure-ground task (requiring set switching), n-back (working memory), and Stroop color-word (inhibition).

OBJECTIVE

Hypothesis: We predicted that stimulating a network associated with externally oriented control [the "FPCN-B" (fronto-parietal control network)] would improve performance on the set switching and working memory task relative to a network associated with attention (the Dorsal Attention Network, DAN) and cranial vertex in a full within-subjects crossover design.

RESULTS

We found that set switching performance was enhanced by FPCN-B stimulation along with some evidence of enhancement in the higher-demand n-back conditions.

CONCLUSION

Higher task demands or proactive control might be a distinguishing role of the FPCN-B, and personalized intrinsic network targeting is feasible in TMS designs.

Guiding patients with traumatic brain injury through the instrumental activities of daily living with the RehaGoal App: a feasibility study

PURPOSE

Individuals with traumatic brain injuries (TBI) often experience executive function impairments that impact activities of daily living. Assistive technologies can help overcome these disabilities and Goal Management Training (GMT) provides an effective therapeutic approach for treating such impairments. To capture the benefits of GMT with assistive technology we developed the RehaGoal App. In this study, we investigate whether combining a modified GMT (mGMT) with the RehaGoal App is feasible in terms of study design, and preliminary evaluation of the attainment of self-defined goals. We also examine if the app produces useful metrics data, tests its usability, and gauges its potential for improving goal attainment.

METHODS

We used a case study design to evaluate four individuals with impairments in executive functions after TBI. They underwent an 8-week mGMT and RehaGoal App intervention to achieve a self-defined goal. To investigate the intervention's feasibility, we collected Goal Attainment Scale (GAS) scores at two-time points, neuropsychological data at study start, System Usability Scale (SUS) scores at study end, and metrics data throughout the study period.

RESULTS

Participant retention and compliance rates were high. All participants improved on GAS. Metrics data was collected successfully and revealed different participant usage behaviours. Overall, the SUS scores of the participants indicated excellent app usability.

CONCLUSIONS

The intervention was feasible but the study design should be modified. Preliminary evaluation of GAS, SUS, and metrics data provided useful insights on user behaviour, app usability, and its role in achieving self-defined goals. The app received overall positive participant ratings.IMPLICATION FOR REHABILITATIONMetric data can be useful as it can give therapists additional opportunities to gain more information about the realization of intervention tasks between the therapy sessions allowing them to use this information to adjust therapy elements.RehaGoal App in combination with a modified GMT may be able to support participants with impairment in executive functions in completing the task of daily living.The study shows that the RehaGoal App is feasible in rehabilitation for a small sample size and that it may be scaled up in the future larger randomized controlled trial.

Basis of executive functions in fine-grained architecture of cortical and subcortical human brain networks

Theoretical models suggest that executive functions rely on both domain-general and domain-specific processes. Supporting this view, prior brain imaging studies have revealed that executive activations converge and diverge within broadly characterized brain networks. However, the lack of precise anatomical mappings has impeded our understanding of the interplay between domain-general and domain-specific processes. To address this challenge, we used the high-resolution multimodal magnetic resonance imaging approach of the Human Connectome Project to scan participants performing 3 canonical executive tasks: n-back, rule switching, and stop signal. The results reveal that, at the individual level, different executive activations converge within 9 domain-general territories distributed in frontal, parietal, and temporal cortices. Each task exhibits a unique topography characterized by finely detailed activation gradients within domain-general territory shifted toward adjacent resting-state networks; n-back activations shift toward the default mode, rule switching toward dorsal attention, and stop signal toward cingulo-opercular networks. Importantly, the strongest activations arise at multimodal neurobiological definitions of network borders. Matching results are seen in circumscribed regions of the caudate nucleus, thalamus, and cerebellum. The shifting peaks of local gradients at the intersection of task-specific networks provide a novel mechanistic insight into how partially-specialized networks interact with neighboring domain-general territories to generate distinct executive functions.

Cognitive reserve, depressive symptoms, obesity, and change in employment status predict mental processing speed and executive function after COVID-19

The risk factors for post-COVID-19 cognitive impairment have been poorly described. This study aimed to identify the sociodemographic, clinical, and lifestyle characteristics that characterize a group of post-COVID-19 condition (PCC) participants with neuropsychological impairment. The study sample included 426 participants with PCC who underwent a neurobehavioral evaluation. We selected seven mental speed processing and executive function variables to obtain a data-driven partition. Clustering algorithms were applied, including K-means, bisecting K-means, and Gaussian mixture models. Different machine learning algorithms were then used to obtain a classifier able to separate the two clusters according to the demographic, clinical, emotional, and lifestyle variables, including logistic regression with least absolute shrinkage and selection operator (LASSO) (L1) and Ridge (L2) regularization, support vector machines (linear/quadratic/radial basis function kernels), and decision tree ensembles (random forest/gradient boosting trees). All clustering quality measures were in agreement in detecting only two clusters in the data based solely on cognitive performance. A model with four variables (cognitive reserve, depressive symptoms, obesity, and change in work situation) obtained with logistic regression with LASSO regularization was able to classify between good and poor cognitive performers with an accuracy and a weighted averaged precision of 72%, a recall of 73%, and an area under the curve of 0.72. PCC individuals with a lower cognitive reserve, more depressive symptoms, obesity, and a change in employment status were at greater risk for poor performance on tasks requiring mental processing speed and executive function. Study registration: www.ClinicalTrials.gov , identifier NCT05307575.

Sleep quality and executive function in a diverse sample of healthy young adults

Few studies examine the relationship between sleep and executive function in diverse samples of young adults. Our research aims to fill this gap by analyzing how self-reported sleep quality is related to informant-rated executive function as a whole and its working memory component in a diverse sample of 29 healthy college students. Using the self-report measure, the Pittsburgh Sleep Quality Index (PSQI), we divided our sample into two groups based on cutoff criteria (score ≥5: poor sleep): good sleep quality (n = 11) and poor sleep quality (n = 18). Participants were on average 20.86 years old. Informants rated participants' executive functioning and working memory using the Frontal Systems Behavior Scale (FrSBe) and Behavior Rating Inventory of Executive Function (BRIEF). Individuals in the poor sleep quality group were reported as having significantly worse executive function and working memory scores. Young adult college students who report less than 7 hours of sleep per night have lower scores on informant measures of working memory and executive function. This study raises awareness about how self-reported sleep experiences are related to other's observation of cognitive abilities in everyday life in a diverse young adult sample.

Development of a generic version of the multiple errands test for severe acquired brain injuries

BACKGROUND

Impairment of executive functions is a frequent and disabling consequence of brain injury. In 1991, Shallice and Burgess elaborated the Multiple Errand Test (MET) to assess everyday troubles associated with this impairment.

OBJECTIVE

Our first aim was to create a generic version of MET (MET-G) readily adaptable to different settings and for retesting. The second aim was to validate the revised version to detect executive impairment in individuals with severe ABI.

METHODS

An inter-professional team of experts in neurorehabilitation created a revised version of MET. Twenty-one patients with sABI (severe Acquired Brain Injury) and a control group of 20 neurologically healthy subjects, took part in the testing of MET-G.

RESULTS

MET-G clearly distinguished people with sABI from healthy controls based on Total error score, task completion, and rule breaking. The test showed good inter-rater reliability and internal consistency.

CONCLUSIONS

The new, generic version of MET was able to differentiate adults with sABI from controls and proved to be a good tool for evaluating executive functions in these patients in daily-life contexts. Indications on how to adapt the test to different contexts and different scoring modalities are provided.

Dopamine Modulates Effective Connectivity in Frontal Cortex

There is increasing evidence that the left lateral frontal cortex is hierarchically organized such that higher-order regions have an asymmetric top-down influence over lower order regions. However, questions remain about the underlying neuroarchitecture of this hierarchical control organization. Within the frontal cortex, dopamine plays an important role in cognitive control functions, and we hypothesized that dopamine may preferentially influence top-down connections within the lateral frontal hierarchy. Using a randomized, double-blind, within-subject design, we analyzed resting-state fMRI data of 66 healthy young participants who were scanned once each after administration of bromocriptine (a dopamine agonist with preferential affinity for D2 receptor), tolcapone (an inhibitor of catechol-O-methyltransferase), and placebo, to determine whether dopaminergic stimulation modulated effective functional connectivity between hierarchically organized frontal regions in the left hemisphere. We found that dopaminergic drugs modulated connections from the caudal middle frontal gyrus and the inferior frontal sulcus to both rostral and caudal frontal areas. In dorsal frontal regions, effectivity connectivity strength was increased, whereas in ventral frontal regions, effective connectivity strength was decreased. These findings suggest that connections within frontal cortex are differentially modulated by dopamine, which may bias the influence that frontal regions exert over each other.

Neuropsychological differential diagnosis of Alzheimer's disease and vascular dementia: a systematic review with meta-regressions

Introduction

Diagnostic classification systems and guidelines posit distinguishing patterns of impairment in Alzheimer's (AD) and vascular dementia (VaD). In our study, we aim to identify which diagnostic instruments distinguish them.

Methods

We searched PubMed and PsychInfo for empirical studies published until December 2020, which investigated differences in cognitive, behavioral, psychiatric, and functional measures in patients older than 64 years and reported information on VaD subtype, age, education, dementia severity, and proportion of women. We systematically reviewed these studies and conducted Bayesian hierarchical meta-regressions to quantify the evidence for differences using the Bayes factor (BF). The risk of bias was assessed using the Newcastle-Ottawa-Scale and funnel plots.

Results

We identified 122 studies with 17,850 AD and 5,247 VaD patients. Methodological limitations of the included studies are low comparability of patient groups and an untransparent patient selection process. In the digit span backward task, AD patients were nine times more probable (BF = 9.38) to outperform VaD patients (β g = 0.33, 95% ETI = 0.12, 0.52). In the phonemic fluency task, AD patients outperformed subcortical VaD (sVaD) patients (β g = 0.51, 95% ETI = 0.22, 0.77, BF = 42.36). VaD patients, in contrast, outperformed AD patients in verbal (β g = -0.61, 95% ETI = -0.97, -0.26, BF = 22.71) and visual (β g = -0.85, 95% ETI = -1.29, -0.32, BF = 13.67) delayed recall. We found the greatest difference in verbal memory, showing that sVaD patients outperform AD patients (β g = -0.64, 95% ETI = -0.88, -0.36, BF = 72.97). Finally, AD patients performed worse than sVaD patients in recognition memory tasks (β g = -0.76, 95% ETI = -1.26, -0.26, BF = 11.50).

Conclusion

Our findings show inferior performance of AD in episodic memory and superior performance in working memory. We found little support for other differences proposed by diagnostic systems and diagnostic guidelines. The utility of cognitive, behavioral, psychiatric, and functional measures in differential diagnosis is limited and should be complemented by other information. Finally, we identify research areas and avenues, which could significantly improve the diagnostic value of cognitive measures.

Validation study of the apathy motivation index in French adults

Objective

Apathy is present in many brain disorders, but it is also prevalent to varying degrees in healthy people. While many tools have been developed to assess levels of apathy in pathology, no standardized measure of apathy in healthy people exists.

Method

Therefore, this study aimed to validate the French version of the Apathy Motivation Index (f-AMI). The results of 729 participants were analyzed using an exploratory factorial analysis.

Results

Preliminary analyses suggested that the three domains of apathy extracted in the original AMI scale-behavioral activation (BA), social motivation (SM), and emotional sensitivity (ES)-could be found also in the f-AMI. A further exploratory analysis showed that a higher number of factors could be extracted, particularly for women. Specifically, both social and emotional factors could be divided into two sub-factors: (1) social motivation toward strangers or toward an acquaintance and (2) self-directed emotional sensitivity directed toward others. Regarding construct validity, the scores of f-AMI were correlated with the French Dimensional Apathy Scale results. Concerning the divergent validity, emotional sensitivity in apathy is different from depression, anhedonia, and fatigue levels.

Conclusion

These results suggest that the f-AMI can be used to assess levels of apathy in healthy adults.

Connectivity by the Frontal Aslant Tract (FAT) Explains Local Functional Specialization of the Superior and Inferior Frontal Gyri in Humans When Choosing Predictive over Reactive Strategies: A Tractography-Guided TMS Study

Predictive and reactive behaviors represent two mutually exclusive strategies in a sensorimotor task. Predictive behavior consists in internally estimating timing and features of a target stimulus and relies on a cortical medial frontal system [superior frontal gyrus (SFG)]. Reactive behavior consists in waiting for actual perception of the target stimulus and relies on the lateral frontal cortex [inferior frontal gyrus (IFG)]. We investigated whether SFG-IFG connections by the frontal aslant tract (FAT) can mediate predictive/reactive interactions. In 19 healthy human volunteers, we applied online transcranial magnetic stimulation (TMS) to six spots along the medial and lateral terminations of the FAT, during the set period of a delayed reaction task. Such scenario can be solved using either predictive or reactive strategies. TMS increased the propensity toward reactive behavior if applied to a specific portion of the IFG and increased predictive behavior when applied to a specific SFG spot. The two active spots in the SFG and IFG were directly connected by a sub-bundle of FAT fibers as indicated by diffusion-weighted imaging (DWI) tractography. Since FAT connectivity identifies two distant cortical nodes with opposite functions, we propose that the FAT mediates mutually inhibitory interactions between SFG and IFG to implement a "winner takes all" decisional process. We hypothesize such role of the FAT to be domain-general, whenever competition occurs between internal predictive and external reactive behaviors. Finally, we also show that anatomic connectivity is a powerful factor to explain and predict the spatial distribution of brain stimulation effects.SIGNIFICANCE STATEMENT We interact with sensory cues adopting two main mutually-exclusive strategies: (1) trying to anticipate the occurrence of the cue or (2) waiting for the GO-signal to be manifest and react to it. Here, we showed, by using noninvasive brain stimulation [transcranial magnetic stimulation (TMS)], that two specific cortical regions in the superior frontal gyrus (SFG) and the inferior frontal gyrus (IFG) have opposite roles in facilitating a predictive or a reactive strategy. Importantly these two very distant regions but with highly interconnected functions are specifically connected by a small white matter bundle, which mediates the direct competition and exclusiveness between predictive and reactive strategies. More generally, implementing anatomic connectivity in TMS studies strongly reduces spatial noise.

Inhibitory control associated with the neural mechanism of joint attention in preschoolers: An fNIRS evidence

Joint attention (JA) is fundamental to the development of children's social functioning; both its response and initiation are closely related to executive function (EF), but the relationship between JA and EF has been relatively rarely studied. The present study aimed to investigate the between-condition differences in brain activation and synchronization of JA under four conditions: (1) stranger-Initiating Joint Attention (Stranger-IJA); (2) teacher-Initiating Joint Attention (Teacher-IJA); (3) stranger-Responding to Joint Attention (Stranger-RJA); and (4) teacher-Responding to Joint Attention (Teacher-RJA). It also aimed to explore the relationships between neuroimaging data and children's inhibitory control levels. To address these two goals, the present study employed 41 (aged 58.61 ± 8.64 months, 24 boys) preschool children through behavioral and functional Near-Infrared Spectroscopy (fNIRS) brain imaging assessment to measure children's EF and brain function under JA, respectively. The results revealed that: (1) a significantly higher prefrontal cortex (PFC) activation was triggered in IJA than RJA; (2) a significantly higher brain activation was triggered in JA with a stranger than with a teacher; (3) a significantly higher index of synchronization asymmetry was evoked in the left and right PFC during interaction with the teacher than with the stranger; and (4) preschoolers' brain activation and synchronization were correlated with their inhibitory control level. The findings advance our understanding of preschoolers' social cognitive development with a biological aspect, offer an opportunity to understand the potential risk of the neural disorder in preschoolers, and provide a basis and insight for preventing neural developmental disorders.

Sex differences in cognition and structural covariance-based morphometric connectivity: evidence from 28,000+ UK Biobank participants

There is robust evidence for sex differences in domain-specific cognition, where females typically show an advantage for verbal memory, whereas males tend to perform better in spatial memory. Sex differences in brain connectivity are well documented and may provide insight into these differences. In this study, we examined sex differences in cognition and structural covariance, as an index of morphometric connectivity, of a large healthy sample (n = 28,821) from the UK Biobank. Using T1-weighted magnetic resonance imaging scans and regional cortical thickness values, we applied jackknife bias estimation and graph theory to obtain subject-specific measures of structural covariance, hypothesizing that sex-related differences in brain network global efficiency, or overall covariance, would underlie cognitive differences. As predicted, females demonstrated better verbal memory and males showed a spatial memory advantage. Females also demonstrated faster processing speed, with no observed sex difference in executive functioning. Males showed higher global efficiency, as well as higher regional covariance (nodal strengths) in both hemispheres relative to females. Furthermore, higher global efficiency in males mediated sex differences in verbal memory and processing speed. Findings contribute to an improved understanding of how biological sex and differences in cognition are related to morphometric connectivity as derived from graph-theoretic methods.

Psychophysiology of Monotonous Driving, Fatigue and Sleepiness in Train and Non-Professional Drivers: Driver Safety Implications

Fatigue and sleepiness are complex bodily states associated with monotony as well as physical and cognitive impairment, accidents, injury, and illness. Moreover, these states are often characteristic of professional driving. However, most existing work has focused on motor vehicle drivers, and research examining train drivers remains limited. As such, the present study psychophysiologically examined monotonous driving, fatigue, and sleepiness in a group of passenger train drivers and a group of non-professional drivers. Sixty-three train drivers and thirty non-professional drivers participated in the present study, which captured 32-lead electroencephalogram (EEG) data during a monotonous driving task. Fatigue and sleepiness were self-evaluated using the Pittsburgh Sleep Quality Index, the Epworth Sleepiness Scale, the Karolinksa Sleepiness Scale, and the Checklist of Individual Strength. Unexpectedly, fatigue and sleepiness scores did not significantly differ between the groups; however, train drivers generally scored lower than non-professional drivers, which may be indicative of individual and/or industry attempts to reduce fatigue. Across both groups, fatigue and sleepiness scores were negatively correlated with theta, alpha, and beta EEG variables clustered towards the fronto-central and temporal regions. Broadly, these associations may reflect a monotony-associated blunting of neural activity that is associated with a self-reported fatigue state.

Comparing the Symptomatology of Post-stroke Depression with Depression in the General Population: A Systematic Review

Previous research into the phenomenological differences of post-stroke depression (PSD) has typically focused on comparisons of symptom profiles between stroke and non-stroke population controls. This systematic review aimed to synthesize these findings with results from other methodological approaches that contribute to an understanding of phenomenological differences. Articles were identified via a systematic search of seven databases and additional manual searching. A narrative synthesis approach was adopted because of the high methodological heterogeneity. Twelve articles comparing the symptomatology of depression between stroke and non-stroke controls were included. Three distinct methodological approaches, relevant to the aim, were identified: comparisons of profiles among groups with similar overall depression severity, comparisons of the strengths of correlations between a symptom and depression, and comparisons of latent symptom severity. The symptomatology of depression was generally similar between the groups, including somatic symptoms, despite the hypothesized interference of comorbid physical stroke effects. Despite high heterogeneity, there was a tentative indication that post-stroke depression manifests with comparatively less severe/prevalent anhedonia. Possible mechanisms for the observed similarities and differences are explored, including suggestions for future research.

The Role of Apathy in Spontaneous Verbal and Nonverbal Behaviors: A Transdiagnostic Pilot Study in Neurodegeneration

BACKGROUND

Apathy, characterized by a quantifiable reduction in motivation or goal-directed behavior, is a multidimensional syndrome that has been observed across many neurodegenerative diseases.

OBJECTIVE

To develop a novel task measuring spontaneous action initiation (ie, a nonverbal equivalent to spontaneous speech tasks) and to investigate the association between apathy and executive functions such as the voluntary initiation of speech and actions and energization (ie, ability to initiate and sustain a response).

METHOD

We compared the energization and executive functioning performance of 10 individuals with neurodegenerative disease and clinically significant apathy with that of age-matched healthy controls (HC). We also investigated the association between self-reported scores on the Apathy Evaluation Scale (AES) and performance on energization tasks.

RESULTS

The individuals with apathy made significantly fewer task-related actions than the HC on the novel spontaneous action task, and their scores on the AES were negatively correlated with spontaneous task-related actions, providing preliminary evidence for the task's construct validity. In addition, the individuals with apathy performed more poorly than the HC on all of the energization tasks, regardless of task type or stimulus modality, suggesting difficulty in sustaining voluntary responding over time. Most of the tasks also correlated negatively with the AES score. However, the individuals with apathy also performed more poorly on some of the executive function tasks, particularly those involving self-monitoring.

CONCLUSION

Our work presents a novel experimental task for measuring spontaneous action initiation-a key symptom of apathy-and suggests a possible contribution of apathy to neuropsychological deficits such as poor energization.

Executive functioning as a moderator of flossing behaviour among young adults: a temporal self-regulation theory perspective

Background

Flossing among young adults is often infrequent and barriers not completely understood. One explanation concerns the capacity for executive functioning (EF) during the self-regulation of behaviour.

Methods

Using Temporal Self-Regulation Theory (TST) as a framework to explore EF, young adults from Norwegian universities completed a survey that measured monthly flossing frequency, flossing-related intentions and behavioural prepotency (BP), and EF using the Behaviour Rating Inventory of Executive Function - Adult Version (BRIEF-A).

Results

Data from 362 participants were analysed. The TST-model explained a substantial proportion of variance in monthly flossing (R2 = 0.74), and flossing was associated directly with intention and BP, and interactions between intention and both BP and global-EF. Sub-domains of EF were explored using the same model, revealing that behavioural regulation processes, specifically those related to emotional control and shifting between tasks, offered better fit. Simple slopes revealed that moderation effects were only present at lower levels of BP.

Conclusion

EF plays a role in moderating the translation of intentions into flossing behaviour. Specifically, emotional control and task-shifting appear to be influential, and this influence increases when habitual and environmental support (i.e. BP) is reduced. Overcoming EF-barriers may represent a key step in establishing flossing behaviours.

Mental flexibility depends on a largely distributed white matter network: Causal evidence from connectome-based lesion-symptom mapping

Mental flexibility (MF) refers to the capacity to dynamically switch from one task to another. Current neurocognitive models suggest that since this function requires interactions between multiple remote brain areas, the integrity of the anatomic tracts connecting these brain areas is necessary to maintain performance. We tested this hypothesis by assessing with a connectome-based lesion-symptom mapping approach the effects of white matter lesions on the brain's structural connectome and their association with performance on the trail making test, a neuropsychological test of MF, in a sample of 167 first unilateral stroke patients. We found associations between MF deficits and damage of i) left lateralized fronto-temporo-parietal connections and interhemispheric connections between left temporo-parietal and right parietal areas; ii) left cortico-basal connections; and iii) left cortico-pontine connections. We further identified a relationship between MF and white matter disconnections within cortical areas composing the cognitive control, default mode and attention functional networks. These results for a central role of white matter integrity in MF extend current literature by providing causal evidence for a functional interdependence among the regional cortical and subcortical structures composing the MF network. Our results further emphasize the necessity to consider connectomics in lesion-symptom mapping analyses to establish comprehensive neurocognitive models of high-order cognitive functions.

Trajectories of cortical structures associated with stress across adolescence: a bivariate latent change score approach

BACKGROUND

Stress exposure in childhood and adolescence has been linked to reductions in cortical structures and cognitive functioning. However, to date, most of these studies have been cross-sectional, limiting the ability to make long-term inferences, given that most cortical structures continue to develop through adolescence.

METHODS

Here, we used a subset of the IMAGEN population cohort sample (N = 502; assessment ages: 14, 19, and 22 years; mean age: 21.945 years; SD = 0.610) to understand longitudinally the long-term interrelations between stress, cortical development, and cognitive functioning. To these ends, we first used a latent change score model to examine four bivariate relations - assessing individual differences in change in the relations between adolescent stress exposure and volume, surface area, and cortical thickness of cortical structures, as well as cognitive outcomes. Second, we probed for indirect neurocognitive effects linking stress to cortical brain structures and cognitive functions using rich longitudinal mediation modeling.

RESULTS

Latent change score modeling showed that greater baseline adolescence stress at age 14 predicted a small reduction in the right anterior cingulate volume (Std. β = -.327, p = .042, 95% CI [-0.643, -0.012]) and right anterior cingulate surface area (Std. β = -.274, p = .038, 95% CI [-0.533, -0.015]) across ages 14-22. These effects were very modest in nature and became nonsignificant after correcting for multiple comparisons. Our longitudinal analyses found no evidence of indirect effects in the two neurocognitive pathways linking adolescent stress to brain and cognitive outcomes.

CONCLUSION

Findings shed light on the impact of stress on brain reductions, particularly in the prefrontal cortex that have consistently been implicated in the previous cross-sectional studies. However, the magnitude of effects observed in our study is smaller than that has been reported in past cross-sectional work. This suggests that the potential impact of stress during adolescence on brain structures may likely be more modest than previously noted.

Sensitivity and specificity of the ECAS in identifying executive function and social cognition deficits in MND

Objective: Motor neurone disease [MND] encompasses broad cognitive impairments, which are not fully captured by most screening tools. This study evaluated the specificity and sensitivity of the Edinburgh Cognitive and Behavioral ALS Screen [ECAS] in detecting impairments in executive function and social cognition. Methods: Participants (MND = 64; Healthy Controls = 45) completed the ECAS and standard neuropsychology tests of executive function and social cognition. Sensitivity and specificity of the ECAS were assessed at three levels (ALS-Specific score, executive function domain score, individual subtests: social cognition, inhibition, working memory, alternation). Results: MND patients were impaired on standard social cognition, initiation, visuomotor alternation, and verbal learning tests but not on inhibition or working memory tests, relative to controls. ECAS results revealed that the ALS-Specific score was high in specificity but low-to-moderately sensitive in identifying social cognition, inhibition, and working memory deficits, and that both sensitivity and specificity were high for identifying alternation deficits. The ECAS executive function domain score was high in specificity but poor in sensitivity for all four executive function domain subtests. The individual ECAS subtests were highly specific with good sensitivity, but the social cognition subtest lacked sensitivity. Conclusions: Impairments in social cognition may go undetected when using the ECAS as a screening tool. Thus, social cognition may need to be considered as a standalone component, distinct from the other executive functions. In addition, the test itself may need to be adjusted to encompass other aspects of social cognition that are affected in MND.Key messagesCognitive screening tools are key to detect cognitive changes in MND, with the domains most affected being executive functions, language, and social cognition.The ECAS measure, developed for MND, has good specificity but lacks sensitivity to impairments in social cognition.Clinical implications are that cognitive impairments in social cognition may not be identified in MND patients by the ECAS.Adjustment to the ECAS cognitive screening tool widely-used in MND is suggested.

Untreated if unrecognized: A cognitive profile of sustained subjective executive dysfunctions in COVID-19

& STATEMENT OF IMPACTSARS-COV-2 infection can result in acute and long-lasting cognitive complaints, causing ongoing impairments in daily life which poses a challenge to society. Consequently, the evaluation and characterization of cognitive complaints, specifically in the domain of executive functions (EFs) affecting daily life, is imperative in formulating an effective neuropsychological response.In total 442 participants aged 18-65+ years from the Netherlands, Germany, Mexico, and Spain were included in an online questionnaire. Among others, the questionnaire consisted of demographics, the Behavior Rating Inventory of Executive Functioning for Adults (BRIEF-A), measures of subjective disease progression severity and experienced subjective impairment in daily activities. To assess whether daily life activities are affected by EF impairments, the main BRIEF-A composite score (GEC) was analyzed. To determine whether disease-related COVID-19 factors predict EFs complaints in daily life, a stepwise regression analysis was performed with i) experienced disease severity, ii) time since disease, and iii) health risk factor as predictors.The study revealed noteworthy differences in the occurrence of EFs problems in daily life between both groups, as indicated by the GEC, which exhibited a medium effect size even 6 months post-COVID-19 diagnosis even in mild disease progression. The scores of the BRIEF-A subscales follow a domain-specific profile, and includes clinically relevant impairments in: Working memory, Plan/Organize, Task Monitor, Shift, which are affected by the experienced severity of the disease. This cognitive profile has important implications for targeted cognitive training in rehabilitation and has the potential for an applicability to other viruses as well.

Translation, cross-cultural adaptation and validation of the 10-item Weekly Calendar Planning Activity in Spanish-speaking ABI patients: a multicenter study

We present the process of translation, adaptation, and validation in the Spanish context of the 10-item version of the Weekly Calendar Planning Activity (WCPA-10), a performance-based measure of cognitive instrumental activities of daily living (C-IADL). The study consisted of two phases: I) translation/cultural adaptation of the WCPA, conducted by professional bilingual translators, a panel of experts, and a pilot study, and II) validation in a sample of 42 acquired brain injury patients (ABI) and 42 healthy participants (HC). WCPA primary outcomes showed expected convergent/discriminant validity patterns with socio-demographical and clinical variables and cognitive processes identifying those WCPA outcomes that best predicted executive and memory deficits measured with a battery of traditional neuropsychological tests. In addition, performance on the WCPA was a significant predictor of everyday functioning over variables such as socio-demographics or global cognition when measured with traditional tests. External validity was established by the WCPA's ability to identify everyday cognitive deficits in ABI patients compared to HC, even in those with subtle cognitive impairment based on neuropsychological tests. The Spanish WCPA-10 seems an appropriate and sensitive assessment tool to identify cognitive-functional impairment in ABI-patients, even those with subtle cognitive impairment. The results also highlight the relevance of this kind of test, as they indicate a better prediction of patients' real-world functioning than traditional neuropsychological tests.

Biometals in Alzheimer disease: emerging therapeutic and diagnostic potential of molybdenum and iodine

The current ageing trend of the world population has, in part, accounted for Alzheimer disease (AD) being a public health issue in recent times. Although some progress has been made in clarifying AD-related pathophysiological mechanisms, effective intervention is still elusive. Biometals are indispensable to normal physiological functions of the human body-for example, neurogenesis and metabolism. However, their association with AD remains highly controversial. Copper (Cu) and zinc (Zn) are biometals that have been investigated at great length in relation to neurodegeneration, whereas less attention has been afforded to other trace biometals, such as molybdenum (Mo), and iodine. Given the above context, we reviewed the limited number of studies that have evidenced various effects following the usage of these two biometals in different investigative models of AD. Revisiting these biometals via thorough investigations, along with their biological mechanisms may present a solid foundation for not only the development of effective interventions, but also as diagnostic agents for AD.

Linking individual variability in functional brain connectivity to polygenic risk in major depressive disorder

BACKGROUND

Major depressive disorder (MDD) is a highly heterogeneous disease, which brings great difficulties to clinical diagnosis and therapy. Its mechanism is still unknown. Prior neuroimaging studies mainly focused on mean differences between patients and healthy controls (HC), largely ignoring individual differences between patients.

METHODS

This study included 112 MDD patients and 93 HC subjects. Resting-state functional MRI data were obtained to examine the patterns of individual variability of brain functional connectivity (IVFC). The genetic risk of pathways including dopamine, 5-hydroxytryptamine (5-HT), norepinephrine (NE), hypothalamic-pituitary-adrenal (HPA) axis, and synaptic plasticity was assessed by multilocus genetic profile scores (MGPS), respectively.

RESULTS

The IVFC pattern of the MDD group was similar but higher than that in HCs. The inter-network functional connectivity in the default mode network contributed to altered IVFC in MDD. 5-HT, NE, and HPA pathway genes affected IVFC in MDD patients. The age of onset, duration, severity, and treatment response, were correlated with IVFC. IVFC in the left ventromedial prefrontal cortex had a mediating effect between MGPS of the 5-HT pathway and baseline depression severity.

LIMITATIONS

Environmental factors and differences in locations of functional areas across individuals were not taken into account.

CONCLUSIONS

This study found MDD patients had significantly different inter-individual functional connectivity variations than healthy people, and genetic risk might affect clinical manifestations through brain function heterogeneity.

A true reflection of executive functioning or a representation of task-specific variance? Re-evaluating the unity/diversity framework

The unity/diversity framework, originally published by Miyake et al. (2000) has become the most cited model of executive functioning. Consequently, when researchers operationalise executive function (EF) they often exclusively assess the three "core" EFs: updating, shifting, and inhibition. However, rather than core EFs representing domain general cognitive abilities, these three EFs may instead represent specific procedural skills from the overlapping methodologies of the tasks selected. In this study, we conducted a confirmatory factor analysis (CFA) which showed both the traditional three-factor and nested-factor model from the unity/diversity framework failed to reach satisfactory levels of fit. Subsequently, an exploratory factor analysis supported a three-factor model reflecting: an expanded working memory factor, a combined shifting/inhibition factor representing cognitive flexibility, and a factor comprised solely of the Stroop task. These results demonstrate that working memory remains the most robustly operationalised EF construct, whereas shifting and inhibition may represent task-specific mechanisms of a broader domain-general cognitive flexibility factor. Ultimately, there is little evidence to suggest that updating, shifting, and inhibition encapsulates all core EFs. Further research is needed to develop an ecologically valid model of executive functioning that captures the cognitive abilities associated with real world goal-directed behaviour.

Comparison of Cerebral Blood Flow in Regions Relevant to Cognition After Enzalutamide, Darolutamide, and Placebo in Healthy Volunteers: A Randomized Crossover Trial

BACKGROUND

Off-target central nervous system (CNS) effects are associated with androgen receptor (AR)-targeting treatments for prostate cancer. Darolutamide is a structurally distinct AR inhibitor with low blood-brain barrier penetration.

OBJECTIVE

We compared cerebral blood flow (CBF) in grey matter and specific regions related to cognition after darolutamide, enzalutamide, or placebo administration, using arterial spin-label magnetic resonance imaging (ASL-MRI).

METHODS

This phase I, randomized, placebo-controlled, three-period crossover study administered single doses of darolutamide, enzalutamide, or placebo to 23 healthy males (aged 18-45 years) at 6-week intervals. ASL-MRI mapped CBF 4 h post-treatment. Treatments were compared using paired t-tests.

RESULTS

Drug concentrations during scans confirmed similar unbound exposure of darolutamide and enzalutamide, with complete washout between treatments. A significant localized 5.2% (p = 0.01) and 5.9% (p < 0.001) CBF reduction in the temporo-occipital cortices was observed for enzalutamide versus placebo and versus darolutamide, respectively, with no significant differences for darolutamide versus placebo. Enzalutamide reduced CBF in all prespecified regions, with significant reductions versus placebo (3.9%, p = 0.045) and versus darolutamide (4.4%, p = 0.037) in the left and right dorsolateral prefrontal cortices, respectively. Darolutamide showed minimal changes in CBF versus placebo in cognition-relevant regions.

CONCLUSIONS

Darolutamide did not significantly alter CBF, consistent with its low blood-brain barrier penetration and low risk of CNS-related adverse events. A significant reduction in CBF was observed with enzalutamide. These results may be relevant to cognitive function with early and extended use of second-generation AR inhibitors, and warrant further investigation in patients with prostate cancer.

TRIAL REGISTRATION NUMBER

NCT03704519; date of registration: October 2018.

Normative data for the verb fluency test in the adult French-Quebec population and validation study in mild cognitive impairment

Verbal fluency tests are used to assess executive functions and language. The verb fluency test has proven successful in distinguishing healthy individuals (HCs) from participants with pathological conditions. However, few normative and psychometric studies have been published for the verb fluency test. The aim of Study 1 was to provide normative data in the adult population of French Québec for the verb fluency test. The aim of Study 2 was to determine its discriminant validity and test-retest reliability. The normative sample consisted of 424 HCs aged 50-92 years. Multiple linear regressions were used to generate equations for calculating Z-scores. To assess discriminant validity, the performance of 46 HCs was compared with that of 46 participants with mild cognitive impairment (MCI). To determine test-retest reliability, the test was administered twice, 3 months apart, to a group of 25 HCs. Age, sex, and education level were significantly related to performance on the test. The test distinguished the performance of HCs from that of participants with MCI. Test-retest analysis showed that scores had good stability over time. Norms and psychometric data for the verb fluency test will help clinicians and researchers better identify executive and language impairments associated with pathological conditions.

Increased cortical structural covariance correlates with anhedonia in schizophrenia

Anhedonia is a common symptom in schizophrenia and is closely related to poor functional outcomes. Several lines of evidence reveal that the orbitofrontal cortex plays an important role in anhedonia. In the present study, we aimed to investigate abnormalities in structural covariance within the orbitofrontal subregions, and to further study their role in anticipatory and consummatory anhedonia in schizophrenia. T1 images of 35 schizophrenia patients and 45 healthy controls were obtained. The cortical thickness of 68 cerebral regions parcellated by the Desikan-Killiany (DK) atlas was calculated. The structural covariance within the orbitofrontal subregions was calculated in both schizophrenia and healthy control groups. Stepwise linear regression was performed to examine the relationship between structural covariance and anhedonia in schizophrenia patients. Patients with schizophrenia exhibited higher structural covariance between the left and right medial orbitofrontal thickness, the left lateral orbitofrontal thickness and left pars orbitalis thickness compared to healthy controls (p < 0.05, FDR corrected). This results imply that the increased structural covariance in orbitofrontal thickness may be involved in the process of developing anhedonia in schizophrenia. The result indicated that the increased structural covariance between the left and right medial orbitofrontal thickness might be a protective factor for anticipatory pleasure (B' = 0.420, p = 0.012).

Medial Prefrontal Cortex Serotonin Input Regulates Cognitive Flexibility in Mice

The medial prefrontal cortex (mPFC) regulates cognitive flexibility and emotional behavior. Neurons that release serotonin project to the mPFC, and serotonergic drugs influence emotion and cognition. Yet, the specific roles of endogenous serotonin release in the mPFC on neurophysiology and behavior are unknown. We show that axonal serotonin release in the mPFC directly inhibits the major mPFC output neurons. In serotonergic neurons projecting from the dorsal raphe to the mPFC, we find endogenous activity signatures pre-reward retrieval and at reward retrieval during a cognitive flexibility task. In vivo optogenetic activation of this pathway during pre-reward retrieval selectively improved extradimensional rule shift performance while inhibition impaired it, demonstrating sufficiency and necessity for mPFC serotonin release in cognitive flexibility. Locomotor activity and anxiety-like behavior were not affected by either optogenetic manipulation. Collectively, our data reveal a powerful and specific modulatory role of endogenous serotonin release from dorsal raphe-to-mPFC projecting neurons in cognitive flexibility.

The assessment of executive functions to test the integrity of the nigrostriatal network: A pilot study

Background

Parkinson’s disease (PD) is a chronic neurodegenerative disorder characterized by motor and non-motor symptoms. The latter mainly include affective, sleep, and cognitive deficits. Non-demented PD patients often demonstrate impairments in several executive domains following neuropsychological evaluation. The current pilot study aims at assessing the discriminatory power of the Frontal Assessment Battery-15 (FAB15) in differentiating (i) non-demented PD patients and healthy controls and (ii) PD patients with more and less pronounced motor symptoms.

Methods

Thirty-nine non-demented early-stage PD patients in the “on” dopamine state (26 females, mean age = 64.51 years, SD = 6.47, mean disease duration = 5.49 years, SD = 2.28) and 39 healthy participants (24 females, mean age = 62.60 years, SD = 5.51) were included in the study. All participants completed the FAB15. Motor symptoms of PD patients were quantified via the Unified Parkinson’s Disease Rating Scale-Part III (UPDRS-Part III) and Hoehn and Yahr staging scale (H&amp;Y).

Results

The FAB15 score, adjusted according to normative data for sex, age, and education, proved to be sufficiently able to discriminate PD patients from healthy controls (AUC = 0.69 [95% CI 0.60–0.75], SE = 0.06, p = 0.04, optimal cutoff = 11.29). Conversely, the battery lacked sufficient discriminative capability to differentiate PD patients based on the severity of motor symptoms.

Conclusion

The FAB15 may be a valid tool for distinguishing PD patients from healthy controls. However, it might be less sensitive in identifying clinical phenotypes characterized by visuospatial impairments resulting from posteroparietal and/or temporal dysfunctions. In line with previous evidence, the battery demonstrated to be not expendable in the clinical practice for monitoring the severity of PD-related motor symptoms.