121 research outputs found

    The UnCoVerCPS Verification Approach to Automated Driving

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    There are several benefits for bringing automated vehicles to the road: Possible reduction of traffic accidents, improvement of work life balance and social inclusion of aged or disabled persons, to name just a few. A significant challenge is the validation and verification of automated driving. Classical offline verification approaches require enumeration and discretization of all relevant state variables in all possible driving situations, which results in a state space explosion. A promising approach is the use of online verification techniques pursued in UnCoVerCPS . The methods developed in UnCoVerCPS are generally applicable to many safety critical, cyber physical systems. As a specific use case, we investigate a system which facilitates safe interactions of automated vehicles, leveraging a formal proof on a validated model. By exchanging and negotiating verified maneuver plans, the freedom of collisions and safe operation in general can be guaranteed for the situation at hand. The system design is tailored to make the complete system amenable to verification. An overview is given in fig. 1: The system is decomposed into three layers (green boxes), where each is fulfilling a contract, which guarantees correct operation under specific types of uncertainties. The combination of the three layers enables safe operation under disturbances, input- and parameter uncertainties, non-determinisms of the communication channel as well as nondeterminism of the decisions of cooperation partners. On the lowest layer is the physical vehicle, modeled as a set of nonlinear differential equations with bounded uncertain parameters and disturbances. The second layer is realized by a classical discrete time trajectory tracking controller “TTC”, which stabilizes the vehicle around a given set trajectory, while operating on noisy measurement data. Vehicle model and trajectory tracking controller are considered as a closed loop system by an offline analysis shown at the bottom of fig. 1 (steps 1.Modeling – 6.Verification), which computes bounds on state evolution of the physical system (rather than the model), for a finite set of atomic actions (maneuver database – “MDB”). During online execution, several maneuver planners “MP” assemble the guarantees of the pre-verified atomic actions and use conservative bounds on the environment perception to generate provably safe maneuvers. A timed-automaton (cooperative driving controller – “CDC”) controls negotiation of safe, cooperative maneuvers with other vehicles. It guarantees safe operation even under the assumption of message loss and delays, as well as non-deterministic planning times. This is achieved by prudent switching between cooperative, individual and failsafe maneuvers. In this paper we give an overview of the offline design process, which, besides classical development steps, involves (fig.1, step 4.) sampling possible vehicle actions, (5.) generating a reliable model by testing conformance between the actual physical system and a model with bounded uncertainties and (6.) verifying time in-variant constraints and admissible execution orders of the vehicle actions. Furthermore we focus on the online execution, where maneuver planners and the cooperative driving controller guarantee compliance to time varying constraints. Where “monolithic” verification schemes are hampered by the curse of dimensionality, our modular and layered approach of verifying lower-level, closed-loop subsystems offline and higher-level decision modules online provides formal safety guarantees for the overall system in a feasible manner

    Trail Making Test performance contributes to subjective judgment of visual efficiency in older adults

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    Introduction: The determinant factors that influence self-reported quality of vision have yet to be fully elucidated. This study evaluated a range of contextual information, established psychophysical tests, and in particular, a series of cognitive tests as potentially novel determinant factors.   Materials & Methods: Community dwelling adults (aged 50+) recruited to Wave 1 of The Irish Longitudinal Study on Ageing, excluding those registered blind, participated in this study (N = 5,021). Self-reports of vision were analysed in relation to visual acuity and contrast sensitivity, ocular pathology, visual (Choice Response Time task; Trail Making Test) and global cognition. Contextual factors such as having visited an optometrist and wearing glasses were also considered. Ordinal logistic regression was used to determine univariate and multivariate associations.   Results and Discussion: Poor Trail Making Test performance (Odds ratio, OR = 1.36), visual acuity (OR = 1.72) and ocular pathology (OR = 2.25) were determinant factors for poor versus excellent vision in self-reports. Education, wealth, age, depressive symptoms and general cognitive fitness also contributed to determining self-reported vision.   Conclusions: Trail Making Test contribution to self-reports may capture higher level visual processing and should be considered when using self-reports to assess vision and its role in cognitive and functional health

    Mouse and human genetic analyses associate kalirin with ventral striatal activation during impulsivity and with alcohol misuse

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    Impulsivity is associated with a spectrum of psychiatric disorders including drug addiction. To investigate genetic associations with impulsivity and initiation of drug taking, we took a two-step approach. First, we identified genes whose expression level in prefrontal cortex, striatum and accumbens were associated with impulsive behaviour in the 5-choice serial reaction time task across 10 BXD recombinant inbred (BXD RI) mouse strains and their progenitor C57BL/6J and DBA2/J strains. Behavioural data were correlated with regional gene expression using GeneNetwork (www.genenetwork.org), to identify 44 genes whose probability of association with impulsivity exceeded a false discovery rate of <0.05. We then interrogated the IMAGEN database of 1423 adolescents for potential associations of SNPs in human homologues of those genes identified in the mouse study, with brain activation during impulsive performance in the Monetary Incentive Delay task, and with novelty seeking scores from the Temperament and Character Inventory, as well as alcohol experience. There was a significant overall association between the human homologues of impulsivity-related genes and percentage of premature responses in the MID task and with fMRI BOLD-response in ventral striatum (VS) during reward anticipation. In contrast, no significant association was found between the polygenic scores and anterior cingulate cortex activation. Univariate association analyses revealed that the G allele (major) of the intronic SNP rs6438839 in the KALRN gene was significantly associated with increased VS activation. Additionally, the A-allele (minor) of KALRN intronic SNP rs4634050, belonging to the same haplotype block, was associated with increased frequency of binge drinking

    Poor cerebrovascular function is an early marker of cognitive decline in healthy postmenopausal women

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    Introduction Impairment of cerebrovascular function becomes evident after menopause. No study has yet explored relationships between deficits in cerebrovascular function, cognitive performance, and mood in postmenopausal women. Method Cerebrovascular function was assessed in 80 healthy postmenopausal women by monitoring blood flow velocity (BFV) in the middle and posterior cerebral arteries using transcranial Doppler ultrasound at rest, following a hypercapnic challenge, and during performance of a cognitive test battery; the latter assessed domains of memory and executive functions. Various measures of mood (i.e., Profile of Mood States and Center for Epidemiological Studies Depression Scale) were also assessed. Results Cerebral artery elasticity and BFV responsiveness to cognitive tests (neurovascular coupling) correlated with cognitive performance but not with depressive symptoms or mood states. Mood deficits were related to poor cognitive performance. Conclusion These results highlight the importance of adequate cerebral perfusion for optimized cognitive function in healthy postmenopausal women. Preventative strategies to attenuate accelerated cognitive decline should also consider restoring cerebrovascular function

    Differences in Expression of IQSEC2 Transcript Isoforms in Male and Female Cases with Loss of Function Variants and Neurodevelopmental Disorder

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    Pathogenic hemizygous or heterozygous mutations in the IQSEC2 gene cause X-linked intellectual developmental disorder-1 (XLID1), characterized by a variable phenotype including developmental delay, intellectual disability, epilepsy, hypotonia, autism, microcephaly and stereotypies. It affects both males and females typically through loss of function in males and haploinsufficiency in heterozygous females. Females are generally less affected than males. Two novel unrelated cases, one male and one female, with de novo IQSEC2 variants were detected by trio-based whole exome sequencing. The female case had a previously undescribed frameshift mutation (NM_001111125:c.3300dup; p.Met1101Tyrfs*5), and the male showed an intronic variant in intron 6, with a previously unknown effect (NM_001111125:c.2459+21C&gt;T). IQSEC2 gene expression study revealed that this intronic variant created an alternative donor splicing site and an aberrant product, with the inclusion of 19bp, confirming the pathogenic effect of the intron variant. Moreover, a strong reduction in the expression of the long, but also the short IQSEC2 isoforms, was detected in the male correlating with a more severe phenotype, while the female case showed no decreased expression of the short isoform, and milder effects of the disease. This suggests that the abnormal expression levels of the different IQSEC2 transcripts could be implicated in the severity of disease manifestations.This research was funded by INSTITUTO DE SALUD CARLOS III, institutional project Spain UDP and grant PT20CIII/00009.S

    Breaking bad habits by improving executive function in individuals with obesity

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    Background: Two primary factors that contribute to obesity are unhealthy eating and sedentary behavior. These behaviors are particularly difficult to change in the long-term because they are often enacted habitually. Cognitive Remediation Therapy has been modified and applied to the treatment of obesity (CRT-O) with preliminary results of a randomized controlled trial demonstrating significant weight loss and improvements in executive function. The objective of this study was to conduct a secondary data analysis of the CRT-O trial to evaluate whether CRT-O reduces unhealthy habits that contribute to obesity via improvements in executive function. Method: Eighty participants with obesity were randomized to CRT-O or control. Measures of executive function (Wisconsin Card Sort Task and Trail Making Task) and unhealthy eating and sedentary behavior habits were administered at baseline, post-intervention and at 3 month follow-up. Results: Participants receiving CRT-O demonstrated improvements in both measures of executive function and reductions in both unhealthy habit outcomes compared to control. Mediation analyses revealed that change in one element of executive function performance (Wisconsin Card Sort Task perseverance errors) mediated the effect of CRT-O on changes in both habit outcomes. Conclusion: These results suggest that the effectiveness of CRT-O may result from the disruption of unhealthy habits made possible by improvements in executive function. In particular, it appears that cognitive flexibil ity, as measured by the Wisconsin Card Sort task, is a key mechanism in this process. Improving cognitive flexibility may enable individuals to capitalise on interruptions in unhealthy habits by adjusting their behavior in line with their weight loss goals rather than persisting with an unhealthy choice. Trial registration: The RCT was registered with the Australian New Zealand Registry of Clinical Trials (trial id: ACTRN12613000537752)

    High-flavonoid intake induces cognitive improvement linked to changes in serum brain-derived neurotrophic factor: two randomised,controlled trials

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    BACKGROUND: Recent clinical studies have indicated the beneficial impact of dietary flavonoid intake on human cognitive performance. Although the mechanisms that mediate such improvements are currently unclear, animal and human trial data suggest that changes in neurotrophin expression, and related signalling apparatus, may be involved. OBJECTIVE: To investigate the link between changes in serum brain-derived neurotrophic factor (BDNF) and changes in human cognitive performance following flavonoid intake. METHODS: The relationship between serum levels of BDNF and age, gender, BMI, waist circumference, blood pressure and cognition at baseline, and following flavonoid intake, was investigated in two distinct randomised, controlled clinical trials. Trial 1 was conducted in men and women (aged 26–70 y; consuming an average of 3 portions of fruit and vegetables per day) and delivered high-flavonoid (>15 mg/100 g) or low-flavonoid (<5 mg/100 g) fruit and vegetables and increased intake by 2 portions every 6 weeks. The control arm was habitual diet over the same time frame. Trial 2 was conducted in an older males and female cohort (aged 62–75 y) intervening with a high-flavanol cocoa drink (494 mg total flavanols) and a low-flavanol cocoa drink (23 mg total flavanols) for 12 weeks. RESULTS: Serum BDNF levels increased linearly to the age of 65, after which BDNF levels were found to decrease markedly. All other physiological and anthropometric measurements proved to not be significantly associated with serum BDNF levels (p > 0.05), although higher levels in males compared to females almost achieved significance (p = 0.056). At baseline, higher serum BDNF levels were associated with significantly better global cognition scores, relative to individuals with lower serum levels. In addition, following intervention for 18 weeks, high-flavonoid, but not low-flavonoid, fruit and vegetable intake induced significant improvements in cognitive performance and increases in serum BDNF levels (p = <0.001). Flavanol intervention for 12 weeks also resulted in significant increases in serum BDNF (p = <0.001), and such increases were correlated with improvements in global cognitive performance. CONCLUSION: Increases in global cognition induced by high flavonoid fruit and vegetables, and cocoa flavanols were paralleled by concurrent changes in serum BDNF levels, suggesting a role for BDNF in flavonoid-induced cognitive improvements. Furthermore, we provide further data suggesting that serum BDNF levels may represent a biomarker of cognitive function

    Clinical and imaging correlates of amyloid deposition in dementia with Lewy bodies.

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    BACKGROUND: Amyloid deposition is common in dementia with Lewy bodies, but its pathophysiological significance is unclear. OBJECTIVE: The objective of this study was to investigate the relationship between amyloid deposition and clinical profile, gray matter volume, and brain perfusion in dementia with Lewy bodies. METHODS: Dementia with Lewy bodies (n = 37), Alzheimer's disease (n = 20), and controls (n = 20) underwent a thorough clinical assessment, 3T MRI, and early- and late-phase 18 F-Florbetapir PET-CT to assess cortical perfusion and amyloid deposition, respectively. Amyloid scans were visually categorized as positive or negative. Image analysis was carried out using statistical parametric mapping (SPM) 8. RESULTS: There were no significant differences between amyloid-positive and amyloid-negative dementia with Lewy bodies cases in age (P = .78), overall cognitive impairment (P = .83), level of functional impairment (P = .80), or any other clinical or cognitive scale. There were also no significant differences in hippocampal or gray matter volumes. However, amyloid-positive dementia with Lewy bodies cases had lower medial temporal lobe perfusion (P = .03) than amyloid-negative cases, although a combination of medial temporal lobe perfusion, hippocampal volume, and cognitive measures was unable to accurately predict amyloid status in dementia with Lewy bodies. CONCLUSIONS: Amyloid deposition was not associated with differences in clinical or neuropsychological profiles in dementia with Lewy bodies, but was associated with imaging evidence of medial temporal lobe dysfunction. The presence of amyloid in dementia with Lewy bodies cannot be identified on the basis of clinical and other imaging features and will require direct assessment via PET imaging or CSF. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.Avid, Eli Lilly, NIHR Cambridge and Newcastle Biomedical Research Centr

    Brain Structural Networks Associated with Intelligence and Visuomotor Ability

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    Increasing evidence indicates that multiple structures in the brain are associated with intelligence and cognitive function at the network level. The association between the grey matter (GM) structural network and intelligence and cognition is not well understood. We applied a multivariate approach to identify the pattern of GM and link the structural network to intelligence and cognitive functions. Structural magnetic resonance imaging was acquired from 92 healthy individuals. Source-based morphometry analysis was applied to the imaging data to extract GM structural covariance. We assessed the intelligence, verbal fluency, processing speed, and executive functioning of the participants and further investigated the correlations of the GM structural networks with intelligence and cognitive functions. Six GM structural networks were identified. The cerebello-parietal component and the frontal component were significantly associated with intelligence. The parietal and frontal regions were each distinctively associated with intelligence by maintaining structural networks with the cerebellum and the temporal region, respectively. The cerebellar component was associated with visuomotor ability. Our results support the parieto-frontal integration theory of intelligence by demonstrating how each core region for intelligence works in concert with other regions. In addition, we revealed how the cerebellum is associated with intelligence and cognitive functions

    MET and AKT Genetic Influence on Facial Emotion Perception

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    Background: Facial emotion perception is a major social skill, but its molecular signal pathway remains unclear. The MET/ AKT cascade affects neurodevelopment in general populations and face recognition in patients with autism. This study explores the possible role of MET/AKT cascade in facial emotion perception. Methods: One hundred and eighty two unrelated healthy volunteers (82 men and 100 women) were recruited. Four single nucleotide polymorphisms (SNP) of MET (rs2237717, rs41735, rs42336, and rs1858830) and AKT rs1130233 were genotyped and tested for their effects on facial emotion perception. Facial emotion perception was assessed by the face task of Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT). Thorough neurocognitive functions were also assessed. Results: Regarding MET rs2237717, individuals with the CT genotype performed better in facial emotion perception than those with TT (p = 0.016 by ANOVA, 0.018 by general linear regression model [GLM] to control for age, gender, and education duration), and showed no difference with those with CC. Carriers with the most common MET CGA haplotype (frequency = 50.5%) performed better than non-carriers of CGA in facial emotion perception (p = 0.018, df = 1, F = 5.69, p = 0.009 by GLM). In MET rs2237717/AKT rs1130233 interaction, the C carrier/G carrier group showed better facial emotion perception than those with the TT/AA genotype (p = 0.035 by ANOVA, 0.015 by GLM), even when neurocognitive functions were controlled (p = 0.046 by GLM)
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