Analysing and modelling train driver performance

Arguments for the importance of contextual factors in understanding human performance have been made extremely persuasive in the context of the process control industries. This paper puts these arguments into the context of the train driving task, drawing on an extensive analysis of driver performance with the Automatic Warning System (AWS). The paper summarises a number of constructs from applied psychological research which are thought to be important in understanding train driver performance. A “Situational Model” is offered as a framework for investigating driver performance. The model emphasises the importance of understanding the state of driver cognition at a specific time (“Now”) in a specific situation and a specific context

Diminished trk A receptor signaling reveals cholinergic‐attentional vulnerability of aging

The cellular mechanisms underlying the exceptional vulnerability of the basal forebrain ( BF ) cholinergic neurons during pathological aging have remained elusive. Here we employed an adeno‐associated viral vector‐based RNA interference ( AAV ‐ RNA i) strategy to suppress the expression of tropomyosin‐related kinase A (trk A ) receptors by cholinergic neurons in the nucleus basalis of M eynert/substantia innominata ( nMB / SI ) of adult and aged rats. Suppression of trk A receptor expression impaired attentional performance selectively in aged rats. Performance correlated with trk A levels in the nMB / SI . trk A knockdown neither affected nMB / SI cholinergic cell counts nor the decrease in cholinergic cell size observed in aged rats. However, trk A suppression augmented an age‐related decrease in the density of cortical cholinergic processes and attenuated the capacity of cholinergic neurons to release acetylcholine ( AC h). The capacity of cortical synapses to release AC h in vivo was also lower in aged/trk A ‐ AAV ‐infused rats than in aged or young controls, and it correlated with their attentional performance. Furthermore, age‐related increases in cortical pro NGF and p75 receptor levels interacted with the vector‐induced loss of trk A receptors to shift NGF signaling toward p75‐mediated suppression of the cholinergic phenotype, thereby attenuating cholinergic function and impairing attentional performance. These effects model the abnormal trophic regulation of cholinergic neurons and cognitive impairments in patients with early A lzheimer's disease. This rat model is useful for identifying the mechanisms rendering aging cholinergic neurons vulnerable as well as for studying the neuropathological mechanisms that are triggered by disrupted trophic signaling. The cellular mechanisms underlying the exceptional vulnerability of the basal forebrain ( BF ) cholinergic neurons during pathological aging have remained elusive. Here we employed an adeno‐associated viral vector‐based RNA interference ( AAV ‐ RNA i) strategy to suppress the expression of trk A receptors by cholinergic neurons in the nucleus basalis of M eynert/substantia innominata (n MB / SI ) of adult and aged rats. This study provides novel evidence that reduced trkA receptors is not sufficient to trigger cholinergic dysfunction. Rather, aging interacts with disrupted trkA signaling to escalate the vulnerability of BF cholinergic neurons and the manifestation of age‐related attentional impairments.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96365/1/ejn12090-sup-0001-SupportingInformation.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/96365/2/ejn12090.pd

How can humans understand their automated cars? HMI principles, problems and solutions

As long as vehicles do not provide full automation, the design and function of the Human Machine Interface (HMI) is crucial for ensuring that the human “driver” and the vehicle-based automated systems collaborate in a safe manner. When the driver is decoupled from active control, the design of the HMI becomes even more critical. Without mutual understanding, the two agents (human and vehicle) will fail to accurately comprehend each other’s intentions and actions. This paper proposes a set of design principles for in-vehicle HMI and reviews some current HMI designs in the light of those principles. We argue that in many respects, the current designs fall short of best practice and have the potential to confuse the driver. This can lead to a mismatch between the operation of the automation in the light of the current external situation and the driver’s awareness of how well the automation is currently handling that situation. A model to illustrate how the various principles are interrelated is proposed. Finally, recommendations are made on how, building on each principle, HMI design solutions can be adopted to address these challenges

Infantile exposure to lead and late-age cognitive decline: Relevance to AD

Background: Early-life lead (Pb) exposure induces overexpression of the amyloid beta precursor protein and its amyloid beta product in older rats and primates. We exposed rodents to Pb during different life span periods and examined cognitive function in old age and its impact on biomarkers associated with Alzheimer\u27s disease (AD). Methods: Morris, Y, and the elevated plus mazes were used. Western blot, quantitative polymerase chain reaction (qPCR), and enzyme-linked immunosorbent assay were used to study the levels of AD biomarkers. Results: Cognitive impairment was observed in mice exposed as infants but not as adults. Overexpression of AD-related genes (amyloid beta precursor protein and β-site amyloid precursor protein cleaving enzyme 1) and their products, as well as their transcriptional regulator—specificity protein 1 (Sp1)—occurred only in older mice with developmental exposure to Pb. Conclusions: A window of vulnerability to Pb neurotoxicity exists in the developing brain that can influence AD pathogenesis and cognitive decline in old age

A Study of the Influence of Sex on Genome Wide Methylation

Sex differences in methylation status have been observed in specific gene-disease studies and healthy methylation variation studies, but little work has been done to study the impact of sex on methylation at the genome wide locus-to-locus level or to determine methods for accounting for sex in genomic association studies. In this study we investigate the genomic sex effect on saliva DNA methylation of 197 subjects (54 females) using 20,493 CpG sites. Three methods, two-sample T-test, principle component analysis and independent component analysis, all successfully identify sex influences. The results show that sex not only influences the methylation of genes in the X chromosome but also in autosomes. 580 autosomal sites show strong differences between males and females. They are found to be highly involved in eight functional groups, including DNA transcription, RNA splicing, membrane, etc. Equally important is that we identify some methylation sites associated with not only sex, but also other phenotypes (age, smoking and drinking level, and cancer). Verification was done through an independent blood cell DNA methylation data (1298 CpG sites from a cancer panel array). The same genomic site-specific influence pattern and potential confounding effects with cancer were observed. The overlapping rate of identified sex affected genes between saliva and blood cell is 81% for X chromosome, and 8% for autosomes. Therefore, correction for sex is necessary. We propose a simple correction method based on independent component analysis, which is a data driven method and accommodates sample differences. Comparison before and after the correction suggests that the method is able to effectively remove the potentially confounding effects of sex, and leave other phenotypes untouched. As such, our method is able to disentangle the sex influence on a genome wide level, and paves the way to achieve more accurate association analyses in genome wide methylation studies

The 5-Choice Continuous Performance Test: Evidence for a Translational Test of Vigilance for Mice

Attentional dysfunction is related to functional disability in patients with neuropsychiatric disorders such as schizophrenia, bipolar disorder, and Alzheimer's disease. Indeed, sustained attention/vigilance is among the leading targets for new medications designed to improve cognition in schizophrenia. Although vigilance is assessed frequently using the continuous performance test (CPT) in humans, few tests specifically assess vigilance in rodents.We describe the 5-choice CPT (5C-CPT), an elaboration of the 5-choice serial reaction (5CSR) task that includes non-signal trials, thus mimicking task parameters of human CPTs that use signal and non-signal events to assess vigilance. The performances of C57BL/6J and DBA/2J mice were assessed in the 5C-CPT to determine whether this task could differentiate between strains. C57BL/6J mice were also trained in the 5CSR task and a simple reaction-time (RT) task involving only one choice (1CRT task). We hypothesized that: 1) C57BL/6J performance would be superior to DBA/2J mice in the 5C-CPT as measured by the sensitivity index measure from signal detection theory; 2) a vigilance decrement would be observed in both strains; and 3) RTs would increase across tasks with increased attentional load (1CRT task<5CSR task<5C-CPT).C57BL/6J mice exhibited superior SI levels compared to DBA/2J mice, but with no difference in accuracy. A vigilance decrement was observed in both strains, which was more pronounced in DBA/2J mice and unaffected by response bias. Finally, we observed increased RTs with increased attentional load, such that 1CRT task<5CSR task<5C-CPT, consistent with human performance in simple RT, choice RT, and CPT tasks. Thus we have demonstrated construct validity for the 5C-CPT as a measure of vigilance that is analogous to human CPT studies

Evidence of Dopaminergic Processing of Executive Inhibition

Inhibition of unwanted response is an important function of the executive system. Since the inhibitory system is impaired in patients with dysregulated dopamine system, we examined dopamine neurotransmission in the human brain during processing of a task of executive inhibition. The experiment used a recently developed dynamic molecular imaging technique to detect and map dopamine released during performance of a modified Eriksen's flanker task. In this study, young healthy volunteers received an intravenous injection of a dopamine receptor ligand (11C-raclopride) after they were positioned in the PET camera. After the injection, volunteers performed the flanker task under Congruent and Incongruent conditions in a single scan session. They were required to inhibit competing options to select an appropriate response in the Incongruent but not in the Congruent condition. The PET data were dynamically acquired during the experiment and analyzed using two variants of the simplified reference region model. The analysis included estimation of a number of receptor kinetic parameters before and after initiation of the Incongruent condition. We found increase in the rate of ligand displacement (from receptor sites) and decrease in the ligand binding potential in the Incongruent condition, suggesting dopamine release during task performance. These changes were observed in small areas of the putamen and caudate bilaterally but were most significant on the dorsal aspect of the body of left caudate. The results provide evidence of dopaminergic processing of executive inhibition and demonstrate that neurochemical changes associated with cognitive processing can be detected and mapped in a single scan session using dynamic molecular imaging