Perceptual impact of environmental factors in sighted and visually impaired individuals

To a visually impaired individual the physical world presents many challenges. For a person with impaired sight, wayfinding through a complex environment is fraught with dangers, both actual and imagined. The current generation of mobility aids have the possibility of addressing a broad range of physical issues through technological solutions. The perception of difficulty however, can mean that many visually impaired individuals are fearful or uncomfortable about independent mobility or travel. In this context it becomes necessary to discover exactly what environments, environmental factors or items constitute a ‘perception of difficulty’ in the individuals mental landscape and may trigger a negative response before they interact with the physical environment. This paper reports on research, which sought to ascertain what levels of perceptual difficulties specific environments and factors presented to individuals. The research was conducted with both visually impaired and sighted groups and compared differences and similarities in perceptual difficulty between these two groups

Vasopressinergic modulation of stress responses in the central amygdala of the Roman high-avoidance and low-avoidance rat

The central nucleus of the amygdala (CEA) is selectively involved in the passive component of the behavioral (immobility) and the accompanying parasympathetic response during conditioned, stressful environmental challenges. Vasopressinergic mechanisms in the brain seem to play a role in these stress responses. The effects of the neuropeptides arginine-8-vasopressin (AVP) and oxytocin (OXT) on modulating CEA activity during conditioned stress of inescapable footshock were studied in male Roman high-avoidance (RHA/Verh) and low-avoidance (RLA/Verh) rats, psychogenetically selected on the basis of shuttle-box acquisition behavior. In RLA/Verh rats, the cardiac and behavioral responses to the conditioned emotional stressor were bradycardia and immobility, suggesting an important role for the CEA in these rats. The RHA/Verh rats, however, failed to show any change in heart rate or immobility in response to a conditioned stress situation. The low dose of AVP (20 pg) in the CEA of conscious RLA/Verh rats caused an enhancement of the stress-induced bradycardiac and immobility response. However, the high dose of AVP (2 ng) and OXT (200 pg) attenuated the bradycardiac and immobility responses in the RLA/Verh rats. Infusion of AVP and OXT in the RHA/Verh rats failed to induce any change in heart rate nr immobility. Binding studies revealed that the AVP receptor selectively binds AVP with high affinity. In contrast, the OXT receptor recognizes both AVP and OXT with a similar (but lower) affinity. This suggests that the behavioral and autonomic responses of the high dose of AVP may be caused by OXT receptor stimulation. In conclusion, on the basis of the present results one may hypothesize that CEA differences in AVP and OXT innervation and/or receptor densities may contribute to the differences in coping strategy found in these animals.

Learning from Automation Surprises and "Going Sour" Accidents: Progress on Human-Centered Automation

Advances in technology and new levels of automation on commercial jet transports has had many effects. There have been positive effects from both an economic and a safety point of view. The technology changes on the flight deck also have had reverberating effects on many other aspects of the aviation system and different aspects of human performance. Operational experience, research investigations, incidents, and occasionally accidents have shown that new and sometimes surprising problems have arisen as well. What are these problems with cockpit automation, and what should we learn from them? Do they represent over-automation or human error? Or instead perhaps there is a third possibility - they represent coordination breakdowns between operators and the automation? Are the problems just a series of small independent glitches revealed by specific accidents or near misses? Do these glitches represent a few small areas where there are cracks to be patched in what is otherwise a record of outstanding designs and systems? Or do these problems provide us with evidence about deeper factors that we need to address if we are to maintain and improve aviation safety in a changing world? How do the reverberations of technology change on the flight deck provide insight into generic issues about developing human-centered technologies and systems (Winograd and Woods, 1997)? Based on a series of investigations of pilot interaction with cockpit automation (Sarter and Woods, 1992; 1994; 1995; 1997a, 1997 b), supplemented by surveys, operational experience and incident data from other studies (e.g., Degani et al., 1995; Eldredge et al., 1991; Tenney et al., 1995; Wiener, 1989), we too have found that the problems that surround crew interaction with automation are more than a series of individual glitches. These difficulties are symptoms that indicate deeper patterns and phenomena concerning human-machine cooperation and paths towards disaster. In addition, we find the same kinds of patterns behind results from studies of physician interaction with computer-based systems in critical care medicine (e.g., Moll van Charante et al., 1993; Obradovich and Woods, 1996; Cook and Woods, 1996). Many of the results and implications of this kind of research are synthesized and discussed in two comprehensive volumes, Billings (1996) and Woods et al. (1994). This paper summarizes the pattern that has emerged from our research, related research, incident reports, and accident investigations. It uses this new understanding of why problems arise to point to new investment strategies that can help us deal with the perceived "human error" problem, make automation more of a team player, and maintain and improve safety

Ergonomics and sustainability: Towards and embrace of complexity and emergence

Technology offers a promising route to a sustainable future, and ergonomics can serve a vital role. The argument of this article is that the lasting success of sustainability initiatives in ergonomics hinges on an examination of ergonomics' own epistemology and ethics. The epistemology of ergonomics is fundamentally empiricist and positivist. This places practical constraints on its ability to address important issues such as sustainability, emergence and complexity. The implicit ethical position of ergonomics is one of neutrality, and its positivist epistemology generally puts value-laden questions outside the parameters of what it sees as scientific practice. We argue, by contrast, that a discipline that deals with both technology and human beings cannot avoid engaging with questions of complexity and emergence and seeking innovative ways of addressing these issues.No Full Tex

Using Eye Tracking to Detect the Effects of Clutter on Visual Search in Real Time

Display clutter causes decrements in visual search performance and can be a threat to safety and efficiency in complex, data-rich domains. Addressing the problem requires a means to detect the presence of clutter in real time, predict its effects, and then trigger countermeasures before breakdowns in information search can occur. Eye tracking is a promising technique for achieving these goals; however, to date, it has been used almost exclusively offline for display evaluation purposes. The goal of this research was instead to develop and evaluate models that combine eye tracking metrics to detect the effects of clutter early on in the search process. Participants were asked to locate targets in a simulated graphics program. Three eye tracking metrics - scanpath length, mean saccade amplitude, and mean fixation duration - were calculated over a 3-second time window. These metrics were then used as input to a set of logistic regression models to predict whether users' response time will be relatively long or short. The accuracy of the models averaged 75% and the true positive rate was above 90%, with an ability to predict response time as early as 3.6 s into the visual search task. The results of this study confirm that eye tracking metrics can be used to predict the effects of display clutter in real time. They add to the knowledge base in attention and eye tracking, and they ultimately contribute to the design of adaptive displays that lead to improved operator performance. © 2013 IEEE

The effects of data density, display organization, and stress on search performance: An eye tracking study of clutter

Display clutter can cause breakdowns in visual search performance, which can compromise system safety and efficiency. The differential contributions of the two main aspects of clutter - data density and display organization - to these breakdowns are not well understood. Moreover, it is not clear how these factors interact with stress, another factor that can degrade performance in data-rich domains. The aim of this study was to ascertain the effects of data density, display organization, and stress on visual search performance and associated eye movements (obtained via eye tracking). To this end, participants performed visual search tasks in a simulated graphics program. Data density (number of icons), organization (grouping of icons), and stress (presence of a time limit) were manipulated. Response time (RT), error rate, eye tracking data, and subjective ratings of clutter and stress were collected. Results confirmed that high data density and poor organization increase RT and error rate. Furthermore, poor organization worsened the effects of high data density on RT. Stress did not negatively affect performance but significantly decreased RT. Eye tracking metrics provided insight into the effects of the two clutter aspects and stress. In particular, these metrics helped explain how changes in attention allocation resulted in the observed performance effects of long RT and high error rate. The results of this research can be used to inform the design of data-rich displays and trigger display adaptations in real time. © 2013 IEEE

In vivo functional neurochemistry of human cortical cholinergic function during visuospatial attention

Cortical acetylcholine is involved in key cognitive processes such as visuospatial attention. Dysfunction in the cholinergic system has been described in a number of neuropsychiatric disorders. Levels of brain acetylcholine can be pharmacologically manipulated, but it is not possible to directly measure it in vivo in humans. However, key parts of its biochemical cascade in neural tissue, such as choline, can be measured using magnetic resonance spectroscopy (MRS). There is evidence that levels of choline may be an indirect but proportional measure of acetylcholine availability in brain tissue. In this study, we measured relative choline levels in the parietal cortex using functional (event-related) MRS (fMRS) during performance of a visuospatial attention task, with a modelling approach verified using simulated data. We describe a task-driven interaction effect on choline concentration, specifically driven by contralateral attention shifts. Our results suggest that choline MRS has the potential to serve as a proxy of brain acetylcholine function in humans

Stress, epigenetic remodeling and FKBP51: Pathways to chronic pain vulnerability

Chronic pain and post-traumatic stress disorder (PTSD) show striking similarities in their prevalence following injury and trauma respectively, with growing evidence suggesting shared vulnerability mechanisms, particularly through stress-related epigenetic regulation. The gene FK506 binding protein 5, FKBP5, is a critical regulator of the stress response which plays a well-established role in PTSD susceptibility and has recently emerged as a potential driver of chronic pain vulnerability. In our pre-clinical study, sub-chronic stress promoted the persistence of subsequent inflammation-induced primary hyperalgesia and accelerated the development of inflammation-driven anxiety in male and female mice. Global deletion of Fkbp5 reduced stress-induced vulnerability to persistent pain, with a more pronounced protective effect in males than in females. To investigate the mechanisms underlying FKBP51-driven persistent pain vulnerability, we analysed male spinal cord tissue after stress exposure and found hypomethylation in the Fkbp5 promoter site for the canonical FKBP51 transcript and other stress-related genes. However, most epigenetic changes in key regulatory regions did not correlate with changes in gene expression, suggesting that stress exposure had remodelled the epigenome without altering gene activity. FKBP51 pharmacological inhibition in males during stress exposure shortened the duration of subsequent inflammatory pain and reversed several stress-induced DNA methylation changes in promoter regions of genes associated with stress and nociception, but not Fkbp5. These results indicate that sub-chronic stress increases the susceptibility to chronic pain in an FKBP51-driven mechanism and leads to the hypomethylation of Fkbp5. However, reversing Fkbp5 hypomethylation is not necessary to prevent chronic pain vulnerability, which is likely driven by complex epigenetic regulation

Monetary reward increases attentional effort in the flanker task

An important question is whether monetary reward can increase attentional effort in order to improve performance. Up to now, evidence for a positive answer is weak. Therefore, in the present study, the flanker task was used to examine this question further. Participants had to respond sooner than a certain deadline in a flanker task. One group of participants received a performance-contingent monetary reward, whereas the other group earned a fixed amount of money. As a result, monetary reward significantly improved performance in comparison with the control group. The analysis of speed accuracy trade-off functions revealed that monetary reward increased attentional effort, leading to an enhanced quality of stimulus coding. Little evidence was found that reward also improved selective spatial attention

Axonal Varicosity Density as an Index of Local Neuronal Interactions

Diffuse transmission is an important non-synaptic communication mode in the cerebral neocortex, in which neurotransmitters released from en passant varicosities interact with surrounding cells. In a previous study we have shown that the cholinergic axonal segments which were in the microproximity with dopaminergic fibers possessed a greater density of en passant varicosities compared to more distant segments, suggesting an activity-dependent level of en passant varicosities in the axonal zone of interaction. To further evaluate this plastic relationship, the density of cholinergic varicosities was quantified on fiber segments within the microproximity of activated or non-activated pyramidal cells of the prefrontal cortex (mPFC). Repetitive 14 days patterned visual stimulation paired with an electrical stimulation of the cholinergic fibers projecting to the mPFC from the HDB was performed to induce persistent axonal plastic changes. The c-Fos early gene immunoreactivity was used as a neuronal activity marker of layer V pyramidal cells, labelled with anti-glutamate transporter EAAC1. Cholinergic fibers were labeled with anti-ChAT (choline acetyltransferase) immunostaining. The density of ChAT+ varicosities on and the length of fiber segments within the 3 µm microproximity of c-Fos positive/negative pyramidal cells were evaluated on confocal images. More than 50% of the pyramidal cells in the mPFC were c-Fos immunoreactive. Density of ChAT+ varicosities was significantly increased within 3 µm vicinity of activated pyramidal cells (0.50±0.01 per µm of ChAT+ fiber length) compared to non-activated cells in this group (0.34±0.001; p≤0.05) or control rats (0.32±0.02; p≤0.05). Different types of stimulation (visual, HDB or visual/HDB) induced similar increase of the density of ChAT+ varicosities within microproximity of activated pyramidal cells. This study demonstrated at the subcellular level an activity-dependent enrichment of ChAT+ varicosities in the axonal zone of interaction with other neuronal elements