Right-lateralised lane keeping in young and older British drivers

Young adults demonstrate a small, but consistent, asymmetry of spatial attention favouring the left side of space (“pseudoneglect”) in laboratory-based tests of perception. Conversely, in more naturalistic environments, behavioural errors towards the right side of space are often observed. In the older population, spatial attention asymmetries are generally diminished, or even reversed to favour the right side of space, but much of this evidence has been gained from lab-based and/or psychophysical testing. In this study we assessed whether spatial biases can be elicited during a simulated driving task, and secondly whether these biases also shift with age, in line with standard lab-based measures. Data from 77 right-handed adults with full UK driving licences (i.e. prior experience of left-lane driving) were analysed: 38 young (mean age = 21.53) and 39 older adults (mean age = 70.38). Each participant undertook 3 tests of visuospatial attention: the landmark task, line bisection task, and a simulated lane-keeping task. We found leftward biases in young adults for the landmark and line bisection tasks, indicative of pseudoneglect, and a mean lane position towards the right of centre. In young adults the leftward landmark task biases were negatively correlated with rightward lane-keeping biases, hinting that a common property of the spatial attention networks may have influenced both tasks. As predicted, older adults showed no group-level spatial asymmetry on the landmark nor the line bisection task, but they maintained a mean rightward lane position, similar to young adults. The 3 tasks were not inter-correlated in the older group. These results suggest that spatial biases in older adults may be elicited more effectively in experiments involving complex behaviour rather than abstract, lab-based measures. More broadly, these results confirm that lateral biases of spatial attention are linked to driving behaviour, and this could prove informative in the development of future vehicle safety and driving technology

A study of visuomotor behaviour in normal and brain lesioned human subjects, with special reference to line bisection performance in patients with hemispatial neglect

In Experiments 1 to 8 an attempt was made to examine the nature of the displacements found in the traditional line bisection test when applied to normal (right-handed), as well as brain lesioned subjects. The problem with this test is that it invariably confounds perceptual and motor components which might both contribute to the observed errors. However, use of the 'landmark task' enables an examination of perceptual effects in isolation. It was found that five out of six neglect patients judged the left half-line of a centrally bisected line as shorter than the right half-line. Moreover, it was consistently shown that cueing strongly influenced judgements in normal and left and right hemisphere lesioned subjects (without neglect) in that it caused them to overestimate the cued part of the line. It was argued that the perception of relative size is subject to systematic distortion as a function of this selective attention within the visual field. Neglect patients may present an abnormal example of this attentionally- induced illusion in that their attentional resources may be abnormally biased towards the ipsilesional space. The result of this imbalance may be to cause, quite directly, a gross abnormality of size perception. Nonetheless one of the neglect patients did not show spatial misperception but spatially misdirected actions, in line with what has been described as directional hypokinesia. Experiments 9 to 12 were designed to demonstrate any possible contribution the right hemisphere might make to visuomotor control, but the data on normal subjects gave little indication of a specific right hemisphere involvement in such tasks. Neither use of a spatial bisection task, nor absence of visual feedback of the moving hand or arm seemed to produce left hand advantages on the dependent measures. On the other hand, RCVA patients proved to be impaired in their reaching behaviour in that they erred systematically to the right of the true target over all three spatial positions, in the absence of visual feedback. The bias was interpreted as a pure example of directional hypokinesia

Intra- and inter-task reliability of spatial attention measures in healthy older adults

At present, there is a lack of systematic investigation into intra- and inter-task consistency effects in older adults, when investigating lateralised spatial attention. In young adults, spatial attention typically manifests itself in a processing advantage for the left side of space (“pseudoneglect”), whereas older adults have been reported to display no strongly lateralised bias, or a preference towards the right side. Building on our earlier study in young adults, we investigated older adults, aged between 60 to 86 years, on five commonly used spatial attention tasks (line bisection, landmark, grey and grating scales and lateralised visual detection). Results confirmed a stable test-retest reliability for each of the five spatial tasks across two testing days. However, contrary to our expectations of a consistent lack in bias or a rightward bias, two tasks elicited significant left spatial biases in our sample of older participants, in accordance with pseudoneglect (namely the line bisection and greyscales tasks), while the other three tasks (landmark, grating scales, and lateralised visual detection tasks) showed no significant biases to either side of space. This lack of inter-task correlations replicates recent findings in young adults. Comparing the two age groups revealed that only the landmark task was age sensitive, with a leftward bias in young adults and an eliminated bias in older adults. In view of these findings of no significant inter-task correlations, as well as the inconsistent directions of the observed spatial biases for the older adults across the five tested tasks, we argue that pseudoneglect is a multi-component phenomenon and highly task sensitive. Each task may engage slightly distinct neural mechanisms, likely to be impacted differently by age. This complicates generalisation and comparability of pseudoneglect effects across different tasks, age-groups and hence studies

Low pre-stimulus EEG alpha power amplifies visual awareness but not visual sensitivity

Pre‐stimulus oscillatory neural activity has been linked to the level of awareness of sensory stimuli. More specifically, the power of low frequency oscillations (primarily in the alpha‐band, i.e. 8‐14 Hz) prior to stimulus‐onset is inversely related to measures of subjective performance in visual tasks, such as confidence and visual awareness. Intriguingly, the same EEG‐signature does not seem to influence objective measures of task performance (i.e. accuracy). We here examined whether this dissociation holds when stringent accuracy measures are used. Previous EEG‐studies have employed 2‐alternative forced‐choice (2‐AFC) discrimination tasks to link pre‐stimulus oscillatory activity to correct/incorrect responses as an index of accuracy/objective performance at the single‐trial level. However, 2‐AFC tasks do not provide a good estimate of single‐trial accuracy, as many of the responses classified as correct will be contaminated by guesses (with the chance correct response rate being 50%). Here instead, we employed a 19‐AFC letter identification task to measure accuracy and the subjectively reported level of perceptual awareness on each trial. As the correct guess rate is negligible (~5%), this task provides a purer measure of accuracy. Our results replicate the inverse relationship between pre‐stimulus alpha/beta‐band power and perceptual awareness ratings in the absence of a link to discrimination accuracy. Pre‐stimulus oscillatory phase did not predict either subjective awareness or accuracy. Our results hence confirm a dissociation of the pre‐stimulus EEG power ‐ task performance link for subjective versus objective measures of performance, and further substantiate pre‐stimulus alpha power as a neural predictor of visual awareness

Correction: Intra- and inter-task reliability of spatial attention measures in pseudoneglect

No abstract available

Long term improvements in activities of daily living in patients with hemispatial neglect

No abstract available

Both dorsal and ventral attention network nodes are implicated in exogenously driven visuospatial anticipation

Neuroimaging and transcranial magnetic stimulation (TMS) studies have implicated a dorsal fronto-parietal network in endogenous attention control and a more ventral set of areas in exogenous attention shifts. However, the extent and circumstances under which these cortical networks overlap and/or interact remain unclear. Crucially, whereas previous studies employed experimental designs that tend to confound exogenous with endogenous attentional engagement, we used a cued target discrimination paradigm that behaviourally dissociates exogenous from endogenous attention processes. Participants engaged with endogenous attention cues, while simultaneous apparent motion cues were driving exogenous attention along the motion path towards or away from the target position. To interfere with dorsal or ventral attention networks, we delivered neuronavigated double-pulse TMS over either right intraparietal sulcus (rIPS) or right temporo-parietal junction (rTPJ) towards the end of the cue target interval, and compared the effects to a sham-TMS condition. For sham-TMS, endogenous and exogenous cueing both benefitted discrimination accuracy. Target discrimination was enhanced at validly versus invalidly cued locations (endogenous cueing benefit) as well as when targets appeared in versus out of the motion path (exogenous cueing benefit), despite motion being uninformative and task-irrelevant, replicating previous findings. Interestingly, both rIPS- and rTPJ-TMS abolished attention benefits from exogenous cueing, while endogenous cueing benefits were unaffected. Our findings provide evidence against independent involvement of the dorsal and ventral attention network nodes in exogenous attention processes

Trial-by-trial co-variation of pre-stimulus EEG alpha power and visuospatial bias reflects a mixture of stochastic and deterministic effects

Human perception of perithreshold stimuli critically depends on oscillatory EEG activity prior to stimulus onset. However, it remains unclear exactly which aspects of perception are shaped by this pre‐stimulus activity and what role stochastic (trial‐by‐trial) variability plays in driving these relationships. We employed a novel jackknife approach to link single‐trial variability in oscillatory activity to psychometric measures from a task that requires judgement of the relative length of two line segments (the landmark task). The results provide evidence that pre‐stimulus alpha fluctuations influence perceptual bias. Importantly, a mediation analysis showed that this relationship is partially driven by long‐term (deterministic) alpha changes over time, highlighting the need to account for sources of trial‐by‐trial variability when interpreting EEG predictors of perception. These results provide fundamental insight into the nature of the effects of ongoing oscillatory activity on perception. The jackknife approach we implemented may serve to identify and investigate neural signatures of perceptual relevance in more detail

Impacts of Improved Animal Welfare Standards on Competitiveness of EU Animal Production

The paper presents results of the FP7 Econ-Welfare Project “Assessing the socio-economic consequences of measures promoting good animal welfare”. The paper illustrates the economic consequences at the farm level of indicative improvements in animal welfare conditions for pigs and cattle and addresses the consequences of improved animal welfare for international trade and competitiveness1. For the farm level considerations costs - effectiveness analysis was applied, whilst impacts of the upgraded standards on international trade and competitiveness was assessed with the use of the partial equilibrium Agmemod model. The Belief Network Approach was used to determine the effects of animal welfare standards and labels on the competitiveness of the EU animal production and supply chain.Introducing upgraded Animal Welfare standards at the farm level would increase costs of production in pigs and beef cattle sectors. In dairy sector upgrading cows welfare standards results with higher benefits than costs. Accordingly, Agmemod results indicate that on the pork and beef markets international competitive position of the EU producers may be undermined. However, as the analysis showed, there are both supply conditions and demand side circumstances which may well resolve the apparent conflict between animal welfare and chain competitiveness. On the supply side, it is apparent that there are some animal welfare improvements that can be made without compromising competitiveness. Supply chain information, education and training may well be able to improve both animal welfare and competitiveness. In addition, better understanding of both animal welfare and animal productivity (through R&D) can be expected to lead to improvements in both objectives

An investigation into discomfort and fatigue related to the wearing of an EEG neurofeedback headset

Self-regulating brain activity using electroencephalography (EEG) neurofeedback has the potential to improve cognitive functions, rehabilitate motor control and reduce chronic fatigue. Nonetheless, user experience and factors which may interfere with the beneficial effects of neurofeedback are still under researched. This preliminary study aimed to investigate whether wearing an EEG neurofeedback recommended headset for 1 hour induced significant physical discomfort and fatigue. Data were obtained from a standard visual analogue scale questionnaire and a newly developed EEG headset discomfort (EEGhd) questionnaire. 21 participants (12 in the experimental (headset) and 9 in the control (electrodes only) group) watched a nature documentary video while their brain signals were recorded. They completed the set of questionnaires before and after the video, while wearing the EEG headset (or electrodes). A two-sample t-test revealed that the experimental group experienced significantly higher EEGhd than the controls (p < .001). Participants reported the onset of discomfort after approximately 25 minutes. These results highlight the importance of assessing user experience and accounting for physical discomfort when designing an EEG neurofeedback study