Expert tool users show increased differentiation between visual representations of hands and tools

The idea that when we use a tool we incorporate it into the neural representation of our body (embodiment) has been a major inspiration for philosophy, science and engineering. While theoretically appealing, there is little direct evidence for tool embodiment at the neural level. Using functional magnetic resonance imaging (fMRI) in male and female human subjects, we investigated whether expert tool users (London litter pickers: n=7) represent their expert tool more like a hand (neural embodiment) or less like a hand (neural differentiation), as compared to a group of tool novices (n=12). During fMRI scans, participants viewed first-person videos depicting grasps performed by either a hand, litter picker or a non-expert grasping tool. Using representational similarity analysis, differences in the representational structure of hands and tools were measured within occipitotemporal (OTC). Contrary to the neural embodiment theory, we find that the experts group represent their own tool less like a hand (not more) relative to novices. Using a case-study approach, we further replicated this effect, independently, in 5 of the 7 individual expert litter pickers, as compared to the novices. An exploratory analysis in left parietal cortex, a region implicated in visuomotor representations of hands and tools, also indicated that experts do not visually represent their tool more similar to hands, compared to novices. Together, our findings suggest that extensive tool use leads to an increased neural differentiation between visual representations of hands and tools. This evidence provides an important alternative framework to the prominent tool embodiment theory

Methods and Apparatus for Determining a Path in a Communication Network

United States Patent Filing No:United States Patent Filing No:United States Patent Filing No:Typically paths are provisioned in a network with a margin which allows for component variations and failures in the network and so on. By providing more information about the requirements of the link in a path request, it is possible to more efficiently calculate a route for the path through the network. The efficiency gain allows greater network utilization which in turn saves costs for the network service provider

The categories, frequencies, and stability of idiosyncratic eye-movement patterns to faces

The spatial pattern of eye-movements to faces considered typical for neurologically healthy individuals is a roughly T-shaped distribution over the internal facial features with peak fixation density tending toward the left eye (observer's perspective). However, recent studies indicate that striking deviations from this classic pattern are common within the population and are highly stable over time. The classic pattern actually reflects the average of these various idiosyncratic eye-movement patterns across individuals. The natural categories and respective frequencies of different types of idiosyncratic eye-movement patterns have not been specifically investigated before, so here we analyzed the spatial patterns of eye-movements for 48 participants to estimate the frequency of different kinds of individual eye-movement patterns to faces in the normal healthy population. Four natural clusters were discovered such that approximately 25% of our participants' fixation density peaks clustered over the left eye region (observer's perspective), 23% over the right eye-region, 31% over the nasion/bridge region of the nose, and 20% over the region spanning the nose, philthrum, and upper lips. We did not find any relationship between particular idiosyncratic eye-movement patterns and recognition performance. Individuals' eye-movement patterns early in a trial were more stereotyped than later ones and idiosyncratic fixation patterns evolved with time into a trial. Finally, while face inversion strongly modulated eye-movement patterns, individual patterns did not become less distinct for inverted compared to upright faces. Group-averaged fixation patterns do not represent individual patterns well, so exploration of such individual patterns is of value for future studies of visual cognition

Start position strongly influences fixation patterns during face processing: Difficulties with eye movements as a measure of information use.

Fixation patterns are thought to reflect cognitive processing and, thus, index the most informative stimulus features for task performance. During face recognition, initial fixations to the center of the nose have been taken to indicate this location is optimal for information extraction. However, the use of fixations as a marker for information use rests on the assumption that fixation patterns are predominantly determined by stimulus and task, despite the fact that fixations are also influenced by visuo-motor factors. Here, we tested the effect of starting position on fixation patterns during a face recognition task with upright and inverted faces. While we observed differences in fixations between upright and inverted faces, likely reflecting differences in cognitive processing, there was also a strong effect of start position. Over the first five saccades, fixation patterns across start positions were only coarsely similar, with most fixations around the eyes. Importantly, however, the precise fixation pattern was highly dependent on start position with a strong tendency toward facial features furthest from the start position. For example, the often-reported tendency toward the left over right eye was reversed for the left starting position. Further, delayed initial saccades for central versus peripheral start positions suggest greater information processing prior to the initial saccade, highlighting the experimental bias introduced by the commonly used center start position. Finally, the precise effect of face inversion on fixation patterns was also dependent on start position. These results demonstrate the importance of a non-stimulus, non-task factor in determining fixation patterns. The patterns observed likely reflect a complex combination of visuo-motor effects and simple sampling strategies as well as cognitive factors. These different factors are very difficult to tease apart and therefore great caution must be applied when interpreting absolute fixation locations as indicative of information use, particularly at a fine spatial scale

Ready Exerciser One: Effects of Music and Virtual Reality on Cycle Ergometer Exercise

© 2020 The Authors. Objectives Physical inactivity remains a major global health concern, and researchers have been encouraged to explore the role of technology in the promotion of physical activity. Technologies that deliver audio‐visual stimuli are frequently applied in the exercise domain. However, there is a paucity of research that examines the efficacy of modern virtual reality (VR) technology in this context. We investigated the effects of VR and music on affective, perceptual, enjoyment, and cardiac responses to aerobic‐type exercise. Design A fully counterbalanced, within‐subjects design was employed. Methods A convenience sample of recreationally active adult volunteers (N = 24) completed a 12‐min protocol during which they exercised under music, VR, VR‐with‐music, and control conditions. Results Analyses indicated a Condition × Time interaction for affective valence and perceived activation. Moreover, a main effect of condition emerged for state attention and perceived enjoyment. The VR and VR‐with‐music conditions elicited the most positive affective valence, highest levels of perceived activation, greatest number of dissociative thoughts, and most exercise enjoyment. Differences between these two conditions were negligible across the breadth of dependent variables. Conclusions The present findings illustrate the efficacy of modern VR technology in the exercise context, applied both with and without musical accompaniment. Additional research is required to assess the degree to which the findings are replicable among sedentary or ageing segments of the population. Given the emerging support pertaining to a positive relationship between affective responses and exercise adherence, VR technology should be considered as a means by which to promote an enjoyable exercise experience

Plasticity of the human visual system after retinal gene therapy in patients with Leber's congenital amaurosis.

Much of our knowledge of the mechanisms underlying plasticity in the visual cortex in response to visual impairment, vision restoration, and environmental interactions comes from animal studies. We evaluated human brain plasticity in a group of patients with Leber's congenital amaurosis (LCA), who regained vision through gene therapy. Using non-invasive multimodal neuroimaging methods, we demonstrated that reversing blindness with gene therapy promoted long-term structural plasticity in the visual pathways emanating from the treated retina of LCA patients. The data revealed improvements and normalization along the visual fibers corresponding to the site of retinal injection of the gene therapy vector carrying the therapeutic gene in the treated eye compared to the visual pathway for the untreated eye of LCA patients. After gene therapy, the primary visual pathways (for example, geniculostriate fibers) in the treated retina were similar to those of sighted control subjects, whereas the primary visual pathways of the untreated retina continued to deteriorate. Our results suggest that visual experience, enhanced by gene therapy, may be responsible for the reorganization and maturation of synaptic connectivity in the visual pathways of the treated eye in LCA patients. The interactions between the eye and the brain enabled improved and sustained long-term visual function in patients with LCA after gene therapy

Synthesis and characterisation of controllably functionalised polyaniline nanofibres

A novel method for functionalising solution based polyaniline (PAni) nanofibres is reported whereby the degree of side-chain attachment can be controllably altered. The covalent attachment of functional side-groups to the surface of PAni nanostructures is achieved by post-polymerisation reflux in the presence of a nucleophile and the functionalised nanomaterial can be purified by simple centrifugation. The technique is therefore easily scalable. We demonstrate that control over the extent of side-chain attachment can be achieved simply by altering the amount of nucleophile added during reflux. We provide evidence that covalently attached carboxlate side-chains influence the doping mechanism of polyaniline and can be used to introduce self-doping behaviour. Acid functionalised nanofibres remain redox active and retain their optical switching capabilities in response to changes in the local chemical environment, thus making them suitable for adaptive sensing applications

Fructose transport-deficient Staphylococcus aureus reveals important role of epithelial glucose transporters in limiting sugar-driven bacterial growth in airway surface liquid.

Hyperglycaemia as a result of diabetes mellitus or acute illness is associated with increased susceptibility to respiratory infection with Staphylococcus aureus. Hyperglycaemia increases the concentration of glucose in airway surface liquid (ASL) and promotes the growth of S. aureus in vitro and in vivo. Whether elevation of other sugars in the blood, such as fructose, also results in increased concentrations in ASL is unknown and whether sugars in ASL are directly utilised by S. aureus for growth has not been investigated. We obtained mutant S. aureus JE2 strains with transposon disrupted sugar transport genes. NE768(fruA) exhibited restricted growth in 10 mM fructose. In H441 airway epithelial-bacterial co-culture, elevation of basolateral sugar concentration (5-20 mM) increased the apical growth of JE2. However, sugar-induced growth of NE768(fruA) was significantly less when basolateral fructose rather than glucose was elevated. This is the first experimental evidence to show that S. aureus directly utilises sugars present in the ASL for growth. Interestingly, JE2 growth was promoted less by glucose than fructose. Net transepithelial flux of D-glucose was lower than D-fructose. However, uptake of D-glucose was higher than D-fructose across both apical and basolateral membranes consistent with the presence of GLUT1/10 in the airway epithelium. Therefore, we propose that the preferential uptake of glucose (compared to fructose) limits its accumulation in ASL. Pre-treatment with metformin increased transepithelial resistance and reduced the sugar-dependent growth of S. aureus. Thus, epithelial paracellular permeability and glucose transport mechanisms are vital to maintain low glucose concentration in ASL and limit bacterial nutrient sources as a defence against infection

Arsenic hyperaccumulation by different fern species

Pteris vittata was the first identified arsenic (As) hyperaccumulator. Our aim was to test whether As hyperaccumulation occurs in other fern species, and whether P. vittata collected from both contaminated and uncontaminated environments accumulates As similarly. Three accessions of P. vittata, two cultivars of Pteris cretica, Pteris longifoliaandPteris umbrosa were grown with 0-500 mg As kg(-1) added to the substrate. A second experiment compared As uptake by five common ferns obtained from commercial suppliers. The results show that, in addition to P. vittata, P. cretica, P. longifolia and P. umbrosa also hyperaccumulate As to a similar extent. There was little difference between different Pteris species, or between different accessions of P. vittata. By contrast, Asplenium nidus , Davallia canarensis, Polypodium aureum, Polystichum tsus-simense do not hyperaccumulate As. This study identified three new species of As hyperaccumulators in the Pteris genus and suggests that As hyperaccumulation is a constitutive property in P. vittata

Visual responsiveness in sensorimotor cortex is increased following amputation and reduced after mirror therapy

Phantom limb pain (PLP) following amputation, which is experienced by the vast majority of amputees, has been reported to be relieved with daily sessions of mirror therapy. During each session, a mirror is used to view the reflected image of the intact limb moving, providing visual feedback consistent with the movement of the missing/phantom limb. To investigate potential neural correlates of the treatment effect, we measured brain responses in volunteers with unilateral leg amputation using functional magnetic resonance imaging (fMRI) during a four-week course of mirror therapy. Mirror therapy commenced immediately following baseline scans, which were repeated after approximately two and four week intervals. We focused on responses in the region of sensorimotor cortex corresponding to primary somatosensory and motor representations of the missing leg. At baseline, prior to starting therapy, we found a strong and unexpected response in sensorimotor cortex of amputees to visually presented images of limbs. This response was stronger for images of feet compared to hands and there was no such response in matched controls. Further, this response to visually presented limbs was no longer present at the end of the four week mirror therapy treatment, when perceived phantom limb pain was also reduced. A similar pattern of results was also observed in extrastriate and parietal regions typically responsive to viewing hand actions, but not in regions corresponding to secondary somatosensory cortex. Finally, there was a significant correlation between initial visual responsiveness in sensorimotor cortex and reduction in PLP suggesting a potential marker for predicting efficacy of mirror therapy. Thus, enhanced visual responsiveness in sensorimotor cortex is associated with PLP and modulated over the course of mirror therapy