3,029 research outputs found

    The life project

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    This conference paper is available to download from the publisher’s website at the link below.The Life Project explores issues of psychological projection into technology by diving into the convoluted relationship between practical purpose and emotional attachment, through both the creative act of designing and making robot entities with artificial emotions, and the social act of engaging with them. This process explores the concept of body representation through a multiidentity in virtual and physical blended space. In a lesser sense, it also suggests a future world of collaboration between physical and virtual forms, enabled by new forms of representation in blended worlds

    Preconditioning of low-frequency repetitive transcranial magnetic stimulation with transcranial direct current stimulation: evidence for homeostatic plasticity in the human motor cortex

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    Recent experimental work in animals has emphasized the importance of homeostatic plasticity as a means of stabilizing the properties of neuronal circuits. Here, we report a phenomenon that indicates a homeostatic pattern of cortical plasticity in healthy human subjects. The experiments combined two techniques that can produce long-term effects on the excitability of corticospinal output neurons: transcranial direct current stimulation (TDCS) and repetitive transcranial magnetic stimulation (rTMS) of the left primary motor cortex. "Facilitatory preconditioning" with anodal TDCS caused a subsequent period of 1 Hz rTMS to reduce corticospinal excitability to below baseline levels for >20 min. Conversely, "inhibitory preconditioning" with cathodal TDCS resulted in 1 Hz rTMS increasing corticospinal excitability for at least 20 min. No changes in excitability occurred when 1 Hz rTMS was preceded by sham TDCS. Thus, changing the initial state of the motor cortex by a period of DC polarization reversed the conditioning effects of 1 Hz rTMS. These preconditioning effects of TDCS suggest the existence of a homeostatic mechanism in the human motor cortex that stabilizes corticospinal excitability within a physiologically useful range

    Weissistachys Kentuckiensis: A new Name for Weissia Kentuckiense Rothwell and Taylor

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    This is the publisher's version, also available electronically from www.jstor.org.The generic name Weissia Roth well and Taylor is determined to be a later homonym of Weissia Hedwig. Weissia Rothwell and Taylor is therefore renamed Weissistachys, and the appropriate name transfer is made for the type species, Weissistachys kentuckiensis (Rothwell et Taylor) comb. nov

    Studies of Paleozoic Calamitean Cones: Weissia Kentuckiense Gen. et Sp. Nov.

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    This is the publisher's version, also available electronically from http://www.jstor.org.The recent discovery of a new petrified fructification from the Lewis Creek coal ball locality in eastern Kentucky adds to our knowledge of the structure and diversity of c alamitean cones. The incomplete specimen measures 4.8 cm long and 6.0 mm in diameter, and is composed of alternating bract and sporangiophore whorls. Approximately 24 bracts are present in each whorl. Bracts arise at right angles to the axis and are fused into a shallow disk for 2.0 mm before arching distally and becoming free. Six sporangiophores arise obliquely from slightly above each bract disk; each sporangiophore bears two large pendant sporangia that are attached along their distal and tangential surfaces. Sporangia! walls are a single cell layer thick and are characterized by internal cell lumen partitions. The distal ends of the sporangiophores are fused to form a continuous ring of tissue that surrounds the sporangia. Features of the new cone are discussed in relation to those of other calamitean cones of similar age

    Proprioception in motor learning: : lessons from a deafferented subject

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    This document is the Accepted Manuscript version of the following article: N. Yousif, J. Cole, J. Rothwell, and J. Diedrichsen, ‘Proprioception in motor learning: lessons from a deafferented subject’, Experimental Brain Research, Vol. 233 (8): 2449-2459, August 2015. The final publication is available at Springer via https://doi.org/10.1007/s00221-015-4315-8.Proprioceptive information arises from a variety of channels, including muscle, tendon, and skin afferents. It tells us where our static limbs are in space and how they are moving. It remains unclear however, how these proprioceptive modes contribute to motor learning. Here, we studied a subject (IW) who has lost large myelinated fibres below the neck and found that he was strongly impaired in sensing the static position of his upper limbs, when passively moved to an unseen location. When making reaching movements however, his ability to discriminate in which direction the trajectory had been diverted was unimpaired. This dissociation allowed us to test the involvement of static and dynamic proprioception in motor learning. We found that IW showed a preserved ability to adapt to force fields when visual feedback was present. He was even sensitive to the exact form of the force perturbation, responding appropriately to a velocity- or position-dependent force after a single perturbation. The ability to adapt to force fields was also preserved when visual feedback about the lateral perturbation of the hand was withdrawn. In this experiment, however, he did not exhibit a form of use-dependent learning, which was evident in the control participants as a drift of the intended direction of the reaching movement in the perturbed direction. This suggests that this form of learning may depend on static position sense at the end of the movement. Our results indicate that dynamic and static proprioception play dissociable roles in motor learning.Peer reviewedFinal Accepted Versio

    Proprioception in motor learning: : lessons from a deafferented subject

    Get PDF
    This document is the Accepted Manuscript version of the following article: N. Yousif, J. Cole, J. Rothwell, and J. Diedrichsen, ‘Proprioception in motor learning: lessons from a deafferented subject’, Experimental Brain Research, Vol. 233 (8): 2449-2459, August 2015. The final publication is available at Springer via https://doi.org/10.1007/s00221-015-4315-8.Proprioceptive information arises from a variety of channels, including muscle, tendon, and skin afferents. It tells us where our static limbs are in space and how they are moving. It remains unclear however, how these proprioceptive modes contribute to motor learning. Here, we studied a subject (IW) who has lost large myelinated fibres below the neck and found that he was strongly impaired in sensing the static position of his upper limbs, when passively moved to an unseen location. When making reaching movements however, his ability to discriminate in which direction the trajectory had been diverted was unimpaired. This dissociation allowed us to test the involvement of static and dynamic proprioception in motor learning. We found that IW showed a preserved ability to adapt to force fields when visual feedback was present. He was even sensitive to the exact form of the force perturbation, responding appropriately to a velocity- or position-dependent force after a single perturbation. The ability to adapt to force fields was also preserved when visual feedback about the lateral perturbation of the hand was withdrawn. In this experiment, however, he did not exhibit a form of use-dependent learning, which was evident in the control participants as a drift of the intended direction of the reaching movement in the perturbed direction. This suggests that this form of learning may depend on static position sense at the end of the movement. Our results indicate that dynamic and static proprioception play dissociable roles in motor learning.Peer reviewedFinal Accepted Versio

    Air pollution biomonitoring in an urban-industrial setting (Taranto, Italy) using Mediterranean plant species

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    This study presents the first report on the elemental composition of five Mediterranean plant species (Pinus pinaster, Eucalyptus camaldulensis, Nerium oleander, Olea europaea and Pittosporum heterophyllum) to trace industrial emissions in Taranto, Italy, a mixed-use industrial and urban setting. Potential metal sources include vehicular traffic, steel and cement plants, and a petrochemical refinery. Samples were collected from 29 sites covering the Tamburi-Lido Azzurro neighbourhood and the historical quarter Città Vecchia-Borgo. High concentrations of toxic metals were observed in all samples, with marked inter-species variability. Model based clustering identified two distinct groups, one dominated by pine needles with higher metal concentrations than the other group composed of the other four plant species. The contamination factor (CF) and pollution load index (PLI) indices which use background samples to standardise the level of pollution, were used to remove species effect allowing for direct site comparison. Spatial analysis of CF and PLI data identified pollution hotspots near industrial areas and major roads, with areas of little to no air pollution near green spaces. Statistical analysis of the CFs revealed the contribution of different sources to element emissions. Ni and Cr were primarily emitted from the steel plant and petrochemical refinery, while Fe and Al were associated with road traffic emissions, and geogenic elements Ca, Mg, K, and Na were linked to marine spray and Saharan dust. This study demonstrates that combining multiple plant species with pollution indices can be a cost-effective biomonitoring approach for assessing air pollution and creating a high-density spatial monitoring network

    Assessing TMS-induced D and I waves with spinal H-reflexes

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    Transcranial magnetic stimulation (TMS) of motor cortex produces a series of descending volleys known as D (direct) and I (indirect) waves. In the present study, we questioned whether spinal H-reflexes can be used to dissect D waves and early and late I waves from TMS. We therefore probed H-reflex facilitation at arrival times of D and I waves at the spinal level and thereby changed TMS parameters that have previously been shown to have selective effects on evoked D and different I waves. We changed TMS intensity and current direction and applied a double-pulse paradigm known as short-interval intracortical inhibition (SICI). Experiments were conducted in flexor carpi radialis (FCR) in the arm and soleus (SOL) in the leg. There were two major findings: 1) in FCR, H-reflex facilitation showed characteristic modulations with altered TMS parameters that correspond to the changes of evoked D and I waves; and 2) H-reflexes in SOL did not, possibly because of increased interference from other spinal circuits. Therefore, the most significant outcome of this study is that in FCR, H-reflexes combined with TMS seem to be a useful technique to dissect TMS-induced D and I waves. NEW & NOTEWORTHY Questions that relate to corticospinal function in pathophysiology and movement control demand sophisticated techniques to provide information about corticospinal mechanisms. We introduce a noninvasive electrophysiological technique that may be useful in describing such mechanisms in more detail by dissecting D and I waves from transcranial magnetic stimulation (TMS). Based on the combination of spinal H-reflexes and TMS in the flexor carpi radialis muscle, the technique was shown to measure selective effects on D and I waves from changing TMS parameters
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