102,288 research outputs found
Haptic working memory for grasping: the role of the parietal operculum
No full textWe investigated how haptic information on object geometry is encoded in the parietal operculum (OP) and is used for guiding object-directed motor acts in humans. We tested the effects of conditioning single-pulse transcranial magnetic stimulation (spTMS) applied to the left OP on corticospinal excitability assessed by a test spTMS applied to the ipsilateral motor cortex (M1) 5 ms after conditioning spTMS. Participants explored the size of a graspable object visually or haptically and waited for a go-signal to grasp it in the dark. They received TMS during the delay phase. In a separate group of participants performing the same task, conditioning spTMS was applied to the ventral premotor cortex (vPM) 7 ms before test spTMS. Results showed that conditioning TMS over OP modulated M1 output according to the information on object size that had been acquired haptically but not visually. Vice versa, conditioning TMS over vPM modulated M1 output according to information on object size acquired by vision but not haptically. Moreover spTMS over OP produced a significant modulation of the upcoming reaching behavior only when the object had been explored haptically. We show that OP contains a haptic memory of objects' macrogeometry and the appropriate motor plan for grasping them
Towards Rabies Elimination in Belgium by Fox Vaccination Using a Vaccinia-Rabies Glycoprotein Recombinant Virus
No full textpeer reviewedOral immunization of foxes by distributing vaccine baits was experimentally assessed and subsequently employed in the whole of the infected area of Belgium (10,000 km2). A vaccinia-rabies glycoprotein recombinant virus (VR-G) was used as vaccine because of its efficacy, safety and heat stability. Five 'full' campaigns of fox vaccination, carried out from 1989 until 1991, induced a drastic decrease in the incidence of rabies. The disease has disappeared from the major part of the initial infected area. In 1992 and 1993, three 'defence' campaigns, carried out along international borders, completely eliminated rabies virus infection from the fox population in 1993
Online repetitive transcranial magnetic stimulation (TMS) to the parietal operculum disrupts haptic memory for grasping
No full textThe parietal operculum (OP) contains haptic memory on the geometry of objects that is readily transferrable to the motor cortex but a causal role of OP in memory-guided grasping is only speculative. We explored this issue by using online high-frequency repetitive transcranial magnetic stimulation (rTMS). The experimental task was performed by blindfolded participants acting on objects of variable size. Trials consisted in three phases: haptic exploration of an object, delay, and reach-grasp movement onto the explored object. Motor performance was evaluated by the kinematics of finger aperture. Online rTMS was applied to the left OP region separately in each of the three phases of the task. The results showed that rTMS altered grip aperture only when applied in the delay phase to the OP. In a second experiment a haptic discriminative (match-to-sample) task was carried out on objects similar to those used in the first experiment. Online rTMS was applied to the left OP. No psychophysical effects were induced by rTMS on the detection of explicit haptic object size. We conclude that neural activity in the OP region is necessary for proficient memory-guided haptic grasping. The function of OP seems to be critical while maintaining the haptic memory trace and less so while encoding it or retrieving it
Bibliographie Hilarion G. Petzold 1958 – 2009 mit Anhang als Einführung
No full textDieses Archiv enthält die Gesamtbibliographie der Werke des Autors nebst einiger Texte „Über H. G. Petzold“ im Schlussteil der Bibliographie sowie einen Anhang mit einer Einführung in die Architektur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author and some texts about H. G. Petzold, moreover an epilogue with an introduction to the architecture of the works in its epistemological structure and composition and as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2009-petzold-h-g-gesamtbibliographie-h-g-petzold-1958-2009-updating-november2009/peerReviewedpublishedVersio
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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3346: Samuel G. Freedman, author, 2013
No full textPhotograph of author Samuel G. Freedman, at NT Daily Slash meeting in the Mayborn School of Journalism at UNT
Coleoptera (VII). News about colombian Sphaenognathus pubescens lucanidae (Warterhouse), s. bordoni (Brochier & Chalumeau); s. bellicosus (Boileau) and s. nobilis colombiensis (Moxey) (coleopterous: lucanidae).
No full textEl presente trabajo tiene el propósito de conocer la actual situación de los Lucánidos Sphaenognathus pubescens (Waterhouse), S. bordoni (Brochier & Chalumeau), S. bellicosus (Boileau) y S. nobilis colombiensis (Moxey) en Colombia, mediante reporte de material depositado en colecciones nacionales, datos de localidades y uso que dan algunas etnias a estos insectos en su alimentación habitual.The purpose of this work is to recognize the present situation of Lucanidae Sphaenognathus pubescens (Waterhouse), S. bordoni (Brochier & Chalumeau), S. bellicosus (Boileau) and S. nobilis colombiensis (Moxey) in Colombia by means of the report of material placed in national collections, data from some locations, and the use given to these insects by some ethnic groups in their regular diet
Modulation of primary motor cortex outputs from ventral premotor cortex during visually guided grasp in the macaque monkey
No full textArea F5, in the ventral premotor cortex of the macaque monkey, plays a critical role in determining the hand shape appropriate for grasp of a visible object. F5 neurones show increased firing for particular types of grasp, and inactivation of F5 produces deficits in visually guided grasp. But how is F5 activity transformed into the appropriate pattern of hand muscle activity for efficient grasp? Here we investigate the pathways that may be involved by testing the effect of single stimuli delivered through microwires chronically implanted in area F5 and in primary motor cortex (M1) of two macaque monkeys. The EMG responses from M1 test (T) stimulation were recorded from 4-11 contralateral hand, digit and arm muscles during reach-to-grasp of visually presented objects. Conditioning (C) stimulation of F5, at intensities subthreshold for motor effects, caused strong modulation (over twofold) of M1 test (T) responses. The pattern of facilitation was specific. First, facilitation of the T response was particularly evident at short C-T intervals of -1 to 1 ms. Second, this facilitation was only present in some muscles and during reach-to-grasp of a subset of objects; it did not appear to be simply related to the level of EMG activity in the muscles at the moment of cortical stimulation or indeed to the upcoming contribution of that muscle during grasp. At later C-T intervals (1-6 ms), F5 stimulation caused significant suppression of the test M1 response. The results are in keeping with the concept that during visually guided grasp, F5 modulates corticospinal outputs from M1 in a muscle- and grasp-specific manner
A cortico-cortical mechanism mediating object-driven grasp in humans.
No full textHumans and other primates demonstrate an exquisite ability to precisely shape their hand when reaching out to grasp an object. Here we used a recently developed transcranial magnetic stimulation paradigm to examine how information about an object's geometric properties is transformed into specific motor programs. Pairs of transcranial magnetic stimulation pulses were delivered at precise intervals to detect changes in the excitability of cortico-cortical inputs to motor cortex when subjects prepared to grasp different objects. We show that at least 600 ms before movement, there is an enhancement in the excitability of these inputs to the corticospinal neurons projecting from motor cortex to the specific muscles that will be used for the grasp. These changes were object-and muscle-specific, and the degree of modulation in the inputs was correlated with the pattern of muscular activity used later by individual subjects to grasp the objects. In a number of control experiments, we demonstrated that no change in excitability was observed during object presentation alone, under conditions in which subjects imagined grasping the object, or before movements involving the same muscles but without an object. This finding demonstrates a cortico-cortical mechanism subserving the transformation from the geometrical properties of an object to the outputs from motor cortex before grasp that is specific for object-driven movements
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