1,720,970 research outputs found
Interaction-Mediated Tool Use Differently Enhances Physical and Social Cognition in Macaques (Macaca fascicularis)
Full text linkIn primates, learning to use a tool modulates cognitive functions related to the physical properties of objects. However, the impact of tool-use learning on social aspects of cognition has not been explored. We addressed this question via a training paradigm by using six, adult, long-tailed macaques (Macaca fascicularis), who were born in captivity and housed in the animal facility of the Department of Neuroscience and Rehabilitation of the University of Ferrara, Italy. We tested the effects of interaction-mediated tool use on overall cognitive performance in an experimental group (n = 2 males and n = 1 females). To evaluate changes in cognitive performance, we applied the Primate Cognition Test Battery at different stages of the training procedure that involved an interaction between the animal and an experimenter and the macaque using a rake to retrieve food items. As a control, we evaluated the performance of an age- and sex-matched group performing an interactive, manual grasping task. Several parameters related to the recognition of the position and noise of specific objects (i.e., space and causality in physical cognition), and those related to image-object association and object pointing to draw the attention of experimenter (i.e., communication aspects of social cognition) showed a significant improvement in the interaction-mediated tool-use group after the training period. The effects were transient, but the enhancement related to the noise and object pointing persisted for 35 days without further training. The control group showed no changes in cognitive performance. Our results show that interaction-mediated tool use enhances cognitive performance in both physical and social cognition domains
Long and short whiskers differently guide snout/pellet interaction in rat oral grasping
No full textWe studied the role of rat whisker/snout tactile sense during oral grasping, comparing control data with those obtained, respectively, 1-3 and 5-7 days after bilateral long or short whisker trimming and 3-5 and 8-10 days after bilateral infraorbital nerve (ION) severing. Two behavioural phases were identified: whisker-snout contact by nose-N or lip-L and snout-tongue contact. The second phase involved either: snout passing over stationary pellet (Still pellet); pellet rolling as the snout passed over it (Rolling pellet); pellet being pushed forward by the snout (Pushed pellet); or pellet being hit and pushed away (Hit/Lost pellet). In controls, success was 100%, with N-contact prevailing over L-contact in the first phase and Still pellet in the second. In long whisker-trimmed versus controls, success was still 100%, but L-contact increased in frequency, Pushed pellet prevailed and the second phase duration increased. In short whisker-trimmed versus controls, success remained 100%, with increased L-contact frequency; the first phase duration did not change, but the second phase increased since in pushed trials, the pellet rolled around the snout. In ION-severed versus controls, both phases changed drastically: L-contact frequency increased, Pushed pellet prevailed and contact was persistently maintained; Hit/Lost pellet emerged, Still and Rolling pellets disappeared and the oral-grasping sequence was not triggered. These results suggest that long and short whiskers, respectively, optimize the first and second phases of snout-pellet interaction and that whisker/snout sense is necessary to trigger oral grasping. Kinematic trajectory analysis supports the conclusion that movement from whisker to snout contact is an orientation response
L-DOPA promotes striatal dopamine release through D1 receptors and reversal of dopamine transporter
No full textPrevious studies have pointed out that L-DOPA can interact with D1 or D2 receptors independent of its conversion to endogenous dopamine. The present study was set to investigate whether L-DOPA modulates dopamine release from striatal nerve terminals, using a preparation of synaptosomes preloaded with [3H]DA. Levodopa (1 μM) doubled the K+-induced [3H]DA release whereas the D2/D3 receptor agonist pramipexole (100 nM) inhibited it. The L-DOPA-evoked facilitation was mimicked by the D1 receptor agonist SKF38393 (30–300 nM) and prevented by the D1/D5 antagonist SCH23390 (100 nM) but not the DA transporter inhibitor GBR12783 (300 nM) or the aromatic L-amino acid decarboxylase inhibitor benserazide (1 μM). Higher L-DOPA concentrations (10 and 100 μM) elevated spontaneous [3H]DA efflux. This effect was counteracted by GBR12783 but not SCH23390. Binding of [3H]SCH23390 in synaptosomes (in test tubes) revealed a dense population of D1 receptors (2105 fmol/mg protein). Both SCH23390 and SKF38393 fully inhibited [3H]SCH23390 binding (Ki 0.42 nM and 29 nM, respectively). L-DOPA displaced [3H]SCH23390 binding maximally by 44% at 1 mM. This effect was halved by addition of GBR12935 and benserazide. We conclude that L-DOPA facilitates exocytotic [3H]DA release through SCH23390-sensitive D1 receptors, independent of its conversion to DA. It also promotes non-exocytotic [3H]DA release, possibly via conversion to DA and reversal of DA transporter. These data confirm that L-DOPA can directly interact with dopamine D1 receptors and might extend our knowledge of the neurobiological mechanisms underlying L-DOPA clinical effects
Cerebellar Modulation of Cortically Evoked Complex Movements in Rats
No full textIntracortical microstimulation (ICMS) delivered to the motor cortex (M1) via long-or short-train duration (long-or shortduration ICMS) can evoke coordinated complex movements or muscle twitches, respectively. The role of subcortical cerebellar input in M1output, in terms of long- A nd short-duration ICMS-evokedmovement and motor skill performance,was evaluated in rats with bilateral lesion of the deep cerebellar nuclei. After the lesion, distal forelimb movements were seldom observed, and almost 30% of proximal forelimb movements failed to match criteria defining the movement class observed under control conditions. The classifiablemovements could be evoked in different cortical regions with respect to control and manykinematic variableswere strongly affected. Furthermore,movement endpoints within the rat's workspace shrunk closer to the body, while performance in the reaching/grasping task worsened. Surprisingly, neither the threshold current values for evokingmovements nor the overall size of forelimb movement representation changed with respect to controls in either long-or short-duration ICMS.We therefore conclude that cerebellar input via the motor thalamus is crucial for expressing the basic functional features of the motor cortex
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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