1,720,966 research outputs found
Functional and anatomical networks of executive control
Full text linkActions are selected in the context of environmental demands and internal goals. Both change constantly and dynamically and several studies have addressed the issue of how information about these is represented, updated and integrated in the brain to form appropriate decisions and actions. The reprogramming of actions requires inhibition of movements or movement plans, resolution of response conflict and initiation of alternative actions. The right inferior frontal cortex (rIFC) and the presupplementary motor areas (pre-SMA) have been suggested to play a major role in response inhibition and action reprogramming. The degree to which inhibition of actions at a behavioural level can be related to physiological inhibition is unknown.Using single and paired-pulse transcranial magnetic stimulation (TMS), we investigated M1 excitability and M1 internal inhibitory mechanisms during action reprogramming (see Chapter 2.1.1). The temporal pattern of M1 excitability and M1 internal inhibitory mechanisms differed from those during normal action execution and could therefore play a causal role in action reprogramming. These findings are important as M1 is likely to be the site of convergence from different influences exerted by regions in the frontal lobes.In a second experiment we used paired-pulse TMS over rIFC and M1 to investigate functional rIFC-M1 interactions (see 2.1.2). We found that rIFC inhibited M1 excitability 175 ms after cue onset only in trials when actions needed to be reprogrammed and responses had to be inhibited, but not during normal action selection.In a third experiment we used a combined paired-pulse TMS – diffusion tensor imaging (DTI) approach to elucidate anatomical pathways of functional pre-SMA-M1 and rIFC-M1 connectivity (see 2.2). We found extended networks of executive control and action reprogramming. These results suggest that both, pre-SMA and rIFC influence motor output via premotor areas and fronto-basal ganglia loops. Different latency periods of rIFC-M1 and pre-SMA-M1 interactions were mediated by different white matter paths and networks.In a fourth experiment we tried to delineate the roles of rIFC and pre-SMA during action reprogramming using a combined paired-pulse TMS– repetitive TMS paradigm (see 2.3). The inhibitory influence exerted by rIFC over M1 during action reprogramming disappeared after mild and transient disruption of pre-SMA activity.Besides elucidating a network of brain areas associated with action reprogramming and movement inhibition these experiments have interesting methodological implications
Functional and anatomical networks of executive control
No full textActions are selected in the context of environmental demands and internal goals. Both
change constantly and dynamically and several studies have addressed the issue of
how information about these is represented, updated and integrated in the brain to
form appropriate decisions and actions. The reprogramming of actions requires
inhibition of movements or movement plans, resolution of response conflict and
initiation of alternative actions. The right inferior frontal cortex (rIFC) and the presupplementary
motor areas (pre-SMA) have been suggested to play a major role in
response inhibition and action reprogramming. The degree to which inhibition of
actions at a behavioural level can be related to physiological inhibition is unknown.Using single and paired-pulse transcranial magnetic stimulation (TMS), we
investigated M1 excitability and M1 internal inhibitory mechanisms during action
reprogramming (see Chapter 2.1.1). The temporal pattern of M1 excitability and M1
internal inhibitory mechanisms differed from those during normal action execution
and could therefore play a causal role in action reprogramming. These findings are
important as M1 is likely to be the site of convergence from different influences
exerted by regions in the frontal lobes.In a second experiment we used paired-pulse TMS over rIFC and M1 to investigate
functional rIFC-M1 interactions (see 2.1.2). We found that rIFC inhibited M1
excitability 175 ms after cue onset only in trials when actions needed to be
reprogrammed and responses had to be inhibited, but not during normal action
selection.In a third experiment we used a combined paired-pulse TMS – diffusion tensor
imaging (DTI) approach to elucidate anatomical pathways of functional pre-SMA-M1
and rIFC-M1 connectivity (see 2.2). We found extended networks of executive
control and action reprogramming. These results suggest that both, pre-SMA and rIFC
influence motor output via premotor areas and fronto-basal ganglia loops. Different
latency periods of rIFC-M1 and pre-SMA-M1 interactions were mediated by different
white matter paths and networks.In a fourth experiment we tried to delineate the roles of rIFC and pre-SMA during
action reprogramming using a combined paired-pulse TMS– repetitive TMS paradigm
(see 2.3). The inhibitory influence exerted by rIFC over M1 during action
reprogramming disappeared after mild and transient disruption of pre-SMA activity.Besides elucidating a network of brain areas associated with action reprogramming
and movement inhibition these experiments have interesting methodological
implications.This thesis is not currently available via ORA
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
Ventral prefrontal cortex structure and function in behavioural change
Full text linkThere is a considerable interest in the neural correlates of cognitive flexibility, language, valuation, credit assignment and decision-making. The ventrolateral, orbital and medial prefrontal cortex together with their long-range connections with the rest of the brain are thought to be critically involved in these cognitive processes. My thesis explores human and monkey ventrolateral, orbital and medial prefrontal cortex and their potential role in flexible adaptation and choice. In the introductory chapter I review neuroeconomic and neuro-ecological views of decision making, as well as modular versus connectionist views of brain structure and function. In the second and third chapter I investigate the connectivity of ventrolateral, orbital and medial prefrontal cortex and compare their sub-regions between humans and monkeys. Overall I report a striking degree of similarity of connectivity profiles across species even though these regions are thought to support uniquely human cognitive abilities such as language, social cognition, prospective planning and strategic decision-making. This may be taken to suggest that higher order cognitive functions “re-use” a neural apparatus that is shared with macaque monkeys. In the fourth chapter I present a parcellation of the white matter into the major long-range association fibre systems based on their projection patterns to the cortical surface. These findings may have implications not only for the cross-species comparison of connectivity-profiles but also for understanding some psychiatric and neurological disorders as "disconnection syndromes". I conclude by evaluating whether a modular view of brain structure and function is consistent with a view that portraits the brain as changeable, highly adaptive and strongly interconnected
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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