scholarly journals Linking signal detection theory and encoding models to reveal independent neural representations from neuroimaging data

2018 ◽  
Author(s):  
Fabian A. Soto ◽  
Lauren E. Vucovich ◽  
F. G. Ashby

AbstractMany research questions in visual perception involve determining whether stimulus properties are represented and processed independently. In visual neuroscience, there is great interest in determining whether important object dimensions are represented independently in the brain. For example, theories of face recognition have proposed either completely or partially independent processing of identity and emotional expression. Unfortunately, most previous research has only vaguely defined what is meant by “independence,” which hinders its precise quantification and testing. This article develops a new quantitative framework that links signal detection theory from psychophysics and encoding models from computational neuroscience, focusing on a special form of independence defined in the psychophysics literature: perceptual separability. The new theory allowed us, for the first time, to precisely define separability of neural representations and to theoretically link behavioral and brain measures of separability. The framework formally specifies the relation between these different levels of perceptual and brain representation, providing the tools for a truly integrative research approach. In particular, the theory identifies exactly what valid inferences can be made about independent encoding of stimulus dimensions from the results of multivariate analyses of neuroimaging data and psychophysical studies. In addition, commonly used operational tests of independence are re-interpreted within this new theoretical framework, providing insights on their correct use and interpretation. Finally, we apply this new framework to the study of separability of brain representations of face identity and emotional expression (neutral/sad) in a human fMRI study with male and female participants.Author SummaryA common question in vision research is whether certain stimulus properties, like face identity and expression, are represented and processed independently. We develop a theoretical framework that allowed us, for the first time, to link behavioral and brain measures of independence. Unlike previous approaches, our framework formally specifies the relation between these different levels of perceptual and brain representation, providing the tools for a truly integrative research approach in the study of independence. This allows to identify what kind of inferences can be made about brain representations from multivariate analyses of neuroimaging data or psychophysical studies. We apply this framework to the study of independent processing of face identity and expression.

2021 ◽  
Vol 13 (6) ◽  
pp. 3278
Author(s):  
Renée De Reuver ◽  
Brigitte Kroon ◽  
Damian Madinabeitia Olabarria ◽  
Unai Elorza Iñurritegui

In contrast to shareholder-owned organizations, worker-owned cooperative organizations foster employee wellbeing such as employee satisfaction as an important outcome by itself. Due to expansions and economic fluctuations, larger worker-owned cooperations nowadays use mixtures of employment contracts resulting in varying shares of co-owners, contracted and temporary employees in workplaces. In the current paper, we research if this situation challenges the moral commitment of worker cooperatives to their employees, which derive from the cooperative philosophy on corporate responsibility. Where previous research contrasted employee wellbeing in worker cooperatives with share- holder owner organizations, this paper describes how various shares of co-owners in workplaces change mediating processes of helping climate and workplace participation and ultimately result in different levels of employee satisfaction. Archival data combined with survey data of 5907 employees in 99 hypermarkets were tested with multivariate analyses, and indicated that the helping climate and workplace participation positively mediated the association between the share of co-owners in hypermarkets and employee satisfaction. The findings imply that traditional worker-owned cooperatives, where a majority of all workers are owners, had more success in fostering cooperative values as a strategic outcome.


2020 ◽  
Vol 30 (1) ◽  
pp. 138-150
Author(s):  
Veronika Valková ◽  
Hana Ďúranová ◽  
Jana Štefániková ◽  
Michal Miškeje ◽  
Marián Tokár ◽  
...  

AbstractThe current study was designed to enhance the functionality of white bread by replacement of wheat flour with different levels (1%, 2%, 5%, and 8%) of grape seeds micropowder (GSMP) with nanosized particles (10 µm). Chemical composition of GSMP, volume and sensory attributes, evaluated with the panel of evaluators and an electronic nose (e-nose) and an electronic eye (e-eye) were investigated in the tested breads. It has been found out that GSMP contained appreciable amounts of flavonoids including catechin, epicatechin, gallic acid and minerals especially, Ca, K and Mg. The data from rheological analysis showed that the addition of GSMP (mainly at 5% and 8% levels) to the wheat flour had a positive effect on dough manifesting with rheology by increased dough stability. The volume of the experimental breads (above 1% concentration) was demonstrably declined (P < 0.0001) in comparison with the control bread. Sensory rating revealed that the bread fortified with 1% GSMP was judged by the consumer panelists as the most acceptable with the highest scores for all quality attributes which was also confirmed by the data of e-nose and e-eye. Our results suggest for the first time that 1% GSMP addition appears to be a promising functional ingredient to improve bread with required qualitative and sensory properties.


2015 ◽  
Vol 742 ◽  
pp. 330-334
Author(s):  
Chun Jian Wang ◽  
Wei Yue ◽  
Hai Yan Ji

In allusion to the need of analyzing complex system, we have proposed a method named multi-grade color Petri net. We for the first time use this new method to analyze a missile training simulator system. This model can accurately reflect the complex environments of the system and avoid the difficulty occurring often in developing accurate mathematics model by using classical research approach.


2021 ◽  
pp. 1-14
Author(s):  
Álvaro Clua Uceda

On 11 October 1935, the inauguration of the Slussen urban cloverleaf took place in front of the excited citizens of Stockholm. It had the attributes of a pure traffic machine taken from the most advanced traffic engineering publications, and it expressed the optimistic cultural modernism that five years ago the Stockholm International Exhibition had promoted.1 This urban cloverleaf was made of translucent glass, reinforced concrete, metallic handrails, and reflective tiles and was meant to solve, in one single gesture, the complex urban link between the Lake Mälaren and the Baltic Sea, between Gamla Stan – the historic city centre – and Södermalm – the southern district built on top of the 35-metre-high plateau [1]. The solution made difficult urban compromises between the foothills of the Brunkeberg topography, the smooth water surfaces of the Stockholm archipelago, the architecture of the historic urban tissue, and the demands of a complex articulated mobility. Boats, goods, suburban trains, subways, trams – later buses – pedestrians, cyclists, and automobiles finally converged on this place at different levels, completing the intricacies of a threedimensional geometry which, for the first time in history, was inserted into a compact city.


1998 ◽  
Vol 353 (1377) ◽  
pp. 1801-1818 ◽  
Author(s):  
◽  
N. K. Logothetis

Figures that can be seen in more than one way are invaluable tools for the study of the neural basis of visual awareness, because such stimuli permit the dissociation of the neural responses that underlie what we perceive at any given time from those forming the sensory representation of a visual pattern. To study the former type of responses, monkeys were subjected to binocular rivalry, and the response of neurons in a number of different visual areas was studied while the animals reported their alternating percepts by pulling levers. Perception–related modulations of neural activity were found to occur to different extents in different cortical visual areas. The cells that were affected by suppression were almost exclusively binocular, and their proportion was found to increase in the higher processing stages of the visual system. The strongest correlations between neural activity and perception were observed in the visual areas of the temporal lobe. A strikingly large number of neurons in the early visual areas remained active during the perceptual suppression of the stimulus, a finding suggesting that conscious visual perception might be mediated by only a subset of the cells exhibiting stimulus selective responses. These physiological findings, together with a number of recent psychophysical studies, offer a new explanation of the phenomenon of binocular rivalry. Indeed, rivalry has long been considered to be closely linked with binocular fusion and stereopsis, and the sequences of dominance and suppression have been viewed as the result of competition between the two monocular channels. The physiological data presented here are incompatible with this interpretation. Rather than reflecting interocular competition, the rivalry is most probably between the two different central neural representations generated by the dichoptically presented stimuli. The mechanisms of rivalry are probably the same as, or very similar to, those underlying multistable perception in general, and further physiological studies might reveal a much about the neural mechanisms of our perceptual organization.


Author(s):  
Е.И. КОБАХИДЗЕ

В статье впервые анализируются раннесоветские практики формирования финансово-бюджетной сферы Северной Осетии в контексте государственной политики управления финансами. Их изучение представляется актуальным в связи с очевидным параллелизмом с процессами первого постсоветского десятилетия, когда в России формировалось новое политическое и экономическое пространство, в котором были активно задействованы восстановительные хозяйственно-экономические механизмы, применявшиеся в 20-х гг. XX в. Становление финансовой и бюджетной системы в Северной Осетии рассматривается в ее тесной связи с ходом государственного строительства; отдельное внимание уделено вопросам налогообложения, формирования бюджетов разных уровней, конкретным показателям хозяйственно-экономического развития Осетии на разных этапах переходного периода и в рамках политико-экономических стратегий «военного коммунизма» и «новой экономической политики». Общая специфика исследуемых процессов обусловлена значительными политическими трансформациями, переживаемыми страной в ходе построения советского государства и социалистической экономики. В то же время анализ документов и материалов, в том числе впервые вводимых в научный оборот, показывает, что Осетия, оказавшись в советской системе власти и управления, приобрела собственный опыт построения основ государственности и ее институтов, в том числе в финансовой сфере. For the first time, the article analyzes the early Soviet practices of the formation of the financial and budgetary sphere of North Ossetia in the context of the state policy of financial management. Their study is relevant in connection with the obvious parallelism with the processes of the first post-Soviet decade, when a new political and economic space was formed in Russia, in which the restorative economic mechanisms used in the 1920s were actively involved. The formation of the financial and budgetary system in North Ossetia is considered in its close connection with the progress of state building; special attention is paid to the issues of taxation, the formation of budgets of different levels, specific indicators of economic development of Ossetia at different stages of the transition period and within the framework of political and economic strategies of “war communism” and “new economic policy”. The general specificity of the processes under study is due to the significant political transformations experienced by the country in the course of building the Soviet state and socialist economy. At the same time, the analysis of documents and materials, including those introduced into scientific circulation for the first time, shows that Ossetia, having found itself in the Soviet system of power and administration, has acquired its own experience in building the foundations of statehood and its institutions, in the financial sphere as well.


2018 ◽  
Vol 120 (6) ◽  
pp. 2761-2774 ◽  
Author(s):  
Michaela Bruton ◽  
Nicholas O’Dwyer

At face value, the term “synergy” provides a unifying concept within a fractured field that encompasses complementary neural, computational, and behavioral approaches. However, the term is not used synonymously by different researchers but has substantially different meanings depending on the research approach. With so many operational definitions for the one term, it becomes difficult to use as either a descriptive or explanatory concept, yet it remains pervasive and apparently indispensable. Here we provide a summary of different approaches that invoke synergies in a descriptive or explanatory context, summarizing progress, not within the one approach, but across the theoretical landscape. Bernstein’s framework of flexible hierarchical control may provide a unifying framework here, since it can incorporate divergent ideas about synergies. In the current motor control literature, synergy may refer to conceptually different processes that could potentially operate in parallel, across different levels within the same hierarchical control scheme. There is evidence for the concurrent existence of synergies with different features, both “hard-wired” and “soft-wired,” and task independent and task dependent. By providing a comprehensive overview of the multifaceted ideas about synergies, our goal is to move away from the compartmentalization and narrow the focus on one level and promote a broader perspective on the control and coordination of movement.


Author(s):  
Ekaterina S. Romanova

The issue of the interrelation of social representations of students with different levels of suggestibility about a socially profitable person is discussed. The content of the concept of a “socially profitable person” is revealed. The analysis of theoretical and methodological literature concretizes the content of the concepts of “social representations”, “suggestibility”. In the study we take into account the gender characteristics of the subjects. The obtained results have a scientific novelty, since this kind of work was carried out for the first time. It was found that the sample has mainly an average suggestibility level, is malleable and tends to allow other people’s ideas into their consciousness. Semantic units (descriptors) describing the ideas of a socially profitable person in boys and girls do not have significant differences. Factors were formed from the obtained descriptors: 12 – in boys, 13 – in girls, 11 factors coincided. The dominant factors were “Social and material well-being”, “Benevolence”, “Cultural and cognitive factor”. The practical significance of the study is in the possibility of organizing purposeful work on the formation of a positive image of a person in demand by society. Representations determine the assessment of one’s own qualities, regulate human behavior. Further development of the problem can be aimed at expanding the sample of subjects and creating a psychological and pedagogical program.


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