175 research outputs found
Neural correlates of processing valence and arousal in affective words
Psychological frameworks conceptualize emotion along 2 dimensions, "valence" and "arousal." Arousal invokes a single axis of intensity increasing from neutral to maximally arousing. Valence can be described variously as a bipolar continuum, as independent positive and negative dimensions, or as hedonic value (distance from neutral). In this study, we used functional magnetic resonance imaging to characterize neural activity correlating with arousal and with distinct models of valence during presentation of affective word stimuli. Our results extend observations in the chemosensory domain suggesting a double dissociation in which subregions of orbitofrontal cortex process valence, whereas amygdala preferentially processes arousal. In addition, our data support the physiological validity of descriptions of valence along independent axes or as absolute distance from neutral but fail to support the validity of descriptions of valence along a bipolar continuum
Differential interactions between identity and emotional expression in own and other-race faces: effects of familiarity revealed through redundancy gains.
We examined relations between the processing of facial identity and emotion in own- and other-race faces, using a fully crossed design with participants from 3 different ethnicities. The benefits of redundant identity and emotion signals were evaluated and formally tested in relation to models of independent and coactive feature processing and measures of processing capacity for the different types of stimuli. There was evidence for coactive processing of identity and emotion that was linked to super capacity for own-race but not for other-race faces. In addition, the size of the redundancy gain for other-race faces varied with the amount of social contact participants had with individuals from the other race. The data demonstrate qualitative differences in the processing of facial identity and emotion cues in own and other races. The results also demonstrate that the level of integration of identity and emotion cues in faces may be determined by life experience and exposure to individuals of different ethnicities
Integration of identity and emotion information in faces: fMRI evidence.
Separate neural systems have been implicated in the recognition of facial identity and emotional expression. A growing number of studies now provide evidence against this modular view by demonstrating that integration of identity and emotion information enhances face processing. Yet, the neural mechanisms that shape this integration remain largely unknown. We hypothesize that the presence of both personal and emotional expression target information triggers changes in functional connectivity between frontal and extrastriate areas in the brain. We report and discuss three important findings. First, the presence of target identity and emotional expression in the same face was associated with super capacity and violations of the independent processing of identity and expression cues. Second, activity in the orbitofrontal cortex (OFC) was associated with the presence of redundant targets and changes in functional connectivity between a particular region of the right OFC (BA11/47) and bilateral visual brain regions (the inferior occipital gyrus (IOG)). Third, these changes in connectivity showed a strong link to behavioural measures of capacity processing. We suggest that the changes in functional connectivity between the right OFC and IOG reduce variability of BOLD responses in the IOG, enhancing integration of identity and emotional expression cues in faces
Interactions between Identity and Emotional Expression in Face Processing across the Lifespan: Evidence from Redundancy Gains
We tested how aging affects the integration of visual information from faces. Three groups of participants aged 20-30, 40-50, and 60-70 performed a divided attention task in which they had to detect the presence of a target facial identity or a target facial expression. Three target stimuli were used: (1) with the target identity but not the target expression, (2) with the target expression but not the target identity, and (3) with both the target identity and target expression (the redundant target condition). On nontarget trials the faces contained neither the target identity nor expression. All groups were faster in responding to a face containing both the target identity and emotion compared to faces containing either single target. Furthermore the redundancy gains for combined targets exceeded performance limits predicted by the independent processing of facial identity and emotion. These results are held across the age range. The results suggest that there is interactive processing of facial identity and emotion which is independent of the effects of cognitive aging. Older participants demonstrated reliably larger size of the redundancy gains compared to the young group that reflect a greater experience with faces. Alternative explanations are discussed
Диагностика на основе многомерных нечетких отношений
Розглянуто відновлення причин (діагнозів) за спостережуваними наслідками (симптомами) на основі багатовимірних нечітких відношень і розширеного композиційного правила виведення. Проектування нечіткої системи діагностики полягає у розв’язанні нечітких логічних рівнянь сумісно з налаштуванням нечітких відношень на основі експертно-експериментальної інформації. Запропоновано метод розв’язання систем нечітких логічних рівнянь з розширеною max-min композицією. Доведено властивості множини розв’язків таких систем. Задачу знаходження множини розв’язків сформульовано у вигляді задачі оптимізації, для розв’язання якої використано генетико-нейронний підхід. Налаштування полягає у виборі таких функцій належності нечітких причин і наслідків, а також нечітких відношень, які мінімізують різницю між модельними і експериментальними результатами діагностики. Запропонований підхід проілюстровано комп’ютерним експериментом і прикладом технічної діагностики.This paper deals with restoration of the causes (diagnoses) through the observed effects (symptoms) on the basis of multivariable fuzzy relations and the extended compositional rule of inference. The design of a diagnostic fuzzy system consists of solving fuzzy relational equations together with tuning of fuzzy relations on the basis of information from experts and experiments. We propose a method for solving fuzzy relational equations with the extended max-min composition. We also prove the properties of the solution set for such systems. The problem of finding the solution set is formulated in the form of the optimization problem, which is solved using genetic algorithms and neural networks. The essence of tuning consists of the selection such membership functions for fuzzy causes and effects, and also fuzzy relations, which minimize the difference between model and experimental results of a diagnosis. The proposed approach is illustrated by the computer experiment and the example of a technical diagnosis.Рассмотрено восстановление причин (диагнозов) по наблюдаемым следствиям (симптомам) на основе многомерных нечетких отношений и расширенного композиционного правила выведения. Проектирование нечеткой системы диагностики состоит в решении нечетких логических уравнений совместно с настройкой нечетких отношений на основе экспертно-экспериментальной информации. Предложен метод решения систем нечетких логических уравнений с расширенной max-min композицией. Доказаны свойства множества решений таких систем. Задача нахождения множества решений сформулирована в виде задачи оптимизации, для решения которой используется генетико-нейронный подход. Настройка состоит в выборе таких функций принадлежности нечетких причин и следствий, а также нечетких отношений, которые минимизируют отличие между модельными и экспериментальными результатами диагностики. Предложенный подход проиллюстрирован компьютерным экспериментом и примером технической диагностики
Моделювання та оптимізація надійності багатовимірних алгоритмічних процесів
В монографії досліджується моделювання та оптимізація надійності багатовимірних алгоритмічних процесів, при виконанні яких вносяться, виявляються та усуваються помилки різних типів. Пропонуються постановки та методи розв’язання задач чіткої та нечіткої оптимізації надійності таких процесів. Узагальнено багатовимірні моделі надійності операторів, логічних умов та типових алгоритмічних структур на випадок нечітких даних.
Монографія буде корисною проектувальникам, науковим співробітникам, аспірантам та студентам старших курсів технічних університетів, які займаються моделюванням та забезпеченням надійності складних систем
Recovery after stroke: not so proportional after all?
The proportional recovery rule asserts that most stroke survivors recover a fixed proportion of lost function. To the extent that this is true, recovery from stroke can be predicted accurately from baseline measures of acute post-stroke impairment alone. Reports that baseline scores explain more than 80%, and sometimes more than 90%, of the variance in the patients’ recoveries, are rapidly accumulating. Here, we show that these headline effect sizes are likely inflated. The key effects in this literature are typically expressed as, or reducible to, correlation coefficients between baseline scores and recovery (outcome scores minus baseline scores). Using formal analyses and simulations, we show that these correlations will be extreme when outcomes are significantly less variable than baselines, which they often will be in practice regardless of the real relationship between outcomes and baselines. We show that these effect sizes are likely to be over-optimistic in every empirical study that we found that reported enough information for us to make the judgement, and argue that the same is likely to be true in other studies as well. The implication is that recovery after stroke may not be as proportional as recent studies suggest
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Investigation of the possibility of using continuous electron beams for electromotive liner hardening. Final report (Task 3)
Continuous laser and electron beams are presently used for surface hardening of steel and cast iron articles. The main advantage of the sources of continuous electron beams over lasers is their high (over 90%) efficiency of conversion of an electric energy to the energy of an electron beam. A promising version of electron-beam system is that including a plasma electron source of the type developed at the Institute of High Current Electronics (IHCE, Tomsk). This type of source has a long lifetime and can operate at a poor vacuum ({approximately} 10{sup {minus}2} torr) in the working chamber. Owing to this they are successfully used for electron-beam welding, melting-on of hardening coatings, and surface hardening of machine parts. The goal of the present work is to elucidate whether it is possible to use a plasma-cathode continuous electron gun for hardening the internal surface of cast iron liners
Interactions between metabolic, reward and cognitive processes in appetite control:Implications for novel weight management therapies
Traditional models of appetite control have emphasised the role of parallel homeostatic and hedonic systems, but more recently the distinction between independent homeostatic and hedonic systems has been abandoned in favour of a framework that emphasises the cross talk between the neurochemical substrates of the two systems. In addition, evidence has emerged more recently, that higher level cognitive functions such as learning, memory and attention play an important role in everyday appetite control and that homeostatic signals also play a role in cognition. Here, we review this evidence and present a comprehensive model of the control of appetite that integrates cognitive, homeostatic and reward mechanisms. We discuss the implications of this model for understanding the factors that may contribute to disordered patterns of eating and suggest opportunities for developing more effective treatment approaches for eating disorders and weight management
Dynamics of trimming the content of face representations for categorization in the brain
To understand visual cognition, it is imperative to determine when, how and with what information the human brain categorizes the visual input. Visual categorization consistently involves at least an early and a late stage: the occipito-temporal N170 event related potential related to stimulus encoding and the parietal P300 involved in perceptual decisions. Here we sought to understand how the brain globally transforms its representations of face categories from their early encoding to the later decision stage over the 400 ms time window encompassing the N170 and P300 brain events. We applied classification image techniques to the behavioral and electroencephalographic data of three observers who categorized seven facial expressions of emotion and report two main findings: (1) Over the 400 ms time course, processing of facial features initially spreads bilaterally across the left and right occipito-temporal regions to dynamically converge onto the centro-parietal region; (2) Concurrently, information processing gradually shifts from encoding common face features across all spatial scales (e.g. the eyes) to representing only the finer scales of the diagnostic features that are richer in useful information for behavior (e.g. the wide opened eyes in 'fear'; the detailed mouth in 'happy'). Our findings suggest that the brain refines its diagnostic representations of visual categories over the first 400 ms of processing by trimming a thorough encoding of features over the N170, to leave only the detailed information important for perceptual decisions over the P300
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