scholarly journals Dynamic arousal signals construct memories of time and events

2019 ◽  
Author(s):  
David Clewett ◽  
Camille Gasser ◽  
Lila Davachi

AbstractEveryday life unfolds continuously, yet we tend to remember past experiences as discrete event sequences or episodes. Although this phenomenon has been well documented, the brain mechanisms that support the transformation of continuous experience into memorable episodes remain unknown. Here we show that a sudden change in context, or ‘event boundary’, elicits a burst of autonomic arousal, as indexed by pupil dilation. These boundaries during dynamic experience also led to the segmentation of adjacent episodes in later memory, evidenced by changes in memory for the timing, order, and perceptual details of recent event sequences. Critically, we find that distinct cognitive components of this pupil response were associated with both subjective (temporal distance judgements) and objective (temporal order discrimination) measures of episodic memory, suggesting that multiple arousal-mediated cognitive processes help construct meaningful mnemonic events. Together, these findings reveal that arousal processes may play a fundamental role in everyday memory organization.

2021 ◽  
Author(s):  
Hugh McGovern ◽  
Marte Otten

Bayesian processing has become a popular framework by which to understand cognitive processes. However, relatively little has been done to understand how Bayesian processing in the brain can be applied to understanding intergroup cognition. We assess how categorization and evaluation processes unfold based on priors about the ethnic outgroup being perceived. We then consider how the precision of prior knowledge about groups differentially influence perception depending on how the information about that group was learned affects the way in which it is recalled. Finally, we evaluate the mechanisms of how humans learn information about other ethnic groups and assess how the method of learning influences future intergroup perception. We suggest that a predictive processing framework for assessing prejudice could help accounting for seemingly disparate findings on intergroup bias from social neuroscience, social psychology, and evolutionary psychology. Such an integration has important implications for future research on prejudice at the interpersonal, intergroup, and societal levels.


2018 ◽  
Author(s):  
Barbara Dworetzky ◽  
Jong Woo Lee

Epilepsy is a chronic disorder of the brain characterized by recurrent unprovoked seizures. A seizure is a sudden change in behavior that is accompanied by electrical discharges in the brain. Many patients presenting with a first-ever seizure are surprised to find that it is a very common event. A reversible or avoidable seizure precipitant, such as alcohol, argues against underlying epilepsy and therefore against treatment with medication. This chapter discusses the epidemiology, etiology, and classification of epilepsy and provides detailed descriptions of neonatal syndromes, syndromes of infancy and early childhood, and syndromes of late childhood and adolescence. The pathophysiology, diagnosis, and differential diagnosis are described, as are syncope, migraine, and psychogenic nonepileptic seizures. Two case histories are provided, as are sections on treatment (polytherapy, brand-name versus generic drugs, surgery, stimulation therapy, dietary treatments), complications of epilepsy and related disorders, prognosis, and quality measures. Special topics discussed are women?s issues and the elderly. Figures illustrate a left midtemporal epileptic discharge, wave activity during drowsiness, cortical dysplasias, convulsive syncope, rhythmic theta activity, right hippocamal sclerosis, and right temporal hypometabolism. Tables describe international classifications of epileptic seizures and of epilepsies, epilepsy syndromes and related seizure disorders, differential diagnosis of seizure, differentiating epileptic versus nonepileptic seizures, antiepileptic drugs, status epilepticus protocol for treatment, when to consider referral to a specialist, and quality measures in epilepsy.  This review contains 7 figures, 10 tables, and 33 references. Key Words: Seizures, focal (partial)seizure, generalized seizures, Myoclonic seizures, Atonic seizures, Concurrent electromyographyTonic-clonic (grand mal) seizures


2017 ◽  
Vol 24 (3) ◽  
pp. 712-736 ◽  
Author(s):  
Jérémie Cornut

Immersed in the flow of activities, diplomats and other international practitioners are simultaneously influenced by past experiences and constantly innovating in response to situations that are never exactly the same. The conceptual tools of International Relations scholars must be capable of capturing this practical reality. To that end, I introduce in this article a relational approach to agency that can make sense of practitioners’ innovative ways of doing things in practice. Practice theorists in IR often emphasize hierarchies, struggle, and the role of habitus in shaping practices. Both building on and departing from them, I dig into the logic of practical sense and discuss Pierre Bourdieu’s concepts of regulated improvisations, virtuosos/amateurs, and illusio to grasp agency in practice. I develop the idea that international actors are primarily practical and put improvisations and virtuosity — rather than rationality, cognitive processes, emotions, norm-compliance, path-dependency or even habits/habitus — in the foreground. I contend that this approach holds broader promise for the analysis of international politics than existing conceptions. We have much to gain by focusing on how international practitioners in their local contexts actually improvise in the moment. These improvisations in specific sites are constitutive of the ‘big picture’ of international politics. I take diplomatic practices in embassies and in permanent representations as an illustration.


2019 ◽  
Author(s):  
Deniz Ertekin ◽  
Leonie Kirszenblat ◽  
Richard Faville ◽  
Bruno van Swinderen

AbstractSleep is vital for survival. Yet, under environmentally challenging conditions such as starvation, animals suppress their need for sleep. Interestingly, starvation-induced sleep loss does not evoke a subsequent sleep rebound. Little is known about how starvation-induced sleep deprivation differs from other types of sleep loss, or why some sleep functions become dispensable during starvation. Here we demonstrate that downregulation of unpaired-2 (upd2, the Drosophila ortholog of leptin), is sufficient to mimic a starved-like state in flies. We use this ‘genetically starved’ state to investigate the consequences of a starvation signal on visual attention and sleep in otherwise well-fed flies, thereby sidestepping the negative side-effects of undernourishment. We find that knockdown of upd2 in the fat body is sufficient to suppress sleep while also increasing selective visual attention and promoting night-time feeding. Further, we show that this peripheral signal is integrated in the fly brain via insulin-expressing cells. Together, these findings identify a role for peripheral tissue-to-brain interactions in the simultaneous regulation of sleep and attention, to potentially promote adaptive behaviors necessary for survival in hungry animals.Author SummarySleep is important for maintaining both physiological (e.g., metabolic, immunological, and developmental) and cognitive processes, such as selective attention. Under nutritionally impoverished conditions, animals suppress sleep and increase foraging to locate food. Yet it is currently unknown how an animal is able to maintain well-tuned cognitive processes, despite being sleep deprived. Here we investigate this question by studying flies that have been genetically engineered to lack a satiety signal, and find that signaling from fat bodies in the periphery to insulin-expressing cells in the brain simultaneously regulates sleep need and attention-like processes.


Author(s):  
Zahra Mousavi ◽  
Mohammad Mahdi Kiani ◽  
Hamid Aghajan

AbstractThe brain is constantly anticipating the future of sensory inputs based on past experiences. When new sensory data is different from predictions shaped by recent trends, neural signals are generated to report this surprise. Existing models for quantifying surprise are based on an ideal observer assumption operating under one of the three definitions of surprise set forth as the Shannon, Bayesian, and Confidence-corrected surprise. In this paper, we analyze both visual and auditory EEG and auditory MEG signals recorded during oddball tasks to examine which temporal components in these signals are sufficient to decode the brain’s surprise based on each of these three definitions. We found that for both recording systems the Shannon surprise is always significantly better decoded than the Bayesian surprise regardless of the sensory modality and the selected temporal features used for decoding.Author summaryA regression model is proposed for decoding the level of the brain’s surprise in response to sensory sequences using selected temporal components of recorded EEG and MEG data. Three surprise quantification definitions (Shannon, Bayesian, and Confidence-corrected surprise) are compared in offering decoding power. Four different regimes for selecting temporal samples of EEG and MEG data are used to evaluate which part of the recorded data may contain signatures that represent the brain’s surprise in terms of offering a high decoding power. We found that both the middle and late components of the EEG response offer strong decoding power for surprise while the early components are significantly weaker in decoding surprise. In the MEG response, we found that the middle components have the highest decoding power while the late components offer moderate decoding powers. When using a single temporal sample for decoding surprise, samples of the middle segment possess the highest decoding power. Shannon surprise is always better decoded than the other definitions of surprise for all the four temporal feature selection regimes. Similar superiority for Shannon surprise is observed for the EEG and MEG data across the entire range of temporal sample regimes used in our analysis.


2019 ◽  
Author(s):  
Ulrik Beierholm ◽  
Tim Rohe ◽  
Ambra Ferrari ◽  
Oliver Stegle ◽  
Uta Noppeney

AbstractTo form the most reliable percept of the environment, the brain needs to represent sensory uncertainty. Current theories of perceptual inference assume that the brain computes sensory uncertainty instantaneously and independently for each stimulus.In a series of psychophysics experiments human observers localized auditory signals that were presented in synchrony with spatially disparate visual signals. Critically, the visual noise changed dynamically over time with or without intermittent jumps. Our results show that observers integrate audiovisual inputs weighted by sensory reliability estimates that combine information from past and current signals as predicted by an optimal Bayesian learner or approximate strategies of exponential discountingOur results challenge classical models of perceptual inference where sensory uncertainty estimates depend only on the current stimulus. They demonstrate that the brain capitalizes on the temporal dynamics of the external world and estimates sensory uncertainty by combining past experiences with new incoming sensory signals.


2015 ◽  
Vol 38 ◽  
Author(s):  
Julian Kiverstein ◽  
Mark Miller

AbstractPessoa (2013) makes a compelling case for conceiving of emotion and cognition as deeply integrated processes in the brain. We will begin our commentary by asking what implications this view of the brain has for an ontology of cognition – a theory of what cognition is and what cognitive processes exist. We will suggest that Pessoa's book, The Cognitive-Emotional Brain, provides strong support for an embodied theory of cognition. We end our commentary by offering some speculation about how Pessoa's arguments naturally extend to social cognition.


2008 ◽  
Vol 28 ◽  
pp. 191-204 ◽  
Author(s):  
Ching-fen Hsu ◽  
Annette Karmiloff-Smith

Most aspects of human life—from gene expression, to brain structure/function, to underlying linguistic and cognitive processes, through to overt language production and comprehension behaviors—are the result of dynamic developmental processes, in which timing plays a crucial role. So, the study of language acquisition in developmental disorders such as Williams syndrome (WS) needs to change from the still widely held view that developmental disorders can be accounted for in terms of spared versus impaired modules to one that takes serious account of the fact that the infant cortex passes from an initial state of high regional interconnectivity to a subsequent state of progressively increasing specialization and localization of functional brain networks. With such early interconnectivity in mind, developmental neuroscientists must explore the possibility that a small perturbation in low-level processes in one part of the brain very early in development can result in serious deficits in higher-level processes in another part of the brain later in development. Therefore, in profiling developmental disorders of language such as in WS, it is vital to start in early infancy, from which to trace the full trajectory of the interactions of language and other cognitive processes across infancy, toddlerhood, and childhood, through to adolescence and adulthood.


Author(s):  
Giuseppe Curcio ◽  
Sara Peracchia

In the last years, it is ever more frequent to read popular press stories about the effects of video and/or computer games on the brain and on the behavior. In some cases, we can read something claiming that video games “damage the brain,” while in others these activities can “boost brain power,” and such conflicting proclamation create confusion about the real or potential effects of this activity on human beings. Thus, it is very interesting to deeply understand the effect that exposure to video games (VGs) can have on cognitive processes, with particular attention to decision making. Only a few studies have been carried out on this issue: the main aim of this contribution is to clarify these aspects, critically reviewing the existing scientific literature. Particular attention has been dedicated to normal and pathological players, different types of VGs, and moral aspects of decision making vulnerable to VGs. It has been concluded that research in this area is still in its early days, and this short review aims at discussing several issues and challenges that should be addressed to forward this research field.


Author(s):  
Ebrahim Oshni Alvandi

One way to evaluate cognitive processes in living or nonliving systems is by using the notion of “information processing”. Emotions as cognitive processes orient human beings to recognize, express and display themselves or their wellbeing through dynamical and adaptive form of information processing. In addition, humans behave or act emotionally in an embodied environment. The brain embeds symbols, meaning and purposes for emotions as well. So any model of natural or autonomous emotional agents/systems needs to consider the embodied features of emotions that are processed in an informational channel of the brain or a processing system. This analytical and explanatory study described in this chapter uses the pragmatic notion of information to develop a theoretical model for emotions that attempts to synthesize some essential aspects of human emotional processing. The model holds context-sensitive and purpose-based features of emotional pattering in the brain. The role of memory is discussed and an idea of control parameters that have roles in processing environmental variables in emotional patterning is introduced.


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