What happened when? Brain and behavioral responses to violated expectations about the structure and content of episodic memories

Episodic memories are not static but can be modified on the basis of new experiences, potentially allowing us to make valid predictions in the face of an ever-changing environment. Recent research has identified mnemonic prediction errors as a possible trigger for such modifications. In the present study, we investigated the influence of different types of mnemonic prediction errors on brain activity and subsequent memory performance using a novel paradigm for episodic modification. Participants encoded different episodes which consisted of short toy stories. During a subsequent functional magnetic resonance imaging (fMRI) session, episodic retrieval was cued by presenting videos showing the original episodes, or modified versions thereof. In modified videos either the order of two subsequent action steps was changed (violating structure expectancy) or an object was exchanged for another (violating content expectancy). While brain responses to structure expectancy violations were only subtle, content expectancy violations recruited brain areas relevant for processing of new object information. In a post-fMRI memory test, the participants' tendency to accept modified episodes as originally encoded increased significantly when they had experienced expectancy violations during the fMRI session. Our study provides valuable initial insights into the neural processing of different types of mnemonic prediction errors and their influence on subsequent memory.

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Inefficient Encoding as an Explanation for Age-Related Deficits in Recollection-Based Processing

Journal of Psychophysiology ◽

10.1027/0269-8803/a000122 ◽

2014 ◽

Vol 28 (3) ◽

pp. 148-161 ◽

Cited By ~ 12

Author(s):

David Friedman ◽

Ray Johnson

Keyword(s):

Older Adults ◽

Young Adults ◽

Cognitive Processes ◽

Brain Activity ◽

Memory Performance ◽

Brain Regions ◽

Semantic Retrieval ◽

Age Related ◽

The Face ◽

Episodic Memories

A cardinal feature of aging is a decline in episodic memory (EM). Nevertheless, there is evidence that some older adults may be able to “compensate” for failures in recollection-based processing by recruiting brain regions and cognitive processes not normally recruited by the young. We review the evidence suggesting that age-related declines in EM performance and recollection-related brain activity (left-parietal EM effect; LPEM) are due to altered processing at encoding. We describe results from our laboratory on differences in encoding- and retrieval-related activity between young and older adults. We then show that, relative to the young, in older adults brain activity at encoding is reduced over a brain region believed to be crucial for successful semantic elaboration in a 400–1,400-ms interval (left inferior prefrontal cortex, LIPFC; Johnson, Nessler, & Friedman, 2013 ; Nessler, Friedman, Johnson, & Bersick, 2007 ; Nessler, Johnson, Bersick, & Friedman, 2006 ). This reduced brain activity is associated with diminished subsequent recognition-memory performance and the LPEM at retrieval. We provide evidence for this premise by demonstrating that disrupting encoding-related processes during this 400–1,400-ms interval in young adults affords causal support for the hypothesis that the reduction over LIPFC during encoding produces the hallmarks of an age-related EM deficit: normal semantic retrieval at encoding, reduced subsequent episodic recognition accuracy, free recall, and the LPEM. Finally, we show that the reduced LPEM in young adults is associated with “additional” brain activity over similar brain areas as those activated when older adults show deficient retrieval. Hence, rather than supporting the compensation hypothesis, these data are more consistent with the scaffolding hypothesis, in which the recruitment of additional cognitive processes is an adaptive response across the life span in the face of momentary increases in task demand due to poorly-encoded episodic memories.

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Variations in Pupil Size Related to Memory for Recently Presented Words and Event Related Potentials

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01638 ◽

2020 ◽

pp. 1-09

Author(s):

Jan Rouke Kuipers ◽

William A. Phillips

Keyword(s):

Pupil Size ◽

Memory Performance ◽

Event Related Potentials ◽

Study Phase ◽

Attention And Memory ◽

Performance Study ◽

Brain Responses ◽

Different Types ◽

Related Potentials ◽

Initial List

Pupillometry has been found to be correlated with activity of cholinergic and noradrenergic neuromodulator systems. These systems regulate the level of cortical arousal and therefore perception, attention, and memory. Here, we tested how different types of pupil size variance (prestimulus baseline and prestimulus hippus power) may correlate with behavioral and electrophysiological brain responses (ERPs). We recorded pupil size and ERPs while participants were presented with a series of words and then asked whether they had been in the initial list when they were later presented intermixed with unpresented words. We found that a smaller prestimulus baseline pupil size during the study phase was associated with better memory performance. Study items also evoked a larger P3 response at presentation and a greater old/new memory ERP effect at test when prestimulus pupil size was small rather than large. Prestimulus hippus power was found to be a between-subjects factor affecting the robustness of memory encoding with less power being associated with a greater old/new memory ERP effect. These results provide evidence relating memory and ERPs to variables defined on pupil size that are thought to reflect varying states of parasympathetic and sympathetic arousal.

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Behavior in the Brain

Journal of Psychophysiology ◽

10.1027/0269-8803/a000016 ◽

2010 ◽

Vol 24 (2) ◽

pp. 76-82 ◽

Cited By ~ 15

Author(s):

Martin M. Monti ◽

Adrian M. Owen

Keyword(s):

Motor Behavior ◽

Functional Neuroimaging ◽

Brain Activity ◽

Motor Output ◽

The Unconscious ◽

Ethical Implications ◽

Brain Responses ◽

Minimally Conscious ◽

Brain Insults ◽

Brain Behavior

Recent evidence has suggested that functional neuroimaging may play a crucial role in assessing residual cognition and awareness in brain injury survivors. In particular, brain insults that compromise the patient’s ability to produce motor output may render standard clinical testing ineffective. Indeed, if patients were aware but unable to signal so via motor behavior, they would be impossible to distinguish, at the bedside, from vegetative patients. Considering the alarming rate with which minimally conscious patients are misdiagnosed as vegetative, and the severe medical, legal, and ethical implications of such decisions, novel tools are urgently required to complement current clinical-assessment protocols. Functional neuroimaging may be particularly suited to this aim by providing a window on brain function without requiring patients to produce any motor output. Specifically, the possibility of detecting signs of willful behavior by directly observing brain activity (i.e., “brain behavior”), rather than motoric output, allows this approach to reach beyond what is observable at the bedside with standard clinical assessments. In addition, several neuroimaging studies have already highlighted neuroimaging protocols that can distinguish automatic brain responses from willful brain activity, making it possible to employ willful brain activations as an index of awareness. Certainly, neuroimaging in patient populations faces some theoretical and experimental difficulties, but willful, task-dependent, brain activation may be the only way to discriminate the conscious, but immobile, patient from the unconscious one.

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Memory Processes, Aging, Cognitive Decline, and Neurodegenerative Diseases

European Psychologist ◽

10.1027/1016-9040.11.4.304 ◽

2006 ◽

Vol 11 (4) ◽

pp. 304-311 ◽

Cited By ~ 5

Author(s):

Lars-Göran Nilsson

Keyword(s):

Cognitive Impairment ◽

Cognitive Decline ◽

Neurodegenerative Disease ◽

Genetic Markers ◽

Brain Activity ◽

Memory Performance ◽

Modeling And Simulations ◽

Aging And Health ◽

Explained Variance ◽

Different Levels

This paper presents four domains of markers that have been found to predict later cognitive impairment and neurodegenerative disease. These four domains are (1) data patterns of memory performance, (2) cardiovascular factors, (3) genetic markers, and (4) brain activity. The critical features of each domain are illustrated with data from the longitudinal Betula Study on memory, aging, and health ( Nilsson et al., 1997 ; Nilsson et al., 2004 ). Up to now, early signs regarding these domains have been examined one by one and it has been found that they are associated with later cognitive impairment and neurodegenerative disease. However, it was also found that each marker accounts for only a very small part of the total variance, implying that single markers should not be used as predictors for cognitive decline or neurodegenerative disease. It is discussed whether modeling and simulations should be used as tools to combine markers at different levels to increase the amount of explained variance.

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Resting‐State EEG Microstates Parallel Age‐Related Differences in Allocentric Spatial Working Memory Performance

Brain Topography ◽

10.1007/s10548-021-00835-3 ◽

2021 ◽

Author(s):

Adeline Jabès ◽

Giuliana Klencklen ◽

Paolo Ruggeri ◽

Christoph M. Michel ◽

Pamela Banta Lavenex ◽

...

Keyword(s):

Older Adults ◽

Working Memory ◽

Resting State ◽

Cognitive Aging ◽

Temporal Dynamics ◽

Spatial Working Memory ◽

Brain Activity ◽

Memory Performance ◽

Brain Regions ◽

Age Related

AbstractAlterations of resting-state EEG microstates have been associated with various neurological disorders and behavioral states. Interestingly, age-related differences in EEG microstate organization have also been reported, and it has been suggested that resting-state EEG activity may predict cognitive capacities in healthy individuals across the lifespan. In this exploratory study, we performed a microstate analysis of resting-state brain activity and tested allocentric spatial working memory performance in healthy adult individuals: twenty 25–30-year-olds and twenty-five 64–75-year-olds. We found a lower spatial working memory performance in older adults, as well as age-related differences in the five EEG microstate maps A, B, C, C′ and D, but especially in microstate maps C and C′. These two maps have been linked to neuronal activity in the frontal and parietal brain regions which are associated with working memory and attention, cognitive functions that have been shown to be sensitive to aging. Older adults exhibited lower global explained variance and occurrence of maps C and C′. Moreover, although there was a higher probability to transition from any map towards maps C, C′ and D in young and older adults, this probability was lower in older adults. Finally, although age-related differences in resting-state EEG microstates paralleled differences in allocentric spatial working memory performance, we found no evidence that any individual or combination of resting-state EEG microstate parameter(s) could reliably predict individual spatial working memory performance. Whether the temporal dynamics of EEG microstates may be used to assess healthy cognitive aging from resting-state brain activity requires further investigation.

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Bi-Temporal Anodal Transcranial Direct Current Stimulation during Slow-Wave Sleep Boosts Slow-Wave Density but Not Memory Consolidation

Brain Sciences ◽

10.3390/brainsci11040410 ◽

2021 ◽

Vol 11 (4) ◽

pp. 410

Author(s):

Simon Ruch ◽

Kristoffer Fehér ◽

Stephanie Homan ◽

Yosuke Morishima ◽

Sarah Maria Mueller ◽

...

Keyword(s):

Episodic Memory ◽

Slow Wave ◽

Direct Current ◽

Memory Consolidation ◽

Transcranial Direct Current Stimulation ◽

Slow Wave Sleep ◽

Memory Performance ◽

Direct Current Stimulation ◽

Sleep Parameters ◽

Episodic Memories

Slow-wave sleep (SWS) has been shown to promote long-term consolidation of episodic memories in hippocampo–neocortical networks. Previous research has aimed to modulate cortical sleep slow-waves and spindles to facilitate episodic memory consolidation. Here, we instead aimed to modulate hippocampal activity during slow-wave sleep using transcranial direct current stimulation in 18 healthy humans. A pair-associate episodic memory task was used to evaluate sleep-dependent memory consolidation with face–occupation stimuli. Pre- and post-nap retrieval was assessed as a measure of memory performance. Anodal stimulation with 2 mA was applied bilaterally over the lateral temporal cortex, motivated by its particularly extensive connections to the hippocampus. The participants slept in a magnetic resonance (MR)-simulator during the recordings to test the feasibility for a future MR-study. We used a sham-controlled, double-blind, counterbalanced randomized, within-subject crossover design. We show that stimulation vs. sham significantly increased slow-wave density and the temporal coupling of fast spindles and slow-waves. While retention of episodic memories across sleep was not affected across the entire sample of participants, it was impaired in participants with below-average pre-sleep memory performance. Hence, bi-temporal anodal direct current stimulation applied during sleep enhanced sleep parameters that are typically involved in memory consolidation, but it failed to improve memory consolidation and even tended to impair consolidation in poor learners. These findings suggest that artificially enhancing memory-related sleep parameters to improve memory consolidation can actually backfire in those participants who are in most need of memory improvement.

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Active Inference: Applicability to Different Types of Social Organization Explained through Reference to Industrial Engineering and Quality Management

Entropy ◽

10.3390/e23020198 ◽

2021 ◽

Vol 23 (2) ◽

pp. 198

Author(s):

Stephen Fox

Keyword(s):

Artificial Intelligence ◽

Quality Management ◽

Social Organization ◽

Generative Models ◽

Industrial Engineering ◽

Prediction Errors ◽

Active Inference ◽

For Profit ◽

Different Types ◽

Inference Theory

Active inference is a physics of life process theory of perception, action and learning that is applicable to natural and artificial agents. In this paper, active inference theory is related to different types of practice in social organization. Here, the term social organization is used to clarify that this paper does not encompass organization in biological systems. Rather, the paper addresses active inference in social organization that utilizes industrial engineering, quality management, and artificial intelligence alongside human intelligence. Social organization referred to in this paper can be in private companies, public institutions, other for-profit or not-for-profit organizations, and any combination of them. The relevance of active inference theory is explained in terms of variational free energy, prediction errors, generative models, and Markov blankets. Active inference theory is most relevant to the social organization of work that is highly repetitive. By contrast, there are more challenges involved in applying active inference theory for social organization of less repetitive endeavors such as one-of-a-kind projects. These challenges need to be addressed in order for active inference to provide a unifying framework for different types of social organization employing human and artificial intelligence.

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Approaches to the Mechanical Properties of Threaded Studs Welded to RHS Columns

Materials ◽

10.3390/ma14061429 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1429

Author(s):

Ismael García ◽

Miguel A. Serrano ◽

Carlos López-Colina ◽

Fernando L. Gayarre ◽

Jesús M. Suárez

Keyword(s):

Mechanical Properties ◽

Tensile Tests ◽

Efficient Solutions ◽

Bolted Joints ◽

Building Structures ◽

Static Behavior ◽

Steel Tubes ◽

Punch Test ◽

Different Types ◽

The Face

The use of Rectangular Hollow Sections (RHS) as columns in steel construction includes important advantages like higher mechanical strength and fire resistance. However, the practical demountable bolted joints between beams and columns are not easy to execute, due to impossibility of access to the inner part of the tube. The use of threaded studs welded to the face of the tube and bolted to the beam by means of angle cleats is one of the cheaper and most efficient solutions to obtain beam–column joints with a semi-rigid behavior, as is usually sought in building structures. Nevertheless, it is important to point out that the stud-diameter and the stud-class selection may affect the mechanical properties of the welded parts of the joint. In this paper, 8MnSi7 (with a commercial designation K800) and 4.8 threaded studs were welded to RHS steel tubes and mechanical properties on the weld, the Heat Affected Zones (HAZ), and the base metal were obtained in two different ways: through a correlation with the Vickers hardness and by means of the Small Punch Test (SPT). A study of the microstructure and tensile tests on the threaded studs and in the columns was also carried out. The research involved different types of stud qualities, tube wall thicknesses, and stud diameters. The work presented in this paper proved that in most cases, the welded joint between these studs and the RHS steel tubes present a reasonable static behavior that fulfils the requirements for the beam–column joints under static loading.

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