scholarly journals Suppression weakens unwanted memories via a sustained reduction of neural reactivation

2021 ◽  
Author(s):  
Ann-Kristin Meyer ◽  
Roland G. Benoit
Keyword(s):  
Intrusive Memories ◽  
Neural Representations ◽  
Parahippocampal Cortex ◽  
Aversive Events ◽  
Fmri Study ◽  
Sustained Reduction ◽  
Memory Representations ◽  
Scene Information ◽  
The Right ◽  
Study Participants

Aversive events often turn into intrusive memories. However, prior evidence indicates that these memories can be forgotten via a mechanism of retrieval suppression. Here, we test the hypothesis that suppression weakens memories by deteriorating their neural representations. This deterioration, in turn, would hinder their subsequent reactivation and thus impoverish the vividness with which they can be recalled. In an fMRI study, participants repeatedly suppressed memories of aversive scenes. As predicted, this process rendered the memories less vivid. Using a pattern classifier, we observed that it did diminish the reactivation of scene information both globally across the grey matter and locally in the parahippocampal cortices. Moreover, in the right parahippocampal cortex, a stronger decline in vividness was associated with a greater reduction in generic reactivation of scene information and in the specific reinstatement of unique memory representations. These results support the hypothesis that suppression deteriorates memories by compromising their neural representations.

Brain Activity During Predictable and Unpredictable Weight Changes When Lifting Objects

2005 ◽  
Vol 93 (3) ◽  
pp. 1498-1509 ◽  
Author(s):  
Christina Schmitz ◽  
Per Jenmalm ◽  
H. Henrik Ehrsson ◽  
Hans Forssberg
Keyword(s):  
Brain Activity ◽  
Inferior Frontal Gyrus ◽  
Memory Systems ◽  
Synaptic Activity ◽  
Weight Changes ◽  
Fmri Study ◽  
Sensorimotor Memory ◽  
Memory Representations ◽  
The Right ◽  
Fingertip Forces

When humans repetitively lift the same object, the fingertip forces are targeted to the weight of the object. The anticipatory programming of the forces depends on sensorimotor memory representations that provide information on the object weight. In the present study, we investigate the neural substrates of these sensorimotor memory systems by recording the neural activity during predictable or unpredictable changes in the weight of an object in a lifting task. An unpredictable change in weight leads to erroneous programming of the fingertip forces. This triggers corrective mechanisms and an update of the sensorimotor memories. In the present fMRI study, healthy right-handed subjects repetitively lifted an object between right index finger and thumb. In the constant condition, which served as a control, the weight of the object remained constant (either 230 or 830 g). The weight alternated between 230 and 830 g during the regular condition and was irregularly changed between the two weights during the irregular condition. When we contrasted regular minus constant and irregular minus constant, we found activations in the right inferior frontal gyrus pars opercularis (area 44), the left parietal operculum and the right supramarginal gyrus. Furthermore, irregular was associated with stronger activation in the right inferior frontal cortex as compared with regular. Taken together, these results suggest that the updating of sensorimotor memory representations and the corrective reactions that occur when we manipulate different objects correspond to changes in synaptic activity in these fronto-parietal circuits.

scholarly journals Narratives as Networks: Predicting Memory from the Structure of Naturalistic Events

2021 ◽  
Author(s):  
Hongmi Lee ◽  
Janice Chen
Keyword(s):  
Memory Consolidation ◽  
Human Life ◽  
Discrete Events ◽  
Cortical Areas ◽  
Neural Representations ◽  
Causal Connections ◽  
Fmri Study ◽  
Memory Representations ◽  
Event Boundary ◽  
With Memory

ABSTRACTHuman life consists of a multitude of diverse and interconnected events. However, extant research has focused on how humans segment and remember discrete events from continuous input, with far less attention given to how the structure of connections between events impacts memory. We conducted an fMRI study in which subjects watched and recalled a series of realistic audiovisual narratives. By transforming narratives into networks of events, we found that more central events—those with stronger semantic or causal connections to other events—were better remembered. During encoding, central events evoked larger hippocampal event boundary responses associated with memory consolidation. During recall, high centrality predicted stronger activation in cortical areas involved in episodic recollection, and more similar neural representations across individuals. Together, these results suggest that when humans encode and retrieve complex real-world experiences, the reliability and accessibility of memory representations is shaped by their location within a network of events.

scholarly journals The Parahippocampal Cortex Mediates Contextual Associative Memory: Evidence from an fMRI Study

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Mi Li ◽  
Shengfu Lu ◽  
Ning Zhong
Keyword(s):  
Associative Memory ◽  
Cognitive Neuroscience ◽  
Contextual Information ◽  
Spatial Processing ◽  
Associative Processing ◽  
New Associations ◽  
Visual Objects ◽  
Parahippocampal Cortex ◽  
Fmri Study ◽  
The Right

The parahippocampal cortex (PHC) plays a key role in episodic memory, spatial processing, and the encoding of novel stimuli. Recent studies proposed that the PHC is largely involved in contextual associative processing. Consequently, the function of this region has been a hot debate in cognitive neuroscience. To test this assumption, we used two types of experimental materials to form the contextual associative memory: visual objects in reality and meaningless visual shapes. New associations were modeled from either the contextual objects or the contextual shapes. Both contextual objects and shapes activated the bilateral PHC more than the noncontextual ones. The contextual objects with semantics significantly activated the left PHC areas, whereas the meaningless contextual shapes significantly elicited the right PHC. The results clearly demonstrate that the PHC influences the processing of contextual information and provides experimental evidence for an understanding of the different functions of bilateral PHC in contextual associative memory.

scholarly journals Neural alignment predicts learning outcomes in students taking an introduction to computer science course

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Meir Meshulam ◽  
Liat Hasenfratz ◽  
Hanna Hillman ◽  
Yun-Fei Liu ◽  
Mai Nguyen ◽  
...  
Keyword(s):  
Computer Science ◽  
Learning Outcomes ◽  
Brain Activity ◽  
Activity Patterns ◽  
Real Life ◽  
Final Exam ◽  
Neural Representations ◽  
Real Life Setting ◽  
The Right ◽  
Mri Study

AbstractDespite major advances in measuring human brain activity during and after educational experiences, it is unclear how learners internalize new content, especially in real-life and online settings. In this work, we introduce a neural approach to predicting and assessing learning outcomes in a real-life setting. Our approach hinges on the idea that successful learning involves forming the right set of neural representations, which are captured in canonical activity patterns shared across individuals. Specifically, we hypothesized that learning is mirrored in neural alignment: the degree to which an individual learner’s neural representations match those of experts, as well as those of other learners. We tested this hypothesis in a longitudinal functional MRI study that regularly scanned college students enrolled in an introduction to computer science course. We additionally scanned graduate student experts in computer science. We show that alignment among students successfully predicts overall performance in a final exam. Furthermore, within individual students, we find better learning outcomes for concepts that evoke better alignment with experts and with other students, revealing neural patterns associated with specific learned concepts in individuals.

Improvement in prefrontal thalamic connectivity during the early course of the illness in recent-onset psychosis: a 12-month longitudinal follow-up resting-state fMRI study

2020 ◽  
pp. 1-9
Author(s):  
Daniel Bergé ◽  
Tyler A. Lesh ◽  
Jason Smucny ◽  
Cameron S. Carter
Keyword(s):  
Resting State ◽  
Resting State Fmri ◽  
Functional Changes ◽  
Recent Onset ◽  
Fmri Study ◽  
Clinical Meaning ◽  
Mixed Pattern ◽  
The Right ◽  
Over Time

Abstract Background Previous research in resting-state functional magnetic resonance imaging (rs-fMRI) has shown a mixed pattern of disrupted thalamocortical connectivity in psychosis. The clinical meaning of these findings and their stability over time remains unclear. We aimed to study thalamocortical connectivity longitudinally over a 1-year period in participants with recent-onset psychosis. Methods To this purpose, 129 individuals with recent-onset psychosis and 87 controls were clinically evaluated and scanned using rs-fMRI. Among them, 43 patients and 40 controls were re-scanned and re-evaluated 12 months later. Functional connectivity between the thalamus and the rest of the brain was calculated using a seed to voxel approach, and then compared between groups and correlated with clinical features cross-sectionally and longitudinally. Results At baseline, participants with recent-onset psychosis showed increased connectivity (compared to controls) between the thalamus and somatosensory and temporal regions (k = 653, T = 5.712), as well as decreased connectivity between the thalamus and left cerebellum and right prefrontal cortex (PFC; k = 201, T = −4.700). Longitudinal analyses revealed increased connectivity over time in recent-onset psychosis (relative to controls) in the right middle frontal gyrus. Conclusions Our results support the concept of abnormal thalamic connectivity as a core feature in psychosis. In agreement with a non-degenerative model of illness in which functional changes occur early in development and do not deteriorate over time, no evidence of progressive deterioration of connectivity during early psychosis was observed. Indeed, regionally increased connectivity between thalamus and PFC was observed.

scholarly journals Brain Activation during Thoughts of One’s Own Death and Its Linear and Curvilinear Correlations with Fear of Death in Elderly Individuals: An fMRI Study

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Kanan Hirano ◽  
Kentaro Oba ◽  
Toshiki Saito ◽  
Shohei Yamazaki ◽  
Ryuta Kawashima ◽  
...  
Keyword(s):  
Brain Activation ◽  
Posterior Cingulate Cortex ◽  
Fear Of Death ◽  
Supramarginal Gyrus ◽  
Brain Responses ◽  
Fmri Study ◽  
Negative Linear Correlation ◽  
The Right ◽  
Older Populations ◽  
Existential Issues

Abstract Facing one’s own death and managing the fear of death are important existential issues, particularly in older populations. Although recent functional magnetic resonance imaging (fMRI) studies have investigated brain responses to death-related stimuli, none has examined whether this brain activation was specific to one’s own death or how it was related to dispositional fear of death. In this study, during fMRI, 34 elderly participants (aged, 60–72 years) were presented with either death-related or death-unrelated negative words and asked to evaluate the relevance of these words to the “self” or the “other.” The results showed that only the left supplementary motor area (SMA) was selectively activated during self-relevant judgments of death-related words. Regression analyses of the effect of fear of death on brain activation during death-related thoughts identified a significant negative linear correlation in the right supramarginal gyrus (SMG) and an inverted-U-shaped correlation in the posterior cingulate cortex (PCC) only during self-relevant judgments. Our results suggest potential involvement of the SMA in the existential aspect of thoughts of death. The distinct fear-of-death-dependent responses in the SMG and PCC may reflect fear-associated distancing of the physical self and the processing of death-related thoughts as a self-relevant future agenda, respectively.

Brain Network Dysfunction in Poststroke Delirium and Spatial Neglect: An fMRI Study

Stroke ◽  
2021 ◽  
Author(s):  
Olga Boukrina ◽  
Mateusz Kowalczyk ◽  
Yury Koush ◽  
Yekyung Kong ◽  
A.M. Barrett
Keyword(s):  
Right Hemisphere ◽  
Functional Neuroimaging ◽  
Brain Network ◽  
Spatial Neglect ◽  
Stroke Recovery ◽  
Network Activity ◽  
Brain Disorder ◽  
Fmri Study ◽  
The Right ◽  
Right Hemisphere Stroke

Background and Purpose: Delirium, an acute reduction in cognitive functioning, hinders stroke recovery and contributes to cognitive decline. Right-hemisphere stroke is linked with higher delirium incidence, likely, due to the prevalence of spatial neglect (SN), a right-brain disorder of spatial processing. This study tested if symptoms of delirium and SN after right-hemisphere stroke are associated with abnormal function of the right-dominant neural networks specialized for maintaining attention, orientation, and arousal. Methods: Twenty-nine participants with right-hemisphere ischemic stroke undergoing acute rehabilitation completed delirium and SN assessments and functional neuroimaging scans. Whole-brain functional connectivity of 4 right-hemisphere seed regions in the cortical-subcortical arousal and attention networks was assessed for its relationship to validated SN and delirium severity measures. Results: Of 29 patients, 6 (21%) met the diagnostic criteria for delirium and 16 (55%) for SN. Decreased connectivity of the right basal forebrain to brain stem and basal ganglia predicted more severe SN. Increased connectivity of the arousal and attention network regions with the parietal, frontal, and temporal structures in the unaffected hemisphere was also found in more severe delirium and SN. Conclusions: Delirium and SN are associated with decreased arousal network activity and an imbalance of cortico-subcortical hemispheric connectivity. Better understanding of neural correlates of poststroke delirium and SN will lead to improved neuroscience-based treatment development for these disorders.

IMMIGRANT RIGHTS IN A DEEP SOUTH CITY

2016 ◽  
Vol 13 (1) ◽  
pp. 139-157 ◽  
Author(s):  
Kim M. Williams ◽  
Lonnie Hannon
Keyword(s):  
Civil Rights ◽  
State Legislature ◽  
Deep South ◽  
Event Analysis ◽  
Immigrant Rights ◽  
Local Newspapers ◽  
Immigration Debate ◽  
Black Elite ◽  
The Right ◽  
Study Participants

AbstractIn 2010, the Alabama GOP took control of the state legislature for the first time since Reconstruction. The next year, in a sharply partisan vote, the legislature passed, and Governor Robert Bentley (R) signed into law, the Beason-Hammon Alabama Taxpayer and Citizen Protection Act, also known as House Bill 56, the harshest immigration law in the country. This punitive state law was the impetus for Black elites in Birmingham to frame the immigration debate as a matter of civil rights and thus to see the issue in a new light. When Alabama Republicans moved to the Right on immigration, Black leaders in Birmingham moved Left. In this study, backed up by an event analysis of local newspapers, an analysis of interviews with members of the Black elite in Birmingham in 2013, who were previously interviewed in 2007, helps to substantiate this claim. In the summer of 2007, against the backdrop of an immigration debate in Washington, our Black elite study participants largely told us they had no stake in immigration. By 2013, many were willing to fight for immigrant rights at the highest level.

Effects of State Dissociation on Objectively and Subjectively assessed Memory Disturbances

2006 ◽  
Vol 34 (3) ◽  
pp. 319-331 ◽  
Author(s):  
Nicole Buck ◽  
Merel Kindt ◽  
Marcel van den Hout
Keyword(s):  
Information Processing ◽  
Traumatic Experience ◽  
Spider Phobia ◽  
New Approach ◽  
Perceptual Memory ◽  
Aversive Events ◽  
Memory Representations ◽  
State Dissociation ◽  
The Impact ◽  
Experimentally Induced

Dissociation often occurs after a traumatic experience and has detrimental effects on memory. If these supposed detrimental effects are the result of disturbances in information processing, not only subjectively assessed but also objectively assessed memory disturbances should be observed. Most studies assessing dissociation and memory in the context of trauma have studied trauma victims. However, this study takes a new approach in that the impact of experimentally induced state dissociation on memory is investigated in people with spider phobia. Note that the aim of the present study was not to test the effect of trauma on memory disturbances. We found indeed significant relations between state dissociation and subjectively assessed memory disturbances: intrusions and self-rated memory fragmentation. Moreover, although no relation was found between state dissociation and experimenter-rated memory fragmentation, we observed a relation between state dissociation and experimenter-rated perceptual memory representations. These results show that state dissociation indeed has detrimental effects on the processing of aversive events.

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