scholarly journals Forgetting Is a Feature, Not a Bug: Intentionally Forgetting Some Things Helps Us Remember Others by Freeing Up Working Memory Resources

2019 ◽  
Vol 30 (9) ◽  
pp. 1303-1317 ◽  
Author(s):  
Vencislav Popov ◽  
Ivan Marevic ◽  
Jan Rummel ◽  
Lynne M. Reder
Keyword(s):  
Word Pair ◽  
Limited Resource ◽  
Directed Forgetting ◽  
Memory Formation ◽  
Verbal Rehearsal ◽  
Dual Task Paradigm ◽  
List Experiment ◽  
Memory Resources ◽  
Preceding Study ◽  
Over Time

In the present study, we used an item-method directed-forgetting paradigm to test whether instructions to forget or remember one item affect memory for subsequently studied items. In two experiments ( Ns = 138 and 33, respectively), recall was higher when a word pair was preceded during study by a to-be-forgotten word pair. This effect was cumulative: Performance increased when more preceding study items were to be forgotten. The effect decreased when memory was conditioned on instructions for items appearing farther back in the study list. Experiment 2 used a dual-task paradigm that suppressed, during encoding, verbal rehearsal or attentional refreshing. Neither task removed the effect, ruling out that rehearsal or attentional borrowing is responsible for the advantage conferred from previous to-be-forgotten items. We propose that memory formation depletes a limited resource that recovers over time and that to-be-forgotten items consume fewer resources, leaving more resources available for storing subsequent items. A computational model implementing the theory provided excellent fits to the data.

scholarly journals Forgetting is a Feature, not a Bug: Intentionally Forgetting Some Things Helps Us Remember Others by Freeing up Working Memory Resources

2018 ◽  
Author(s):  
Vencislav Popov ◽  
Ivan Marevic ◽  
Jan Rummel ◽  
Lynne Reder
Keyword(s):  
Word Pair ◽  
Cued Recall ◽  
Long Term Memory ◽  
Term Memory ◽  
Verbal Rehearsal ◽  
Dual Task Paradigm ◽  
Memory Resources ◽  
Over Time ◽  
Prior Item

We used an item-method directed forgetting paradigm to test whether instructions to forget or to remember one item in a list affects memory for the subsequent item in that list. In two experiments, we found that free and cued recall were higher when a word-pair was preceded during study by a to-be-forgotten (TBF) word pair. This effect was cumulative – performance was higher when more of the preceding items during study were TBF. It also interacted with lag between study items – the effect decreased as the lag between the current and a prior item increased. Experiment 2 used a dual-task paradigm in which we suppressed either verbal rehearsal or attentional refreshing during encoding. We found that neither task removed the effect, thus the advantage from previous TBF items could not be due to rehearsal or attentional borrowing. We propose that storing items in long-term memory depletes a limited pool of resources that recovers over time, and that TBF items deplete fewer resources, leaving more available for storing subsequent items. A computational model implementing the theory provided excellent fits to the data.

scholarly journals Odor-dependent temporal dynamics in C. elegans odor memory

2018 ◽  
Author(s):  
Jae Im Choi ◽  
Hee Kyung Lee ◽  
Hae Su Kim ◽  
So Young Park ◽  
Kyoung-hye Yoon ◽  
...  
Keyword(s):  
Sensory Neuron ◽  
Temporal Dynamics ◽  
Memory Formation ◽  
Nuclear Accumulation ◽  
C Elegans ◽  
Odor Memory ◽  
Dependent Protein ◽  
Enormous Number ◽  
Specific Odor ◽  
Over Time

Animals sense an enormous number of cues in their environments, and, over time, can form memories and associations to some of these. The nervous system remarkably maintains the specificity of memory to each of the cues. Here we asked whether the nematode Caenorhabditis elegans adjusts the temporal dynamics of odor memory formation depending on the specific odor sensed. C. elegans senses a multitude of odors, and memory formation to some of these odors requires activity of the cGMP-dependent protein kinase EGL-4 in the AWC sensory neuron. We identified a panel of 17 attractive odors, some of which have not been tested before, and determined that the majority of these odors require the AWC primary sensory neuron for sensation. We then devised a novel assay to assess odor behavior over time for a single population of animals. We used this assay to evaluate the temporal dynamics of memory formation to 13 odors and find that memory formation occurs early in some odors and later in others. We then examined EGL-4 localization in early-trending and late-trending odors over time and found that the timing of memory formation correlated with the timing of nuclear accumulation of EGL-4 in the AWC neuron. We demonstrate that odor memory formation in C. elegans can be used as a model to study the timing of memory formation to different sensory cues.

4. Making memories

2017 ◽  
pp. 42-55
Author(s):  
Paul Klenerman
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune System ◽  
Adaptive Response ◽  
Memory Formation ◽  
Innate Immune ◽  
Over Time

The ability of the immune system to sense pathogens and how they can be targeted specifically needs to be tightly coordinated in space and over time. ‘Making memories’ considers how the immune response develops following exposure to a virus. To make effective memory, the immune response needs to be induced correctly or ‘primed’ during the initial stages of an infection. The first step is for the immune system to develop a response relating to the activation of the innate immune system. Without this, the adaptive response is often subsequently overwhelmed. The mechanics of memory formation and how this is then harnessed in current vaccines are described.

scholarly journals Longitudinal brain changes in MDD during emotional encoding: effects of presence and persistence of symptomatology

2019 ◽  
Vol 50 (8) ◽  
pp. 1316-1326 ◽  
Author(s):  
Hui Ai ◽  
Esther M. Opmeer ◽  
Jan-Bernard C. Marsman ◽  
Dick J. Veltman ◽  
Nic J. A. van der Wee ◽  
...  
Keyword(s):  
Depressive Symptoms ◽  
Symptom Severity ◽  
Recognition Task ◽  
Brain Activation ◽  
Emotional Memory ◽  
Symptomatic Improvement ◽  
Memory Formation ◽  
State Dependency ◽  
State Dependent ◽  
Over Time

AbstractBackgroundThe importance of the hippocampus and amygdala for disrupted emotional memory formation in depression is well-recognized, but it remains unclear whether functional abnormalities are state-dependent and whether they are affected by the persistence of depressive symptoms.MethodsThirty-nine patients with major depressive disorder and 28 healthy controls were included from the longitudinal functional magnetic resonance imaging (fMRI) sub-study of the Netherlands Study of Depression and Anxiety. Participants performed an emotional word-encoding and -recognition task during fMRI at baseline and 2-year follow-up measurement. At baseline, all patients were in a depressed state. We investigated state-dependency by relating changes in brain activation over time to changes in symptom severity. Furthermore, the effect of time spent with depressive symptoms in the 2-year interval was investigated.ResultsSymptom change was linearly associated with higher activation over time of the left anterior hippocampus extending to the amygdala during positive and negative word-encoding. Especially during positive word encoding, this effect was driven by symptomatic improvement. There was no effect of time spent with depression in the 2-year interval on change in brain activation. Results were independent of medication- and psychotherapy-use.ConclusionUsing a longitudinal within-subjects design, we showed that hippocampal–amygdalar activation during emotional memory formation is related to depressive symptom severity but not persistence (i.e. time spent with depression or ‘load’), suggesting functional activation patterns in depression are not subject to functional ‘scarring’ although this hypothesis awaits future replication.

scholarly journals Neural Activity in the Hippocampus and Perirhinal Cortex during Encoding Is Associated with the Durability of Episodic Memory

2010 ◽  
Vol 22 (11) ◽  
pp. 2652-2662 ◽  
Author(s):  
Valerie A. Carr ◽  
Indre V. Viskontas ◽  
Stephen A. Engel ◽  
Barbara J. Knowlton
Keyword(s):  
Neural Activity ◽  
Medial Temporal Lobe ◽  
Memory Performance ◽  
Perirhinal Cortex ◽  
Memory Formation ◽  
Short Delay ◽  
Parahippocampal Cortex ◽  
The Relationship ◽  
Over Time ◽  
Subsequent Memory Effect

Studies examining medial temporal lobe (MTL) involvement in memory formation typically assess memory performance after a single, short delay. Thus, the relationship between MTL encoding activity and memory durability over time remains poorly characterized. To explore this relationship, we scanned participants using high-resolution functional imaging of the MTL as they encoded object pairs; using the remember/know paradigm, we then assessed memory performance for studied items both 10 min and 1 week later. Encoding trials were classified as either subsequently recollected across both delays, transiently recollected (i.e., recollected at 10 min but not after 1 week), consistently familiar, or consistently forgotten. Activity in perirhinal cortex (PRC) and a hippocampal subfield comprising the dentate gyrus and CA fields 2 and 3 reflected successful encoding only when items were recollected consistently across both delays. Furthermore, in PRC, encoding activity for items that later were consistently recollected was significantly greater than that for transiently recollected and consistently familiar items. Parahippocampal cortex, in contrast, showed a subsequent memory effect during encoding of items that were recollected after 10 min, regardless of whether they also were recollected after 1 week. These data suggest that MTL subfields contribute uniquely to the formation of memories that endure over time, and highlight a role for PRC in supporting subsequent durable episodic recollection.

scholarly journals Modeling a Risk-Based Dynamic Bus Schedule Problem under No-Notice Evacuation Incorporated with Dynamics of Disaster, Supply, and Demand Conditions

2019 ◽  
Vol 2019 ◽  
pp. 1-17
Author(s):  
Menghui Li ◽  
Jinliang Xu ◽  
Leyu Wei ◽  
Xingli Jia ◽  
Chao Sun
Keyword(s):  
Emergency Preparedness ◽  
Transportation Network ◽  
Supply And Demand ◽  
Limited Resource ◽  
Time Varying ◽  
Routing Problem ◽  
Schedule Model ◽  
Evacuation Risk ◽  
Bus Schedule ◽  
Over Time

Apart from private traffic, the evacuation of transit-dependent population is also an essential component of emergency preparedness, especially under no-notice evacuation scenarios with limit evacuation horizon. In literature, most bus-based evacuation models for no-notice evacuation are established under implicit assumptions of uniform evacuation horizon among different pick-up locations or fixed bus fleet in the evacuation area. These constraints will distance their models from real-world situations, where evacuation horizon is various due to spatial distribution of pick-up locations and fleet size of bus available for allocation will increase over time in no-notice evacuation. This research presents a risk-based bus schedule model which is differentiated from the vehicle routing problem (VRP) and bus evacuation problem (BEP) in literature, including the objective and the time-dependent parameters. A quantified definition of evacuation risk for pick-up location with concerns of disaster dynamics and time-varying supply-demand conditions is proposed in this paper as a criterion for bus allocation, also acting as a reflection of social equity to some extent. A notion of time-evolving disadvantageous evacuation units (DEU) is introduced to represent the pick-up locations selected for bus allocation with limited resource. The binary integer linear programming (BILP) named risk-based bus schedule model incorporated with DEU notion can provide a reference for resource allocation in stage of both evacuation planning and operation for transit-dependent population. The proposed model structure can effectively capture the changes of evacuation risk among pick-up locations over time to realize real-time bus schedule. Numerical experiments are conducted using the transportation network of the city of Xi’an, China, to test the performance of the model. The applicability and comparison of different bus evacuation models are also discussed in this paper. This research provides insights into dealing with disaster dynamics and time-varying supply conditions in realistic bus-based no-notice evacuation operations.

scholarly journals Dissociation of Frontal and Medial Temporal Lobe Activity in Maintenance and Binding of Sequentially Presented Paired Associates

2009 ◽  
Vol 21 (7) ◽  
pp. 1244-1254 ◽  
Author(s):  
Jena B. Hales ◽  
Sarah L. Israel ◽  
Nicole C. Swann ◽  
James B. Brewer
Keyword(s):  
Prefrontal Cortex ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Memory Formation ◽  
Sequential Presentation ◽  
Paired Associates ◽  
Parahippocampal Cortex ◽  
New Evidence ◽  
Response Specificity ◽  
Over Time

Substructures of the prefrontal cortex (PFC) and the medial-temporal lobe are critical for associating objects presented over time. Previous studies showing frontal and medial-temporal involvement in associative encoding have not addressed the response specificity of these regions to different aspects of the task, which include instructions to associate and binding of stimuli. This study used a novel paradigm to temporally separate these two components of the task by sequential presentation of individual images with or without associative instruction; fMRI was used to investigate the temporal involvement of the PFC and the parahippocampal cortex in encoding each component. Although both regions showed an enhanced response to the second stimulus of a pair, only the PFC had increased activation during the delay preceding a stimulus when associative instruction was given. These findings present new evidence that prefrontal and medial-temporal regions provide distinct temporal contributions during associative memory formation.

scholarly journals The Effect of Personalized Cueing on Long-Term Naming of Realistic Visual Stimuli

1995 ◽  
Vol 4 (4) ◽  
pp. 105-108 ◽  
Author(s):  
Donald B. Freed ◽  
Robert C. Marshall
Keyword(s):  
Associative Learning ◽  
Brain Damage ◽  
Word Pair ◽  
Visual Stimuli ◽  
Aphasia Therapy ◽  
Learning Techniques ◽  
Learning Procedure ◽  
Over Time

Associative learning techniques have been used successfully to teach word pair lists to subjects with brain damage. However, these techniques have not been used systematically to improve naming of complex visual stimuli such as might be found in aphasia therapy. This study examined the effect of an associative learning procedure, personalized cueing, on long-term naming of 40 realistic stimuli by 10 subjects with aphasia and 10 subjects without brain damage. The results showed that subjects without brain damage had significantly higher levels of naming accuracy than subjects with aphasia; however, subjects with aphasia were able to recall approximately 50% of the trained stimuli on both the 1-week and 30-day post-training probes. These results show that subjects with aphasia are able to use personalized cueing to learn effectively the names of items pictured in realistic visual stimuli and that the effects of training can be durable over time.

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