scholarly journals Distinct Hippocampal versus Frontoparietal Network Contributions to Retrieval and Memory-guided Exploration

2017 ◽  
Vol 29 (8) ◽  
pp. 1324-1338 ◽  
Author(s):  
Donna J. Bridge ◽  
Neal J. Cohen ◽  
Joel L. Voss
Keyword(s):  
Learning Strategies ◽  
Memory Retrieval ◽  
Passive Control ◽  
Frontoparietal Network ◽  
Guided Learning ◽  
Hippocampal Activity ◽  
Guided Exploration ◽  
Memory Representations ◽  
Time Lagged ◽  
Retrieval From Memory

Memory can profoundly influence new learning, presumably because memory optimizes exploration of to-be-learned material. Although hippocampus and frontoparietal networks have been implicated in memory-guided exploration, their specific and interactive roles have not been identified. We examined eye movements during fMRI scanning to identify neural correlates of the influences of memory retrieval on exploration and learning. After retrieval of one object in a multiobject array, viewing was strategically directed away from the retrieved object toward nonretrieved objects, such that exploration was directed toward to-be-learned content. Retrieved objects later served as optimal reminder cues, indicating that exploration caused memory to become structured around the retrieved content. Hippocampal activity was associated with memory retrieval, whereas frontoparietal activity varied with strategic viewing patterns deployed after retrieval, thus providing spatiotemporal dissociation of memory retrieval from memory-guided learning strategies. Time-lagged fMRI connectivity analyses indicated that hippocampal activity predicted frontoparietal activity to a greater extent for a condition in which retrieval guided exploration occurred than for a passive control condition in which exploration was not influenced by retrieval. This demonstrates network-level interaction effects specific to influences of memory on strategic exploration. These findings show how memory guides behavior during learning and demonstrate distinct yet interactive hippocampal–frontoparietal roles in implementing strategic exploration behaviors that determine the fate of evolving memory representations.

Going Their Separate Ways: Dissociation of Hippocampal and Dorsolateral Prefrontal Activation during Episodic Retrieval and Post-retrieval Processing

2010 ◽  
Vol 22 (3) ◽  
pp. 513-525 ◽  
Author(s):  
Sarah L. Israel ◽  
Tyler M. Seibert ◽  
Michelle L. Black ◽  
James B. Brewer
Keyword(s):  
Episodic Memory ◽  
Memory Retrieval ◽  
Relative Increase ◽  
Network Activity ◽  
Default Network ◽  
Episodic Retrieval ◽  
Retrieval Task ◽  
Paired Associates ◽  
Hippocampal Activity ◽  
Dorsolateral Prefrontal

Hippocampal activity is modulated during episodic memory retrieval. Most consistently, a relative increase in activity during confident retrieval is observed. Dorsolateral prefrontal cortex (DLPFC) is also activated during retrieval, but may be more generally activated during cognitive-control processes. The “default network,” regions activated during rest or internally focused tasks, includes the hippocampus, but not DLPFC. Therefore, DLPFC and the hippocampus should diverge during difficult tasks suppressing the default network. It is unclear, however, whether a difficult episodic memory retrieval task would suppress the default network due to difficulty or activate it due to internally directed attention. We hypothesized that a task requiring episodic retrieval followed by rumination on the retrieved item would increase DLPFC activity, but paradoxically reduce hippocampal activity due to concomitant suppression of the default network. In the present study, blocked and event-related fMRI were used to examine hippocampal activity during episodic memory recollection and postretrieval processing of paired associates. Subjects were asked to make living/nonliving judgments about items visually presented (classify) or items retrieved from memory (recall–classify). Active and passive baselines were used to differentiate task-related activity from default-network activity. During the “recall–classify” task, anterior hippocampal activity was selectively reduced relative to “classify” and baseline tasks, and this activity was inversely correlated with DLPFC. Reaction time was positively correlated with DLPFC activation and default-network/hippocampal suppression. The findings demonstrate that frontal and hippocampal activity are dissociated during difficult episodic retrieval tasks and reveal important considerations for interpreting hippocampal activity associated with successful episodic retrieval.

scholarly journals Use of Diverse Online Resources amongst Politically Active University Students Fosters Civic Knowledge Integration

2019 ◽  
Vol 14 (2) ◽  
pp. 131-133
Author(s):  
Joanne Muellenbach
Keyword(s):  
Focus Group ◽  
University Students ◽  
Learning Strategies ◽  
Knowledge Integration ◽  
Public Affairs ◽  
Civic Knowledge ◽  
Guided Learning ◽  
New Information ◽  
Group Interviews ◽  
Politically Active

A Review of: Soe, Y. (2018) Understanding politics more thoroughly: How highly engaged young citizens use the Internet for civic knowledge integration. First Monday, 23(6), 1-17. http://doi.org/10.5210/fm.v23i6.7923 Abstract Objective – To examine the process by which university students with a high interest in politics and public affairs incorporate new information into their understanding of politics and public affairs, a process referred to as civic knowledge integration. Design – This study utilized a qualitative research design that consisted of focus group interviews and essay questions. Setting – Two large four-year Midwestern public universities and two four-year East coast private universities in the United States of America in 2008 and 2010. Subjects – A total of 65 undergraduate and graduate (masters) students participated in the focus group interviews and answered essay questions by e-mail. Methods – In 2008, the researcher conducted 11 focus groups consisting of 5 to 7 participants per group. In 2010, additional data were collected from students at another large four-year Midwestern public university who responded by e-mail to essay questions that were adapted from those used in the focus groups. Recruitment of participants was achieved by contacting professors of media and political science at the universities and targeting students with interest in media, politics, and public affairs, and who were politically active. Course credit or a small monetary incentive was offered to students as compensation. Data resulting from the focus group and essay responses were combined and imported into the QDA Miner software. Data analysis, which used some techniques of grounded theory, was conducted in two phases. In the first phase, 120 analyzable subsets were identified, and open coding of 36 subsets was performed to determine themes. These themes were then modified and renamed using an axial and selective coding process. Examples of resulting topics included collaborative layering of ideas, comparison of differing viewpoints, and monitorial scanning. The second phase involved coding of the 120 subsets, and 65 subgroups that focused on civic knowledge integration were identified. Ultimately, open, thematic coding of the 65 subsets was performed to identify comments that contained the most common themes. Main Results – An analysis of the data revealed that participants used the resulting themes as self-guided learning strategies when searching the Internet for civic knowledge integration, the process by which university students with a high interest in politics and public affairs incorporate new information into their understanding of these areas. One of the strategies used was a two-step process of monitorial scanning and opinion sampling. Monitorial scanning involves the careful selection of search engines in order to scan the news and determine their potential levels of interest, and the use of online encyclopedias such as Wikipedia to locate background information and other details. Opinion sampling involves the process of sorting the sources found, such as blogs and candidates’ web pages. Another strategy used was verification (cross-checking), which consisted of checking multiple sources to find more information on a particular news item or news show, such as those watched on CNN.com. Comparison of differing and opposing viewpoints was another strategy used, that involved the comparing of information about political candidates' perspectives or views to justify their own opinions. Finally, collaborative layering of ideas was a strategy that involved participation in online forums, such as Facebook. This strategy provided participants with the opportunity to express their thoughts and opinions globally, and to contribute to a change in a set practice.    Conclusion – Through the use of strategies for self-guided learning, participants were able to add new information to their knowledge base and to develop new points of view. These students developed advanced search strategies and took pleasure in finding opposing perspectives, and as a result, enhanced their critical thinking skills. The conclusions also increased general knowledge of why young people used specific online platforms, information resources, or social media sites to enhance their understanding of politics and public affairs. These findings may also challenge media and political science to investigate the long-term effects of self-guided learning strategies for civic knowledge integration practiced by some young people.

scholarly journals Hippocampal–Cortical Encoding Activity Predicts the Precision of Episodic Memory

2021 ◽  
pp. 1-14
Author(s):  
Saana M. Korkki ◽  
Franziska R. Richter ◽  
Jon S. Simons
Keyword(s):  
Memory Retrieval ◽  
Neural Substrates ◽  
Memory Formation ◽  
Continuous Scale ◽  
Neuroimaging Data ◽  
Memory Representations ◽  
Past Experiences ◽  
Object Features ◽  
Memory Precision ◽  
Continuous Measures

Abstract Our recollections of past experiences can vary in both the number of specific event details accessible from memory and the precision with which such details are reconstructed. Prior neuroimaging evidence suggests the success and precision of episodic recollection to rely on distinct neural substrates during memory retrieval. In contrast, the specific encoding mechanisms supporting later memory precision, and whether they differ from those underlying successful memory formation in general, are currently unknown. Here, we combined continuous measures of memory retrieval with model-based analyses of behavioral and neuroimaging data to tease apart the encoding correlates of successful memory formation and mnemonic precision. In the MRI scanner, participants encoded object-scene displays and later reconstructed features of studied objects using a continuous scale. We observed overlapping encoding activity in inferior prefrontal and posterior perceptual regions to predict both which object features were later remembered versus forgotten and the precision with which they were reconstructed from memory. In contrast, hippocampal encoding activity significantly predicted the precision, but not overall success, of subsequent memory retrieval. The current results align with theoretical accounts proposing the hippocampus to be critical for representation of high-fidelity associative information and suggest a contribution of shared cortical encoding mechanisms to the formation of both accessible and precise memory representations.

scholarly journals On Efficiency of Strategy-Based Learning in Achieving Autonomy Competence among Algerian Undergraduate Learners

2020 ◽  
Vol 06 (11) ◽  
Author(s):  
MAROUA ROGTI ◽  
Keyword(s):  
Instructional Strategies ◽  
Learning Strategies ◽  
Teaching And Learning ◽  
Learning Strategy ◽  
Self Directed Learning ◽  
Language Class ◽  
Guided Learning ◽  
Directed Learning ◽  
English Literacy ◽  
Based Instruction

In the last decade, there has been an eminent shift towards a relative emphasis on achievement, competence, and autonomy in the language teaching and learning arena. Prior to this, educationalists had a growing concern in how to gain academic achievement through considering learning strategies as part of classroom discourse. Further, instructional strategies can also gain a strategic position in the curriculum, so that learners can be self-directed and strategic learners. This can help them choose the appropriate learning strategy to successively accomplish tasks and meet the desired goals. This study would like to be a part of increasing the effectiveness of implementing Strategy-based Instruction for achieving self-guided learning and autonomy in the language class. It adapts a survey administered to three teachers of English literacy in order to elicit their views about dealing with tasks in teaching literature through instructional strategies to graduate students and their impact on achieving self-directed learning. Hence, it reported affirmative and practical outcomes from the previous studies and assumed the need for integrating instructional strategies prosperously into an ordinary literature task in class.

scholarly journals Lateral entorhinal cortex suppresses drift in cortical memory representations.

2021 ◽  
Author(s):  
Maryna Pilkiw ◽  
Justin Jarovi ◽  
Kaori Takehara-Nishiuchi
Keyword(s):  
Entorhinal Cortex ◽  
Memory Retrieval ◽  
Firing Pattern ◽  
Memory Trace ◽  
Male Rats ◽  
Memory Representations ◽  
Familiar Environment ◽  
Functional Relevance ◽  
The Stability ◽  
Cortical Representations

Memory retrieval is thought to depend on the reinstatement of cortical memory representations guided by pattern completion processes in the hippocampus. The lateral entorhinal cortex (LEC) is one of the intermediary regions supporting hippocampal-cortical interactions and houses neurons that prospectively signal past events in a familiar environment. To investigate the functional relevance of the LEC's activity for cortical reinstatement, we pharmacologically inhibited the LEC and examined its impact on the stability of ensemble firing patterns in one of the LEC's efferent targets, the medial prefrontal cortex (mPFC). When male rats underwent multiple epochs of identical stimulus sequences in the same environment, the mPFC maintained a stable ensemble firing pattern across repetitions, particularly when the sequence included pairings of neutral and aversive stimuli. With LEC inhibition, the mPFC still formed an ensemble pattern that accurately captured stimuli and their associations within each epoch. However, LEC inhibition markedly disrupted its consistency across the epochs by decreasing the proportion of mPFC neurons that stably maintained firing selectivity for stimulus associations. Thus, the LEC stabilizes cortical representations of learned stimulus associations, thereby facilitating the recovery of the original memory trace without generating a new, redundant trace for familiar experiences. Failure of this process might underlie retrieval deficits in conditions associated with degeneration of the LEC, such as normal aging and Alzheimer's disease.

scholarly journals Increasing neurogenesis refines hippocampal activity rejuvenating navigational learning strategies and contextual memory throughout life

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Gabriel Berdugo-Vega ◽  
Gonzalo Arias-Gil ◽  
Adrian López-Fernández ◽  
Benedetta Artegiani ◽  
Joanna M. Wasielewska ◽  
...  
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Learning Strategies ◽  
Inhibitory Effect ◽  
Cell Cycle Regulators ◽  
Contextual Memory ◽  
Age Related ◽  
Hippocampal Activity ◽  
Navigational Learning ◽  
The Brain

AbstractFunctional plasticity of the brain decreases during ageing causing marked deficits in contextual learning, allocentric navigation and episodic memory. Adult neurogenesis is a prime example of hippocampal plasticity promoting the contextualisation of information and dramatically decreases during ageing. We found that a genetically-driven expansion of neural stem cells by overexpression of the cell cycle regulators Cdk4/cyclinD1 compensated the age-related decline in neurogenesis. This triggered an overall inhibitory effect on the trisynaptic hippocampal circuit resulting in a changed profile of CA1 sharp-wave ripples known to underlie memory consolidation. Most importantly, increased neurogenesis rescued the age-related switch from hippocampal to striatal learning strategies by rescuing allocentric navigation and contextual memory. Our study demonstrates that critical aspects of hippocampal function can be reversed in old age, or compensated throughout life, by exploiting the brain’s endogenous reserve of neural stem cells.

scholarly journals Controlling Conflict from Interfering Long-term Memory Representations

2012 ◽  
Vol 24 (5) ◽  
pp. 1173-1190 ◽  
Author(s):  
Kerstin Jost ◽  
Patrick H. Khader ◽  
Peter Düsel ◽  
Franziska R. Richter ◽  
Kristina B. Rohde ◽  
...  
Keyword(s):  
Memory Retrieval ◽  
Memory Trace ◽  
Long Term Memory ◽  
Retrieval Cues ◽  
Domain Specific ◽  
Specific Memory ◽  
Memory Representations ◽  
Retrieval Interference ◽  
Relevant Material

Remembering is more than an activation of a memory trace. As retrieval cues are often not uniquely related to one specific memory, cognitive control should come into play to guide selective memory retrieval by focusing on relevant while ignoring irrelevant information. Here, we investigated, by means of EEG and fMRI, how the memory system deals with retrieval interference arising when retrieval cues are associated with two material types (faces and spatial positions), but only one is task-relevant. The topography of slow EEG potentials and the fMRI BOLD signal in posterior storage areas indicated that in such situations not only the relevant but also the irrelevant material becomes activated. This results in retrieval interference that triggers control processes mediated by the medial and lateral PFC, which are presumably involved in biasing target representations by boosting the task-relevant material. Moreover, memory-based conflict was found to be dissociable from response conflict that arises when the relevant and irrelevant materials imply different responses. The two types of conflict show different activations in the medial frontal cortex, supporting the claim of domain-specific prefrontal control systems.

scholarly journals Author Correction: Increasing neurogenesis refines hippocampal activity rejuvenating navigational learning strategies and contextual memory throughout life

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Gabriel Berdugo-Vega ◽  
Gonzalo Arias-Gil ◽  
Adrian López-Fernández ◽  
Benedetta Artegiani ◽  
Joanna M. Wasielewska ◽  
...  
Keyword(s):  
Learning Strategies ◽  
Contextual Memory ◽  
Hippocampal Activity ◽  
Navigational Learning
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