scholarly journals Biased Competition during Long-term Memory Formation

2016 ◽  
Vol 28 (1) ◽  
pp. 187-197 ◽  
Author(s):  
J. Benjamin Hutchinson ◽  
Sarah S. Pak ◽  
Nicholas B. Turk-Browne

A key task for the brain is to determine which pieces of information are worth storing in memory. To build a more complete representation of the environment, memory systems may prioritize new information that has not already been stored. Here, we propose a mechanism that supports this preferential encoding of new information, whereby prior experience attenuates neural activity for old information that is competing for processing. We evaluated this hypothesis with fMRI by presenting a series of novel stimuli concurrently with repeated stimuli at different spatial locations in Experiment 1 and from different visual categories (i.e., faces and scenes) in Experiment 2. Subsequent memory for the novel stimuli could be predicted from the reduction in activity in ventral temporal cortex for the accompanying repeated stimuli. This relationship was eliminated in control conditions where the competition during encoding came from another novel stimulus. These findings reveal how prior experience adaptively guides learning toward new aspects of the environment.

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
Mona Helmchen

AbstractIn the present article and in a theoretical frame based in cognitive linguistics, we will justify and analyse some of the translational processes that have taken place during the translation of the novel “La Tesis de Nancy” (1962). The human being constantly perceives a multitude of impressions which operate as mental impulses and which activate parts of the long-term memory to facilitate the understanding of new information. Apart from the development of mental spaces, the metaphorical thinking plays an important role in the creation of meaning and in the understanding of reality. A professional translator has to consider that an awareness of such processes can be an inspirational source for a creative and functional translation.


2019 ◽  
Vol 5 (4) ◽  
pp. eaav1695 ◽  
Author(s):  
L. Himmer ◽  
M. Schönauer ◽  
D. P. J. Heib ◽  
M. Schabus ◽  
S. Gais

After encoding, memories undergo a transitional process termed systems memory consolidation. It allows fast acquisition of new information by the hippocampus, as well as stable storage in neocortical long-term networks, where memory is protected from interference. Whereas this process is generally thought to occur slowly over time and sleep, we recently found a rapid memory systems transition from hippocampus to posterior parietal cortex (PPC) that occurs over repeated rehearsal within one study session. Here, we use fMRI to demonstrate that this transition is stabilized over sleep, whereas wakefulness leads to a reset to naïve responses, such as observed during early encoding. The role of sleep therefore seems to go beyond providing additional rehearsal through memory trace reactivation, as previously thought. We conclude that repeated study induces systems consolidation, while sleep ensures that these transformations become stable and long lasting. Thus, sleep and repeated rehearsal jointly contribute to long-term memory consolidation.


2021 ◽  
Vol 226 (4) ◽  
pp. 989-1006
Author(s):  
Ilenia Salsano ◽  
Valerio Santangelo ◽  
Emiliano Macaluso

AbstractPrevious studies demonstrated that long-term memory related to object-position in natural scenes guides visuo-spatial attention during subsequent search. Memory-guided attention has been associated with the activation of memory regions (the medial-temporal cortex) and with the fronto-parietal attention network. Notably, these circuits represent external locations with different frames of reference: egocentric (i.e., eyes/head-centered) in the dorsal attention network vs. allocentric (i.e., world/scene-centered) in the medial temporal cortex. Here we used behavioral measures and fMRI to assess the contribution of egocentric and allocentric spatial information during memory-guided attention. At encoding, participants were presented with real-world scenes and asked to search for and memorize the location of a high-contrast target superimposed in half of the scenes. At retrieval, participants viewed again the same scenes, now all including a low-contrast target. In scenes that included the target at encoding, the target was presented at the same scene-location. Critically, scenes were now shown either from the same or different viewpoint compared with encoding. This resulted in a memory-by-view design (target seen/unseen x same/different view), which allowed us teasing apart the role of allocentric vs. egocentric signals during memory-guided attention. Retrieval-related results showed greater search-accuracy for seen than unseen targets, both in the same and different views, indicating that memory contributes to visual search notwithstanding perspective changes. This view-change independent effect was associated with the activation of the left lateral intra-parietal sulcus. Our results demonstrate that this parietal region mediates memory-guided attention by taking into account allocentric/scene-centered information about the objects' position in the external world.


2013 ◽  
Vol 25 (7) ◽  
pp. 1111-1121 ◽  
Author(s):  
Kristjan Kalm ◽  
Matthew H. Davis ◽  
Dennis Norris

Much of what we need to remember consists of sequences of stimuli, experiences, or events. Repeated presentation of a specific sequence establishes a more stable long-term memory, as shown by increased recall accuracy over successive trials of an STM task. Here we used fMRI to study the neural mechanisms that underlie sequence learning in the auditory–verbal domain. Specifically, we track the emergence of neural representations of sequences over the course of learning using multivariate pattern analysis. For this purpose, we use a serial recall task, in which participants have to recall overlapping sequences of letter names, with some of those sequences being repeated and hence learned over the course of the experiment. We show that voxels in the hippocampus come to encode the identity of specific repeated sequences although the letter names were common to all sequences in the experiment. These changes could have not been caused by changes in overall level of activity or to fMRI signal-to-noise ratios. Hence, the present results go beyond conventional univariate fMRI methods in showing a critical contribution of medial-temporal lobe memory systems to establishing long-term representations of verbal sequences.


2018 ◽  
Author(s):  
Angelica Staniloiu ◽  
Hans Markowitsch

Dissociative disorders are heterogeneous with respect to clinical features, course, antecedents and treatment. Among them, dissociative amnesia occupies a special place, at times encroaching on the borders between neurology and psychiatry. Herein we describe dissociative amnesia according to the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders and outline data on its epidemiology, neurobiology, neuroimaging, clinical and differential diagnosis, neuropsychology, comorbidities, prognosis, treatment and rehabilitation. To enable a neuroscientific approach to its diagnosis, we outline the memory division into short-term and long-term memory, elaborating on the content-based classification of the long-term memory systems. Dissociative amnesia most commonly manifests itself in its retrograde variants (including dissociative fugue), but anterograde variants can also occur. Dissociative amnesia may be overlooked when it occurs on a background of mixed antecedents and comorbidities. Comprehensive neuropsychological assessment – including tests tapping on all memory systems and symptom validity tests – is still insufficiently integrated in the clinical practice, although it could aid in securing an accurate diagnosis, especially in cases with mixed antecedents or concomitant forensic or litigation backgrounds. Presently there is a paucity of treatment and rehabilitation methods for dissociative amnesia. Developing research evidence-based consensus guidelines for diagnosis and treatment is an essential goal. This review contains 6 figures, 7 tables, and 60 references. Key Words : consciousness, episodic-autobiographical memory, mnestic block syndrome, neuroimaging, serial-parallel-independent model, personal identity, stressful life events, malingering, trauma, feigning


2020 ◽  
pp. 311-332
Author(s):  
Nicole Hakim ◽  
Edward Awh ◽  
Edward K. Vogel

Visual working memory allows us to maintain information in mind for use in ongoing cognition. Research on visual working memory often characterizes it within the context of its interaction with long-term memory (LTM). These embedded-processes models describe memory representations as existing in three potential states: inactivated LTM, including all representations stored in LTM; activated LTM, latent representations that can quickly be brought into an active state due to contextual priming or recency; and the focus of attention, an active but sharply limited state in which only a small number of items can be represented simultaneously. This chapter extends the embedded-processes framework of working memory. It proposes that working memory should be defined operationally based on neural activity. By defining working memory in this way, the important theoretical distinction between working memory and LTM is maintained, while still acknowledging that they operate together. It is additionally proposed that active working memory should be further subdivided into at least two subcomponent processes that index item-based storage and currently prioritized spatial locations. This fractionation of working memory is based on recent research that has found that the maintenance of information distinctly relies on item-based representations as well as prioritization of spatial locations. It is hoped that this updated framework of the definition of working memory within the embedded-processes model provides further traction for understanding how we maintain information in mind.


2013 ◽  
Vol 18 (2) ◽  
pp. 190-200
Author(s):  
Christopher J. Keyes

Although the pedagogy of music technology more closely resembles that of other academic subjects, the teaching of electroacoustic composition involves a significant degree of creativity, and thus relies on different creativity-specific parts of the brain and memory systems (Lehmann 2007). This paper reviews recent neuroscientific research that may assist differentiation between effective pedagogical approaches of these two subjects where knowledge is stored in separate, discrete and sometimes competing long-term memory locations (Cotterill 2001). It argues that, because of these differences, the learning of music technology and electroacoustic composition is best kept separate, at least in the beginning stages. These points are underscored by an example of a demonstrably failed pedagogical model for teaching electroacoustic composition contrasted with a subsequent highly successful model employed in the same university music programme; an experience that may translate well to other learning environments.


1992 ◽  
Vol 12 (3) ◽  
pp. 353-358 ◽  
Author(s):  
Ferruccio Fazio ◽  
Daniela Perani ◽  
Maria Carla Gilardi ◽  
Fabio Colombo ◽  
Stefano F. Cappa ◽  
...  

Human amnesia is a clinical syndrome exhibiting the failure to recall past events and to learn new information. Its “pure” form, characterized by a selective impairment of long-term memory without any disorder of general intelligence or other cognitive functions, has been associated with lesions localized within Papez's circuit and some connected areas. Thus, amnesia could be due to a functional disconnection between components of this or other neural structures involved in long-term learning and retention. To test this hypothesis, we measured regional cerebral metabolism with 2-[18F]fluoro-2-deoxy-d-glucose ([18F]FDG) and positron emission tomography (PET) in 11 patients with “pure” amnesia. A significant bilateral reduction in metabolism in a number of interconnected cerebral regions (hippocampal formation, thalamus, cingulate gyrus, and frontal basal cortex) was found in the amnesic patients in comparison with normal controls. The metabolic impairment did not correspond to alterations in structural anatomy as assessed by magnetic resonance imaging (MRI). These results are the first in vivo evidence for the role of a functional network as a basis of human memory.


2011 ◽  
Vol 1423 ◽  
pp. 30-40 ◽  
Author(s):  
Hironori Kasahara ◽  
Daigo Takeuchi ◽  
Masaki Takeda ◽  
Toshiyuki Hirabayashi

2018 ◽  
Vol 72 (5) ◽  
pp. 1005-1028 ◽  
Author(s):  
Franziska Orscheschek ◽  
Tilo Strobach ◽  
Torsten Schubert ◽  
Timothy Rickard

There is evidence in the literature that two retrievals from long-term memory cannot occur in parallel. To date, however, that work has explored only the case of two retrievals from newly acquired episodic memory. These studies demonstrated a retrieval bottleneck even after dual-retrieval practice. That retrieval bottleneck may be a global property of long-term memory retrieval, or it may apply only to the case of two retrievals from episodic memory. In the current experiments, we explored whether that apparent dual-retrieval bottleneck applies to the case of one retrieval from episodic memory and one retrieval from highly overlearned semantic memory. Across three experiments, subjects learned to retrieve a left or right keypress response form a set of 14 unique word cues (e.g., black—right keypress). In addition, they learned a verbal response which involved retrieving the antonym of the presented cue (e.g., black—“white”). In the dual-retrieval condition, subjects had to retrieve both the keypress response and the antonym word. The results suggest that the retrieval bottleneck is superordinate to specific long-term memory systems and holds across different memory components. In addition, the results support the assumption of a cue-level response chunking account of learned retrieval parallelism.


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