scholarly journals Systems consolidation, transformation and reorganization: Multiple Trace Theory, Trace Transformation Theory and their Competitors

2021 ◽  
Author(s):  
Morris Moscovitch ◽  
Asaf Gilboa
Keyword(s):  
Neural Mechanisms ◽  
Close Correspondence ◽  
Transformation Theory ◽  
Trace Theory ◽  
Systems Consolidation ◽  
Neural Representations ◽  
Memory Change ◽  
History Of ◽  
Proper Perspective ◽  
Multiple Trace Theory

We review the literature on systems consolidation by providing a brief history of the field to place the current research in proper perspective. We cover the literature on both humans and non-humans, which are highly related despite the differences in techniques and tasks that are used. We argue that understanding the interactions between hippocampus and neocortex (and other structures) that underlie systems consolidation, depend on appreciating the close correspondence between psychological and neural representations of memory, as postulated by Multiple Trace Theory and Trace Transformation Theory. We end by evaluating different theories of systems consolidation in light of the evidence we reviewed and suggest that the concept of systems consolidation, with its central concern with the time-limited role the hippocampus plays in memory, may have outlived its usefulness. We suggest replacing it with a program of research on the psychological processes and neural mechanisms that underlie changes in memory across the lifetime – a natural history of memory change.

scholarly journals Exploring the role of expectations and stimulus relevance on stimulus-specific neural representations and conscious report

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Erik L Meijs ◽  
Pim Mostert ◽  
Heleen A Slagter ◽  
Floris P de Lange ◽  
Simon van Gaal
Keyword(s):  
Attentional Blink ◽  
Neural Activity ◽  
Subjective Experience ◽  
Activity Patterns ◽  
Neural Mechanisms ◽  
Top Down ◽  
Neural Representations ◽  
Dependent Signal ◽  
Task Irrelevant

Abstract Subjective experience can be influenced by top-down factors, such as expectations and stimulus relevance. Recently, it has been shown that expectations can enhance the likelihood that a stimulus is consciously reported, but the neural mechanisms supporting this enhancement are still unclear. We manipulated stimulus expectations within the attentional blink (AB) paradigm using letters and combined visual psychophysics with magnetoencephalographic (MEG) recordings to investigate whether prior expectations may enhance conscious access by sharpening stimulus-specific neural representations. We further explored how stimulus-specific neural activity patterns are affected by the factors expectation, stimulus relevance and conscious report. First, we show that valid expectations about the identity of an upcoming stimulus increase the likelihood that it is consciously reported. Second, using a series of multivariate decoding analyses, we show that the identity of letters presented in and out of the AB can be reliably decoded from MEG data. Third, we show that early sensory stimulus-specific neural representations are similar for reported and missed target letters in the AB task (active report required) and an oddball task in which the letter was clearly presented but its identity was task-irrelevant. However, later sustained and stable stimulus-specific representations were uniquely observed when target letters were consciously reported (decision-dependent signal). Fourth, we show that global pre-stimulus neural activity biased perceptual decisions for a ‘seen’ response. Fifth and last, no evidence was obtained for the sharpening of sensory representations by top-down expectations. We discuss these findings in light of emerging models of perception and conscious report highlighting the role of expectations and stimulus relevance.

Para-Professionals in Mobility: Long-Term Implications

1976 ◽  
Vol 70 (8) ◽  
pp. 329-331
Author(s):  
William H. Jacobson
Keyword(s):  
Future Trends ◽  
Historical Trend ◽  
Orientation And Mobility ◽  
History Of ◽  
Proper Perspective

The role of the para-professional in the modern orientation and mobility program is discussed. A brief history of the mobility profession is recounted to give a proper perspective in which to view present and future trends. The para-professional is then compared with his professional counterpart, the certified orientation and mobility specialist. The attitudes, duties, and goals of the mobility specialist and his profession are explored in relationship to those of the para-professional. The author concludes that the profession is too young and the historical trend too contradictory to permit acceptance of para-professionals in the mobility program at this time.

scholarly journals Putative protective neural mechanisms in prereaders with a family history of dyslexia who subsequently develop typical reading skills

2020 ◽  
Vol 41 (10) ◽  
pp. 2827-2845
Author(s):  
Xi Yu ◽  
Jennifer Zuk ◽  
Meaghan V. Perdue ◽  
Ola Ozernov‐Palchik ◽  
Talia Raney ◽  
...  
Keyword(s):  
Family History ◽  
Reading Skills ◽  
Neural Mechanisms ◽  
History Of

scholarly journals Excitatory TMS Boosts Memory Representations

2018 ◽  
Author(s):  
Wei-Chun Wang ◽  
Erik A. Wing ◽  
David L.K. Murphy ◽  
Bruce M. Luber ◽  
Sarah H. Lisanby ◽  
...  
Keyword(s):  
Cognitive Enhancement ◽  
Functional Neuroimaging ◽  
Brain Activity ◽  
Neural Mechanisms ◽  
Temporal Memory ◽  
Memory Functioning ◽  
Neural Representations ◽  
Memory Representations ◽  
Science Investigations ◽  
Univariate Analyses

AbstractBrain stimulation technologies have seen increasing application in basic science investigations, specifically towards the goal of improving memory functioning. However, proposals concerning the neural mechanisms underlying cognitive enhancement often rely on simplified notions of excitation and, most applications examining the effects of transcranial magnetic stimulation (TMS) on functional neuroimaging measures have been limited to univariate analyses of brain activity. We present here analyses using representational similarity analysis (RSA) and encoding-retrieval similarity (ERS) analysis in order to quantify the effect of TMS on memory representations. To test whether an increase in local excitability in PFC can have measurable influences on upstream representations in earlier temporal memory regions, we compared 1Hz and 5Hz stimulation to the left dorsolateral PFC. We found that 10 minutes of 5Hz rTMS, relative to 1Hz, had multiple effects on neural representations: 1) greater RSA during both encoding and retrieval, 2) greater ERS across all items, and, critically, 3) increasing ERS in MTL with increasing univariate activity in DLPFC, and greater functional connectivity for hits than misses between these regions. These results provide the first evidence of rTMS enhancing semantic representations and strengthen the idea that rTMS may affect the reinstatement of previously experienced events in upstream regions.

scholarly journals Decoding the neural mechanisms of human tool use

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Jason P Gallivan ◽  
D Adam McLean ◽  
Kenneth F Valyear ◽  
Jody C Culham
Keyword(s):  
Tool Use ◽  
Neural Mechanisms ◽  
Primate Species ◽  
Classification Methods ◽  
Body Perception ◽  
Sensorimotor Processing ◽  
Neural Representations ◽  
Frontoparietal Cortex ◽  
Hierarchical Nature ◽  
The Brain

Sophisticated tool use is a defining characteristic of the primate species but how is it supported by the brain, particularly the human brain? Here we show, using functional MRI and pattern classification methods, that tool use is subserved by multiple distributed action-centred neural representations that are both shared with and distinct from those of the hand. In areas of frontoparietal cortex we found a common representation for planned hand- and tool-related actions. In contrast, in parietal and occipitotemporal regions implicated in hand actions and body perception we found that coding remained selectively linked to upcoming actions of the hand whereas in parietal and occipitotemporal regions implicated in tool-related processing the coding remained selectively linked to upcoming actions of the tool. The highly specialized and hierarchical nature of this coding suggests that hand- and tool-related actions are represented separately at earlier levels of sensorimotor processing before becoming integrated in frontoparietal cortex.

Modification des pressions intracristallines et intergranulaires des roches soumises aux variations de temperature

1961 ◽  
Vol S7-III (4) ◽  
pp. 338-344 ◽  
Author(s):  
Georges Deicha
Keyword(s):  
Small Temperature ◽  
Temperature Changes ◽  
History Of ◽  
Proper Perspective ◽  
Proper Interpretation ◽  
Tectonic Movements ◽  
Natural Means

Abstract Effects of variations of temperature on intracrystalline and intergranular pressures in rocks are reviewed, with particular stress on the importance of maintaining the several factors involved in proper perspective, in order that sequence of changes in a rock during its history may not be misconstrued and that undue importance is not assigned to a given factor merely because it has been investigated in detail while others have been investigated inadequately. Distinguishing between liquid and gaseous inclusions of mineralogic versus metallogenic periods is especially difficult. Proper interpretation of inclusions ruptured by natural means must be supplemented by painstaking care to recognize the ruptures resulting from artificial means such as those produced in preparation of petrographic specimens, blows of the geologic hammer , and during transportation of samples. Liquid CO<2) and other inclusions have been known to rupture from small temperature changes. Water in inclusions in mineral grains can influence the geochemical constitution of water imprisoned in the sediments at time of deposition. Tectonic movements may rupture inclusions, and thereby influence the geophysical history of rocks.

The Perception of Time

2006 ◽  
Author(s):  
Michel Treisman
Keyword(s):  
Nervous System ◽  
Experimental Evidence ◽  
Physical World ◽  
Neural Mechanisms ◽  
Temporal Information ◽  
Close Correspondence ◽  
Psychological Model ◽  
Secondary Quality ◽  
Quality Distinction ◽  
Perception Of Time

This chapter aims to present a psychological model of how people perceive time, and to explain some experimental evidence supporting it. It suggests that the apparently close correspondence between the spatiotemporal structures of the perceived world and of the physical world, in contrast to the complex and controversial relation between, for example, perceived colour and light, lies at the root of the primary quality/secondary quality distinction. It also examines the neural mechanisms by which people keep track of time. The answer to this question is a model in which the nervous system itself produces temporal information, in the form of a ‘pacemaker’ or pacemakers that emit pulses at regular characteristic intervals; the model also includes a ‘calibration unit’ to allow for flexibility in the accuracy of timing. The chapter ends by surveying the experimental evidence for this model, including EEG studies.

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