scholarly journals Interfering with a memory without erasing its trace

2019 ◽  
Author(s):  
Gesa Lange ◽  
Mario Senden ◽  
Alexandra Radermacher ◽  
Peter De Weerd
Keyword(s):  
Discrimination Task ◽  
Orientation Discrimination ◽  
Memory Mechanism ◽  
Open Questions ◽  
Model Predictions ◽  
Task Training ◽  
Human Participants ◽  
Similar Task ◽  
Training Protocol

AbstractPrevious research has shown that performance of a novice skill can be easily interfered with by subsequent training of another skill. We address the open questions whether extensively trained skills show the same vulnerability to interference as novice skills and which memory mechanism regulates interference between expert skills. We developed a recurrent neural network model of V1 able to learn from feedback experienced over the course of a long-term orientation discrimination experiment. After first exposing the model to one discrimination task for 3480 consecutive trials, we assessed how its performance was affected by subsequent training in a second, similar task. Training the second task strongly interfered with the first (highly trained) discrimination skill. The magnitude of interference depended on the relative amounts of training devoted to the different tasks. We used these and other model outcomes as predictions for a perceptual learning experiment in which human participants underwent the same training protocol as our model. Specifically, over the course of three months participants underwent baseline training in one orientation discrimination task for 15 sessions before being trained for 15 sessions on a similar task and finally undergoing another 15 sessions of training on the first task (to assess interference). Across all conditions, the pattern of interference observed empirically closely matched model predictions. According to our model, behavioral interference can be explained by antagonistic changes in neuronal tuning induced by the two tasks. Remarkably, this did not stem from erasing connections due to earlier learning but rather from a reweighting of lateral inhibition.

Human Short-Long Term Cognitive Memory Mechanism for Visual Monitoring in IoT-Assisted Smart Cities

2021 ◽  
pp. 1-1
Author(s):  
Shuai Wang ◽  
Xinyu Liu ◽  
Shuai Liu ◽  
Khan Muhammad ◽  
Ali Asghar Heidari ◽  
...  
Keyword(s):  
Smart Cities ◽  
Visual Monitoring ◽  
Memory Mechanism ◽  
Cognitive Memory

scholarly journals Investigations of long-term trends in the ionosphere with world-wide ionosonde observations*

2005 ◽  
Vol 2 ◽  
pp. 253-258 ◽  
Author(s):  
J. Bremer
Keyword(s):  
Data Series ◽  
Model Calculations ◽  
Maximum Electron Density ◽  
Model Predictions ◽  
Density Values ◽  
Long Term Trends ◽  
Experimental Values ◽  
The Individual ◽  
Global Mean

Abstract. Basing on model calculations by Roble and Dickinson (1989) for an increasing content of atmospheric greenhouse gases in the Earth’s atmosphere Rishbeth (1990) predicted a lowering of the ionospheric F2- and E-regions. Later Rishbeth and Roble (1992) also predicted characteristic longterm changes of the maximum electron density values of the ionospheric E-, F1-, and F2-layers. Long-term observations at more than 100 ionosonde stations have been analyzed to test these model predictions. In the E- and F1-layers the derived experimental results agree reasonably with the model trends (lowering of h'E and increase of ƒoE and ƒoF1, in the E-layer the experimental values are however markedly stronger than the model data). In the ionospheric F2-region the variability of the trends derived at the different individual stations for hmF2 as well as ƒoF2 values is too large to estimate reasonable global mean trends. The reason of the large differences between the individual trends is not quite clear. Strong dynamical effects may play an important role in the F2-region. But also inhomogeneous data series due to technical changes as well as changes in the evaluation algorithms used during the long observation periods may influence the trend analyses.

scholarly journals Exploring Implicit and Explicit Attitudes of Employees’ Authentic Organizational Loyalty

2021 ◽  
Vol 12 ◽  
Author(s):  
Ji-Woong Hong ◽  
Ah Jeong Hong ◽  
Sang Rak Kim
Keyword(s):  
Implicit Association Test ◽  
Organizational Growth ◽  
Organizational Participation ◽  
Explicit Attitudes ◽  
Organizational Loyalty ◽  
Open Questions ◽  
Target Company ◽  
Implicit And Explicit ◽  
Implicit And Explicit Attitudes

The purpose of this study was to develop the OL-IAT (Organizational Loyalty – Implicit Association Test), an IAT tool that measures implicit attitudes toward organizational loyalty, and to verify its predictive validity. In total, 15 respondents were randomly selected from among the employees of P Company. The respondents were then asked open questions about the image they held of the target company. Based on their responses, a list of words was compiled for use on the OL-IAT. Evaluation categories, either like-dislike or positive-negative, were developed for this test based on the approach-avoidance words proposed by Ostafin and Palfai (2006). The OL-IAT was then administered to 127 employees of Company P, and self-reporting measures were also devised to measure explicit attitudes. A survey of whether the implicit attitude toward organizational loyalty was consistent with the explicit attitude showed that there was no significant correlation, and the attitude inconsistency was evident in the responses. When differences in rank were accounted for, organizational loyalty attitudes were consistent at the manager level, and organizational participation attitudes were consistent at the manager and general staff levels. This study will aid in the development of effective measures of organizational loyalty and accelerate interventions to increase it, which in turn will positively impact long-term organizational growth.

scholarly journals Patients with Schizophrenia Remember that an Event has Occurred, but not When

1996 ◽  
Vol 168 (4) ◽  
pp. 427-431 ◽  
Author(s):  
Lydia Rizzo ◽  
Jean-Marie Danion ◽  
Martial Van Der Linden ◽  
Danielle Grangé
Keyword(s):  
Memory Impairment ◽  
Discrimination Task ◽  
Contextual Information ◽  
Normal Subjects ◽  
Memory Deficit ◽  
Temporal Context ◽  
Context Memory

BackgroundThe context memory deficit hypothesis of schizophrenia postulates that the long-term deficit associated with this disorder is related to a memory impairment for contextual information.MethodTo test this hypothesis, memory for temporal context was assessed in 33 patients with schizophrenia and 33 normal subjects, using a recency discrimination task.ResultsWhereas patients were able to recall and recognise target items, they were unable to recognise from among the target items those which had been most recently learned.ConclusionsSchizophrenia is associated with a temporal context memory deficit.

scholarly journals Long-term potentiation: outstanding questions and attempted synthesis

2003 ◽  
Vol 358 (1432) ◽  
pp. 829-842 ◽  
Author(s):  
John Lisman
Keyword(s):  
Low Frequency ◽  
Long Term Potentiation ◽  
Variable Number ◽  
High Frequency Stimulation ◽  
Memory Mechanism ◽  
Post Process ◽  
Term Potentiation ◽  
Contradictory Evidence ◽  
Hippocampal Networks

This article attempts an overview of the mechanism of NMDAR-dependent long-term potentiation (LTP) and its role in hippocampal networks. Efforts are made to integrate information, often in speculative ways, and to identify unresolved issues about the induction, expression and molecular storage processes. The pre/post debate about LTP expression has been particularly difficult to resolve. The following hypothesis attempts to reconcile the available physiological evidence as well as anatomical evidence that LTP increases synapse size. It is proposed that synapses are composed of a variable number of trans-synaptic modules, each having presynaptic release sites and a postsynaptic structure that can be AMPAfied by the addition of a hyperslot assembly that anchors 10-20 AMPA channels. According to a newly developed view of transmission, the quantal response is generated by AMPA channels near the site of vesicle release and so will depend on whether the module where release occurs has been AMPAfied. LTP expression may involve two structurally mediated processes: (i) the AMPAfication of existing modules by addition of hyperslot assemblies: this is a purely postsynaptic process and produces an increase in the probability of an AMPA response, with no change in the NMDA component; and (ii) the addition of new modules: this is a structurally coordinated pre/post process that leads to LTP-induced synapse enlargement and potentiation of the NMDA component owing to an increase in the number of release sites (the number of NMDA channels is assumed to be fixed). The protocol used for LTP induction appears to affect the proportion of these two processes; pairing protocols that involve low-frequency presynaptic stimulation induce only AMPAfication, making LTP purely postsynaptic, whereas high-frequency stimulation evokes both processes, giving rise to a presynaptic component. This model is capable of reconciling much of the seemingly contradictory evidence in the pre/post debate. The structural nature of the postulated changes is relevant to a second debate: whether a CaMKII switch or protein-dependent structural change is the molecular memory mechanism. A possible reconciliation is that a reversible CaMKII switch controls the construction of modules and hyperslot assemblies from newly synthesized proteins.

scholarly journals The Medial Temporal Lobe Is Critical for Spatial Relational Perception

2020 ◽  
Vol 32 (9) ◽  
pp. 1780-1795 ◽  
Author(s):  
Nicholas A. Ruiz ◽  
Michael R. Meager ◽  
Sachin Agarwal ◽  
Mariam Aly
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Critical Role ◽  
Long Term Memory ◽  
Term Memory ◽  
Cognitive Domains ◽  
Attention Tasks ◽  
Human Participants ◽  
Attention And Perception

The medial temporal lobe (MTL) is traditionally considered to be a system that is specialized for long-term memory. Recent work has challenged this notion by demonstrating that this region can contribute to many domains of cognition beyond long-term memory, including perception and attention. One potential reason why the MTL (and hippocampus specifically) contributes broadly to cognition is that it contains relational representations—representations of multidimensional features of experience and their unique relationship to one another—that are useful in many different cognitive domains. Here, we explore the hypothesis that the hippocampus/MTL plays a critical role in attention and perception via relational representations. We compared human participants with MTL damage to healthy age- and education-matched individuals on attention tasks that varied in relational processing demands. On each trial, participants viewed two images (rooms with paintings). On “similar room” trials, they judged whether the rooms had the same spatial layout from a different perspective. On “similar art” trials, they judged whether the paintings could have been painted by the same artist. On “identical” trials, participants simply had to detect identical paintings or rooms. MTL lesion patients were significantly and selectively impaired on the similar room task. This work provides further evidence that the hippocampus/MTL plays a ubiquitous role in cognition by virtue of its relational and spatial representations and highlights its important contributions to rapid perceptual processes that benefit from attention.

scholarly journals Investigating the Effects of tDCS on Visual Orientation Discrimination Task Performance: “the Possible Influence of Placebo”

2019 ◽  
Vol 4 (3) ◽  
pp. 235-249
Author(s):  
A. Bin Dawood ◽  
A. Dickinson ◽  
A. Aytemur ◽  
C. Howarth ◽  
E. Milne ◽  
...  
Keyword(s):  
Placebo Effect ◽  
Discrimination Task ◽  
Low Cost ◽  
Cortical Inhibition ◽  
Orientation Discrimination ◽  
Visual Orientation ◽  
Non Invasive ◽  
Clear Link ◽  
Cortical Modulation ◽  
Improved Performance

Abstract The non-invasive neuromodulation technique tDCS offers the promise of a low-cost tool for both research and clinical applications in psychology, psychiatry, and neuroscience. However, findings regarding its efficacy are often equivocal. A key issue is that the clinical and cognitive applications studied are often complex and thus effects of tDCS are difficult to predict given its known effects on the basic underlying neurophysiology, namely alterations in cortical inhibition-excitation balance. As such, it may be beneficial to assess the effects of tDCS in tasks whose performance has a clear link to cortical inhibition-excitation balance such as the visual orientation discrimination task (ODT). In prior studies in our laboratory, no practice effects were found during 2 consecutive runs of the ODT, thus in the current investigation, to examine the effects of tDCS, subjects received 10 min of 2 mA occipital tDCS (sham, anode, cathode) between a first and second run of ODT. Surprisingly, subjects’ performance significantly improved in the second run of ODT compared to the first one regardless of the tDCS stimulation type they received (anodal, cathodal, or sham-tDCS). Possible causes for such an improvement could have been due to either a generic “placebo” effect of tDCS (as all subjects received some form of tDCS) or an increased delay period between the two runs of ODT of the current study compared to our previous work (10-min duration required to administer tDCS as opposed to ~ 2 min in previous studies as a “break”). As such, we tested these two possibilities with a subsequent experiment in which subjects received 2-min or 10-min delay between the 2 runs (with no tDCS) or 10 min of sham-tDCS. Only sham-tDCS resulted in improved performance thus these data add to a growing literature suggesting that tDCS has powerful placebo effect that may occur even in the absence of active cortical modulation.

Responses of monkey inferior temporal neurons to luminance-, motion-, and texture-defined gratings

1995 ◽  
Vol 73 (4) ◽  
pp. 1341-1354 ◽  
Author(s):  
G. Sary ◽  
R. Vogels ◽  
G. Kovacs ◽  
G. A. Orban
Keyword(s):  
Visual Perception ◽  
Relative Motion ◽  
Discrimination Task ◽  
Stimulus Presentation ◽  
Response Strength ◽  
The Other ◽  
Orientation Discrimination ◽  
Macaque Monkeys ◽  
Tuning Width ◽  
Visual Cortical

1. We recorded from neurons responsive to gratings in the inferior temporal (IT) cortices of macaque monkeys. One of the monkeys performed an orientation discrimination task; the other maintained fixation during stimulus presentation. Stimuli consisted of gratings based on discontinuities in luminance, relative motion, and texture. 2. IT cells responded well to gratings defined solely by relative motion, implying either direct or indirect motion input into IT, an area that is part of the ventral visual cortical pathway. 3. Response strength in general did not depend on the cue used to define the gratings. Latency values observed for the two static grating types (luminance- and texture-defined gratings) were similar, but significantly shorter than those measured for the kinetic gratings. 4. Stimulus orientation had a significant effect in 27%, 27%, and 9% of the cells tested with luminance-, kinetic-, and texture-defined gratings, respectively. 5. Only a small proportion of cells were orientation sensitive for more than one defining cue. The average preferred orientation for luminance and kinetic gratings matched; the tuning width was similar for the two cues. 6. Our results indicate that IT cells may contribute to cue-invariant coding of boundaries and edges. We discuss the relevance of these results to visual perception.

Reduced hyperpnea-induced bronchospasm following repeated cold air challenge

1986 ◽  
Vol 61 (1) ◽  
pp. 210-214 ◽  
Author(s):  
F. Haas ◽  
N. Levin ◽  
S. Pasierski ◽  
M. Bishop ◽  
K. Axen
Keyword(s):  
Base Line ◽  
Maximum Heart Rate ◽  
Cold Air ◽  
Asthma Symptoms ◽  
Rest Periods ◽  
Before And After ◽  
Exercise Induced ◽  
Inflammatory Changes ◽  
Training Protocol

This study assessed reduction in expiratory function in 12 asthmatic subjects both after 5 min of cold air provocation (CAP) with dry air conditioned to approximately 0 degrees C and after exercise (to 85% of predicted maximum heart rate) while breathing ambient room air (approximately 21 degrees C and 40% relative humidity). These assessments were done both before and after the following training protocol. Three 5-min periods of isocapnic cold air hyperpnea separated by 5-min rest periods were performed breathing 0 degrees to -10 degrees C air, for 36 sessions over 12 wk. As expected, pretraining expiratory function was significantly reduced (P less than 0.001) after both CAP and exercise. The posttraining reduction in expiratory function after CAP and exercise, however, was significantly less pronounced (largest P less than 0.05). These data support our hypothesis that repeated bouts of cold air challenge result in airway acclimatization to cold air and consequent decrease in exercise-induced bronchospasm. Acclimatization may result directly either by habituation of the airways or by vasodilation leading to increased bronchial blood flow and consequent reduced airway cooling. An unanticipated finding, though, is that repeated cold air challenge may also cause long-term inflammatory changes in the airways. A significant percentage of subjects experienced reduced base-line pulmonary function and overall exacerbation of asthma symptoms during the training period.

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