High Interference Conditions Research Articles

The Infralimbic, but not the Prelimbic Cortex is needed for a Complex Olfactory Memory Task.

The medial prefrontal cortex (mPFC) plays a key role in memory and behavioral flexibility, and a growing body of evidence suggests that the prelimbic (PL) and infralimbic (IL) subregions contribute differently to these processes. Studies of fear conditioning and goal-directed learning suggest that the PL promotes behavioral responses and memory retrieval, while the IL inhibits them. Other studies have shown that the mPFC is engaged under conditions of high interference. This raises the possibility that the PL and IL play differing roles in resolving interference. To examine this, we first used chemogenetics (DREADDs) to suppress mPFC neuronal activity and tested subjects on a conditional discrimination task known to be sensitive to muscimol inactivation. After confirming the effectiveness of the DREADD procedures, we conducted a second experiment to examine the PL and IL roles in a high interference memory task. We trained rats on two consecutive sets of conflicting odor discrimination problems, A and B, followed by test sessions involving a mid-session switch between the problem sets. Controls repeatedly performed worse on Set A, suggesting that learning Set B inhibited the rats' ability to retrieve Set A memories (i.e. retroactive interference). PL inactivation rats performed similarly to controls. However, IL inactivation rats did not show this effect, suggesting that the IL plays a critical role in suppressing the retrieval of previously acquired memories that may interfere with retrieval of more recent memories. These results suggest that the IL plays a critical role in memory control processes needed for resolving interference.

Effects of video game immersion and task interference on cognitive performance: a study on immediate and delayed recall and recognition accuracy.

This study investigates the cognitive impacts of video game immersion and task interference on immediate and delayed recall as well as recognition tasks. We enrolled 160 subjects aged 18 to 29, who were regular players of "shoot-em-up" video games for at least 3 years. Participants were assigned to one of three experimental groups or a control group. The experimental conditions varied in the timing and type of tasks: the first group performed a video game session between recall tasks, the second group multitasked with video games and recall tasks simultaneously, and the third group engaged in task switching from video games to recall tasks. Using the Rey Auditory Verbal Learning Test, we measured the effects of these conditions on cognitive performance, focusing on error types and recall accuracy. Results indicated that multitasking and task switching significantly affected the subjects' performance, with notable decrements in recall and recognition accuracy in conditions of high task interference. The study highlights the cognitive costs associated with multitasking in immersive digital games and provides insights into how task similarity and interference might increase error rates and affect memory performance.

Storage interference in working memory cannot be removed by attention

In the present study, we examined the hypothesis that the storage interference in working memory can be removed by attention. A dual-task paradigm was employed in Experiment 1 and 2, in which participants performed a color memory task and an RSVP letter detection task concurrently. The cognitive load of the RSVP letter detection task and the storage interference caused by the RSVP letter detection task was manipulated independently. That is, the produced storage-interference difference between the low and high interference conditions was comparable between the low and high cognitive load conditions, whereas the available attentional resources were different under the two cognitive load conditions. Since there were more attentional resources in the low load condition, the removal hypothesis predicts that differences in recall performance between the low and high interference conditions should be larger in high load than in low load, i.e., there would be an interaction between load and interference. However, the results of the two experiments did not show such an interaction. In Experiment 3, we manipulated the time available for the removal mechanism to work while inducing both the storage interference and processing interference. The results showed no sign of interference removal. Thus, the present results provided solid evidence to challenge the removal hypothesis.

Environmental enrichment in middle age rats improves spatial and object memory discrimination deficits.

Changes in memory performance are one of the main symptoms of normal aging. The storage of similar experiences as different memories (ie. behavioral pattern separation), becomes less efficient as aging progresses. Studies have focused on hippocampus dependent spatial memories and their role in the aging related deficits in behavioral pattern separation (BPS) by targeting high similarity interference conditions. However, parahippocampal cortices such as the perirhinal cortex are also particularly vulnerable to aging. Middle age is thought to be the stage where mild mnemonic deficits begin to emerge. Therefore, a better understanding of the timing of the spatial and object domain memory impairment could shed light over how plasticity changes in the parahipocampal-hippocampal system affects mnemonic function in early aging. In the present work, we compared the performance of young and middle-aged rats in both spatial (spontaneous location recognition) and non-spatial (spontaneous object recognition) behavioral pattern separation tasks to understand the comparative progression of these deficits from early stages of aging. Moreover, we explored the impact of environmental enrichment (EE) as an intervention with important translational value. Although a bulk of studies have examined the contribution of EE for preventing age related memory decline in diverse cognitive domains, there is limited knowledge of how this intervention could specifically impact on BPS function in middle-aged animals. Here we evaluate the effects of EE as modulator of BPS, and its ability to revert the deficits caused by normal aging at early stages. We reveal a domain-dependent impairment in behavioral pattern separation in middle-aged rats, with spatial memories affected independently of the similarity of the experiences and object memories only affected when the stimuli are similar, an effect that could be linked to the higher interference seen in this group. Moreover, we found that EE significantly enhanced behavioral performance in middle-aged rats in the spatial and object domain, and this improvement is specific of the high similarity load condition. In conclusion, these results suggest that memory is differentially affected by aging in the object and spatial domains, but that BPS function is responsive to an EE intervention in a multidomain manner.

On the Required Radio Resources for Ultra-Reliable Communication in Highly Interfered Scenarios

Future wireless systems are expected to support mission-critical services demanding higher and higher reliability. In this letter, we dimension the radio resources needed to achieve a given failure probability target for ultra-reliable wireless systems in high interference conditions, assuming a protocol with frequency hopping combined with packet repetitions. We resort to packet erasure channel models and derive the minimum amount of resource units in the case of receiver with and without collision resolution capability, as well as the number of packet repetitions needed for achieving the failure probability target. Analytical results are numerically validated, and can be used as benchmark for realistic system simulations.

Phase separation of competing memories along the human hippocampal theta rhythm.

Competition between overlapping memories is considered one of the major causes of forgetting, and it is still unknown how the human brain resolves such mnemonic conflict. In the present magnetoencephalography (MEG) study, we empirically tested a computational model that leverages an oscillating inhibition algorithm to minimise overlap between memories. We used a proactive interference task, where a reminder word could be associated with either a single image (non-competitive condition) or two competing images, and participants were asked to always recall the most recently learned word-image association. Time-resolved pattern classifiers were trained to detect the reactivated content of target and competitor memories from MEG sensor patterns, and the timing of these neural reactivations was analysed relative to the phase of the dominant hippocampal 3 Hz theta oscillation. In line with our pre-registered hypotheses, target and competitor reactivations locked to different phases of the hippocampal theta rhythm after several repeated recalls. Participants who behaviourally experienced lower levels of interference also showed larger phase separation between the two overlapping memories. The findings provide evidence that the temporal segregation of memories, orchestrated by slow oscillations, plays a functional role in resolving mnemonic competition by separating and prioritising relevant memories under conditions of high interference.

The Creative Knife: Does Interference Dull the Edge of Creativity Effectiveness?

It is no secret that creativity is an important component of advertising. It can enhance attention, facilitate recall, and drive emotional responses. However, there is continued opportunity to explore the boundary conditions regarding creativity’s ability to break though clutter. This article looks at whether two types of interference—external interference and competitive interference—limit creativity’s ability to enhance recall. We test this across three studies investigating the effects of these types of interference on individuals’ ability to recall creative ads and brands. The first experiment tested external interference using digitally manipulated print ads and three external music conditions. The second experiment tested competitive interference through TV ads. A third study extended the second study by holding creativity constant within the interference conditions. Results indicate that creativity does indeed facilitate recall under limited interference. However, this effect is lost under conditions of high interference, implying that creativity can be dulled and lost in the noise. We find these effects under both immediate and one-week-delay recall conditions. These findings are important for researchers and managers as the positive impact of creativity may not be realized under conditions of high interference but may certainly be fully realized in conditions of low or moderate interference.

Prefrontal Cortex Activation During Motor Sequence Learning Under Interleaved and Repetitive Practice: A Two-Channel Near-Infrared Spectroscopy Study.

Training under high interference conditions through interleaved practice (IP) results in performance suppression during training but enhances long-term performance relative to repetitive practice (RP) involving low interference. Previous neuroimaging work addressing this contextual interference effect of motor learning has relied heavily on the blood-oxygen-level-dependent (BOLD) response using functional magnetic resonance imaging (fMRI) methodology resulting in mixed reports of prefrontal cortex (PFC) recruitment under IP and RP conditions. We sought to clarify these equivocal findings by imaging bilateral PFC recruitment using functional near-infrared spectroscopy (fNIRS) while discrete key pressing sequences were trained under IP and RP schedules and subsequently tested following a 24-h delay. An advantage of fNIRS over the fMRI BOLD response is that the former measures oxygenated and deoxygenated hemoglobin changes independently allowing for assessment of cortical hemodynamics even when there is neurovascular decoupling. Despite slower sequence performance durations under IP, bilateral PFC oxygenated and deoxygenated hemoglobin values did not differ between practice conditions. During test, however, slower performance from those previously trained under RP coincided with hemispheric asymmetry in PFC recruitment. Specifically, following RP, test deoxygenated hemoglobin values were significantly lower in the right PFC. The present findings contrast with previous behavioral demonstrations of increased cognitive demand under IP to illustrate a more complex involvement of the PFC in the contextual interference effect. IP and RP incur similar levels of bilateral PFC recruitment, but the processes underlying the recruitment are dissimilar. PFC recruitment during IP supports action reconstruction and memory elaboration while RP relies on PFC recruitment to maintain task variation information in working memory from trial to trial. While PFC recruitment under RP serves to enhance immediate performance, it does not support long-term performance.

Association between Stroop tasks and heart rate variability features in patients with somatic symptom disorder

ObjectivePatients with somatic symptom disorder (SSD) may have declined parasympathetic activity and selective attention to negative information. We combined Stroop tasks and heart rate variability (HRV) measurements to explore the brain mechanism of SSD. Methods104 SSD patients (64 women) and 100 healthy adults (76 women) received three Stroop tasks (the “cognitive” color-word Stroop, “emotional” emotion Stroop, and “cognitive and emotional” face-word Stroop) with low and high interference conditions. The key HRV indexes included high-frequency power (HF) and standard deviation of normal to normal RR intervals (SDNN). The generalized estimating equation model was used to examine the effects of SSD on three Stroop tasks performance (accuracy and reaction time) and HRV (HF and SDNN) controlling for sex, age, body mass index, and the levels of anxiety and depression. ResultsFor Stroop tasks, the significant group difference in emotion Stroop task with the high level of interference (SSD patients had lower accuracy than healthy ones) was only found in women. As for HRV, only men during color-word Stroop, women during emotion Stroop revealed significant between-group differences; SDNN in SSD men was higher than healthy men, and HF in SSD women was lower than healthy women controlling for the confounding factors. The significantly longer reaction time in SSD women than in healthy women diminished in the adjusted analysis. ConclusionEmotion Stroop task and HRV helps distinguish SSD patients from healthy adults, particularly in women. Sex-specific measures for early detection and intervention for SSD are suggested.

Spatial Reuse in IEEE 802.11ax WLANs

Dealing with massively crowded scenarios is one of the most ambitious goals of next-generation wireless networks. With this goal in mind, the IEEE 802.11ax amendment includes, among other techniques, the Spatial Reuse (SR) operation. The SR operation encompasses a set of unprecedented techniques that are expected to significantly boost Wireless Local Area Networks (WLANs) performance in dense environments. In particular, the main objective of the SR operation is to maximize the utilization of the medium by increasing the number of parallel transmissions. Nevertheless, due to the novelty of the operation, its performance gains remain largely unknown. In this paper, we first provide a gentle tutorial of the SR operation included in the IEEE 802.11ax. Then, we analytically model SR and delve into the new kinds of MAC-level interactions among network devices. Finally, we provide a simulation-driven analysis to showcase the potential of SR in various deployments, comprising different network densities and traffic loads. Our results show that the SR operation can significantly improve the medium utilization, especially in scenarios under high interference conditions. Moreover, our results demonstrate the non-intrusive design characteristic of SR, which allows enhancing the number of simultaneous transmissions with a low impact on the environment. We conclude the paper by giving some thoughts on the main challenges and limitations of the IEEE 802.11ax SR operation, including research gaps and future directions.

Study of Simulation Platform for BDS/INS/CNS Deep Integration Navigation

In this paper, INS/CNS (CINS) is integrated into a module, and then CINS and BDS are further combined to form a deep integrated BDS/INS/CNS navigation system, which can significantly improve the navigation, positioning, and attitude measurement accuracy under high dynamic and strong interference conditions. It has broad application prospects for specific users such as high-altitude long-endurance Unmanned Aerial Vehicle (UAV) and high-maneuvering glider. In order to verify and analyze the algorithm and performance of the deep integrated navigation system, the design and implementation of BDS/INS/CNS deep integrated navigation simulation platform are presented and the overall architecture, information flow, and the composition of each subsystem of the simulation platform are introduced. The simulation results show that, under high dynamic conditions, the position accuracy of the BDS/INS/CNS deep integrated navigation system is better than 1 m, the speed accuracy is better than 0.1 m/s, and the overall performance is better than the BDS/INS deep integrated navigation system. It also verifies the availability of the simulation platform, which has guiding significance for the next design of BDS/INS/CNS deep integrated navigation prototype.

Modeling and evaluation of enhanced reception techniques for ADS-B signals in high interference environments

The RTCA (Radio Technical Commission for Aeronautics) DO-260B document has stimulated in latest years the adoption of novel algorithms to improve the ability of receivers to detect and decode ADS-B (Automatic Dependent Surveillance-Broadcast) signals, with particular emphasis on preamble detection, declaration of bit state and confidence level, detection and correction of errors. Motivated by an industry-driven research project, this paper reports on performance analysis of a set of enhanced techniques that we have implemented for detection and decoding of ADS-B signals transmitted at 1090 MHz carrier frequency also in high interference conditions. An extensive set of results has been derived through a specifically developed simulation environment, able to closely model a wide range of operational scenarios by generating ADS-B frames and Mode A/C interfering signals. The simulation environment also includes an implementation of two RF (Radio Frequency) receiver chains that refer to a linear amplifier and a logarithmic amplifier, respectively. The investigations are mainly focused on evaluating the impact of the interference generated by Mode A/C replies on preamble detection and data decoding for ADS-B signals. In this regard, the ability of enhanced reception techniques to improve detection performance is assessed. Numerical results obtained from extensive simulation runs are reported and commented. They actually demonstrate that enhanced techniques are essential to guarantee adequate detection performance in the harsh environments envisaged by increased intensity of air traffic and the extensive use of ADS-B for traffic control.

Stochastic Estimation of Orientation Parameters of an Antenna Complex based on Strapdown Inertial System Measurements

The problem of high-precision determination of the spatial orientation of the antennas of radio complexes located on high-rise masts of various designs is considered. It is established that the methods currently used, based on measurements of satellite navigation systems and autonomous measurements of strapdown inertial orientation systems, do not provide the required accuracy in solving the problem. It is shown that the low accuracy of existing methods is due to both weak noise immunity of information processing algorithms and the lack of the ability to take into account the dynamic properties of orientation parameters measured under conditions of high intensity interference, the properties of which, as a rule, are not taken into account. A dynamic algorithm is proposed for estimating the stochastic orientation parameters of the antenna of a radio complex, which is invariant to the nature of the movement of the mast base and provides stability and the required estimation accuracy under general assumptions about the nature of the interference of the sensitive elements of the strapdown inertial orientation system. The Rodrigue–Hamilton parameter vector was used as the observed state vector – the antenna orientation parameter vector – and the vector of measurements of the angular velocity sensors of the strapdown inertial system was used as the observation vector for it. The instrumentation of the strapdown inertial system includes three accelerometers and three angular velocity sensors located orthogonally at the center of mass of the antenna. Based on the obtained non-linear stochastic equations for the dynamics of the change in the parameter vector of the current orientation of the strapdown inertial orientation system on a moving base and the equations of their observation, a stochastic model of measurement signals for sensitive elements of the strapdown inertial orientation system, a non-linear (generalized) Kalman filter is constructed that provides the desired solution to the problem of estimating the parameters of the current antenna orientation on a perturbed base. We present the results of a numerical experiment and a conclusion about the possibility of using a fi lter to solve the problem of operational orientation of antennas of radio engineering complexes using medium- and high-precision strapdown inertial orientation systems and without correction over a long time.

A role for the cerebellum in the control of verbal interference: Comparison of bilingual and monolingual adults

We evaluate brain structure sensitivity to verbal interference in a sentence interpretation task, building on previously reported evidence that those with better control of verbal interference show higher grey matter density in the posterior paravermis of the right cerebellum. We compare brain structure sensitivity to verbal interference control across two groups, English monolingual (N = 41) and multilingual (N = 46) adults. Using voxel-based morphometry, our primary goal was to identify and explore differences in regional patterns of grey matter sensitivity to performance on the sentence interpretation task, controlling for group variability in age, nonverbal reasoning and vocabulary knowledge. There was no group difference in performance but there was a significant group effect in grey matter sensitivity to task performance in our region of interest: stronger sensitivity in the paravermis in bilinguals compared to monolinguals in accuracy performance in the high (relative to low) verbal interference condition. This effect was observed when the linguistic interference was presented in an unfamiliar language (Greek) but not when presented in the familiar language (English). Our findings suggest that multilanguage acquisition mediates regional involvement within the language network, conferring enhanced functional plasticity within structures (including the paravermis) in the service of control of linguistic interference.

The medial prefrontal cortex is needed for resolving interference even when there are no changes in task rules and strategies.

The prefrontal cortex (PFC) plays a key role in behavioral flexibility, and the ability to resolve conflict from shifting strategies, task rules or attentional demands seems to be a hallmark of PFC function. Conflict also occurs in the domain of memory and the PFC plays an important role in the ability to cope with interference between competing retrieval targets. Previous studies often involved both interference and changes in task demands, which makes it difficult to determine the degree to which mnemonic interference per se engages PFC processing. We trained rats on a continuous matching to sample task in two conditions that varied in terms of the amount of interference present but not the task demands and found that temporary inactivation of the medial PFC caused a greater impairment in the high-interference condition. This result suggests that the PFC plays an important role in resolving interference which can be distinguished from its role in shifting task demands. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Deep Learning-Based Autoencoder for m-User Wireless Interference Channel Physical Layer Design

Deep learning (DL) based autoencoder (AE) has been proposed recently as a promising, and potentially disruptive approach to design the physical layer of beyond-5G communication systems. Compared to a traditional communication system with a multiple-block structure, the DL based AE approach provides a new paradigm to physical layer design with a pure data-driven and end-to-end learning based solution. In this article, we address the dynamic interference in a multi-user Gaussian interference channel. We show that standard constellation are not optimal for this context, in particular, for a high interference condition. We propose a novel adaptive DL based AE to overcome this problem. With our approach, dynamic interference can be learned and predicted, which updates the learning processing for the decoder. Compared to other machine learning approaches, our method does not rely on a fixed training function, but is adaptive and applicable to practical systems. In comparison with the conventional system using $n$ -psk or $n$ -QAM modulation schemes with zero force (ZF) and minimum mean square error (MMSE) equalizer, the proposed adaptive deep learning (ADL) based AE demonstrates a significant achievable BER in the presence of interference, especially in strong and very strong interference scenarios. The proposed approach has laid the foundation of enabling adaptable constellation for 5G and beyond communication systems, where dynamic and heterogeneous network conditions are envisaged.

Survival of the Fittest: Increased Stimulus Competition During Encoding Results in Fewer but More Robust Memory Traces.

Forgetting can be accounted for by time-indexed decay as well as competition-based interference processes. Although conventionally seen as competing theories of forgetting processes, Altmann and colleagues argued for a functional interaction between decay and interference. They revealed that, in short-term memory, time-based forgetting occurred at a faster rate under conditions of high proactive interference compared to conditions of low proactive interference. However, it is unknown whether interactive effects between decay-based forgetting and interference-based forgetting also exist in long-term memory. We employed a delayed memory recognition paradigm for visual indoor and outdoor scenes, measuring recognition accuracy at two time-points, immediately after learning and after 1 week, while interference was indexed by the number of images in a semantic category. We found that higher levels of interference during encoding led to a slower subsequent decay rate. In contrast to the findings in working-memory, our results suggest that a “survival of the fittest” principle applies to long-term memory processes, in which stimulus competition during encoding results in fewer, but also more robust memory traces, which decay at a slower rate. Conversely, low levels of interference during encoding allow more memory traces to form initially, which, however, subsequently decay at a faster rate. Our findings provide new insights into the mechanism of forgetting and could inform neurobiological models of forgetting.

Auditory-Induced Negative Emotions Increase Recognition Accuracy for Visual Scenes Under Conditions of High Visual Interference.

The effect of emotion on memory is powerful and complex. While there seems to be agreement that emotional arousal generally increases the likelihood that events are remembered, it is somewhat disputed whether also the valence of emotions influences memory. Specifically, several experiments by Kensinger and colleagues have provided evidence for the hypotheses that negative valanced emotions facilitate the encoding of perceptual details. On the other hand, Mather and colleagues have suggested that these results could be explained by confounding relationships of valence and arousal, i.e., that items that generate negative emotions are typically also more arousing. In this study, we provide a conceptual replication of Kensinger’s findings. We employed a novel experimental design, in which the effects of standardized emotional arousing sounds on recognition accuracy for neutral visual scenes was measured. We indirectly manipulated the amount of visual detail that was encoded, by requiring participants to memorize either single exemplars (low interference) or multiple exemplars (high interference) of visual scene categories. With increasing visual overlap in the high interference condition, participants were required to encode a high degree of visual detail to successfully remember the exemplars. The results obtained from 60 healthy human participants confirmed Kensinger’s hypothesis by showing that under conditions of high visual interference, negative valanced emotions led to higher levels of recognition accuracy compared to neutral and positive emotions. Furthermore, based on the normative arousal ratings of the stimulus set, our results suggest that the differential recognition effect cannot be explained by differing levels of arousal.

Worry is associated with inefficient functional activity and connectivity in prefrontal and cingulate cortices during emotional interference.

IntroductionAnxiety is known to impair attentional control particularly when Task demands are high. Neuroimaging studies generally support these behavioral findings, reporting that anxiety is associated with increased (inefficient) activity in dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) during attentional control Tasks. However, less is known about the relationship between worry (part of the cognitive dimension of trait anxiety) and DLPFC/ACC function and connectivity during attentional control. In the present study, we sought to clarify this relationship.MethodsForty‐one participants underwent functional magnetic resonance imaging (fMRI) during a composite Faces and Scenes Task with high and low emotional interference conditions. Individual worry levels were assessed using the Penn State Worry Questionnaire.ResultsDuring high but not low emotional interference, worry was associated with increased activity in ACC, DLPFC, insula, and inferior parietal cortex. During high emotional interference, worry was also associated with reduced functional connectivity between ACC and DLPFC. Trait anxiety was not associated with changes in DLPFC/ACC activity or connectivity during either Task condition.ConclusionsThe results are consistent with cognitive models that propose worry competes for limited processing resources resulting in inefficient DLPFC and ACC activity when Tasks demands are high. Limitations of the present study and directions for future work are discussed.

The effect of consistent and varied follow-through practice schedules on learning a table tennis backhand

ABSTRACTIn table tennis the follow-through action after a shot is an important part of skill execution. In this experiment, we aimed to extend literature around the contextual interference effect by investigating whether the way the follow-through is organised in practice affects learning of the backhand shot in table tennis. Thirty unskilled participants were allocated to blocked-variable practice, random-variable practice or a control-constant group and aimed backhand shots towards a target following ball projection from a machine. Each group completed these shots in a pre-test, a training phase with follow-through manipulations, a post-test, and a retention test. The random-variable group improved their shot accuracy from pre-test to post-test and from pre-test to retention test (both P < 0.01, d = 1.03), whereas neither the blocked-variable nor the control-constant group displayed any change in shot accuracy. Practising the follow-through in a random-variable fashion enhanced learning of the preceding shot compared with blocked-variable practice or no follow-through instructions. The benefits of learning motor skills under conditions of high contextual interference also apply to how follow-through actions are organised. The findings are valuable to coaches and suggest that instructions related to the follow-through action should be considered as well as the primary skill itself.