The effect of chronic academic stress on intentional forgetting.

This study investigated whether chronic academic stress could affect the directed forgetting (DF) process. Both the stress group (undergoing preparation for a major academic examination) and the control group performed a DF task. A forgetting cue was presented after a to-be-forgotten (TBF) word, whereas no cue appeared after a to-be-remembered (TBR) item in the study phase. An old/new recognition test was used in the test phase. The results showed that (1) the stress group showed a higher level of self-reported stress, state anxiety, negative affect, and decreased cortisol awakening response (CAR) compared with the control group, suggesting a higher level of stress for the stress group. (2) Both groups showed superior recognition performance of TBR than TBF items, suggesting a DF effect. (3) The stress group showed inferior recognition performance of TBF items and an enhanced DF effect compared with the control group. These results demonstrated that the intentional memory control process might be enhanced under chronic academic stress.

Identification of two-phase flow patterns based on capacitance data of electrical capacitance tomography with semi-supervised generative adversarial network.

Currently, the flow pattern identification algorithms based on ECT (electrical capacitance tomography) technology have low identification accuracy for complex flow patterns and require a large amount of label data for learning. A novel flow pattern identification method based on a semi-supervised generative adversarial network (SGAN) with capacitance data of ECT is proposed. First, the principles of the ECT technique and general GAN are briefly described, and the model parameters, loss function, and training process of the SGAN are explained in detail. Second, a capacitance data sample set of 11 400 random flow patterns is constructed by co-simulations of COMSOL and MATLAB, and then, the SGAN and BP (back propagation) and SVM (support vector machine) network models are trained and validated by the training set. Finally, static experiments are conducted on the self-developed ECT system, and the identification results of different algorithms are compared and analyzed by modifying the label sample size of the training set. The experimental results show that SGAN maintains a higher average identification accuracy under the training condition where the number of label samples of SGAN is ten times smaller than that of the other two algorithms.

Left dorsolateral prefrontal cortex activation can accelerate stress recovery: A repetitive transcranial stimulation study.

In this study, a single high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) session was applied over the left dorsolateral prefrontal cortex (DLPFC) after a moderate-to-intense stressor to investigate whether left DLPFC stimulation could regulate cortisol concentration after stress induction. Participants were randomly divided into three groups (stress-TMS, stress, and placebo-stress). Stress was induced in both the stress-TMS and stress groups using the Trier Social Stress Test (TSST). The placebo-stress group received a placebo TSST. In the stress-TMS group, a single HF-rTMS session was applied over the left DLPFC after TSST. Cortisol was measured across the different groups, and each group's responses to the stress-related questionnaire were recorded. After TSST, both the stress-TMS and stress groups reported increased self-reported stress, state anxiety, negative affect, and cortisol concentration compared with the placebo-stress group, indicating that TSST successfully induced a stress response. Compared with the stress group, the stress-TMS group exhibited reduced cortisol levels at 0, 15, 30, and 45 min after HF-rTMS. These results suggest that left DLPFC stimulation after stress induction might accelerate the stress recovery.

A functional near-infrared spectroscopy investigation of item-method directed forgetting.

Whether directed forgetting is passive or active remains debated. Using functional near-infrared spectroscopy (fNIRS), blood-oxygen level-dependent responses of intentional forgetting were investigated in the item-method directed forgetting (DF) paradigm. During the study phase, each word was followed by a random remembering or forgetting cue indicating whether the word is to be remembered (TBR) or to be forgotten (TBF). A recognition test was used in the test phase and four cue-response conditions were obtained: remembering/forgetting cues associated with the subsequently remembered (TBR-r/TBF-r) or forgotten (TBR-f/TBF-f) words. Data from 16 healthy adult participants showed a DF effect. The fNIRS data revealed that, during the 5-9 s time window, the oxygenate hemoglobin (oxy-Hb) levels were higher during intentional forgetting compared to intentional remembering in the left inferior frontal (TBF-f vs. TBR-f) and right superior frontal gyrus (TBF-r vs. TBR-r), indicating more frontal inhibition involved during intentional forgetting. During the 9-11 s time window, the oxy-Hb level in the frontal and parietal gyrus was higher for forgetting than remembering cues, indicating that the TBF words might be automatically encoded. In sum, the TBF words might receive inhibition control triggered by forgetting cues and then be automatically encoded with the increase of the post-cue interval.

The ERP correlates of color-based center-surround inhibition in working memory.

The color-based center-surround inhibition (CSI) in working memory (WM) refers to that remembering a color inhibits the memory of similar colors but not of distinct colors. This study aimed to investigate the neural activity of color-based CSI in WM. Two WM items (distance 0°, 10°, 20°, 30°, 40°, 50°, or 60° in color space) were displayed sequentially, then one of them was retrieved to compare with a later probe. Behavioral results revealed that participants showed longer RTs for distances 20° and 30° than distances 0° and 40°, suggesting a CSI between similar items. ERP results revealed that: 1) WM item-induced late positive component (LPC) was more positive for distance 30° than the other distances, suggesting an enhanced resource allocation process for encoding similar items; 2) Cue-induced LPC was more positive for distances 20° and 30° than distances 0° and 60°, suggesting a greater difficulty for retrieving similar items; Cue-induced contingent negative variation was less negative for distance 20° than distances 40°, 50°, and 60°, suggesting a reduced response preparation process during retrieving similar items; 3) Probe-induced LPC was more positive for distances 20° and 30° than distances 50° and 60°, suggesting a greater effort for comparing probe with one item retrieved from two similar items. These results revealed a colored-based CSI during WM encoding and retrieval processes. An enhanced top-down control might be required to resolve the greater interference between similar items than identical or distinct items conditions.

The Automatic Emotion Regulation of Children Aged 8-12: An ERP Study.

Emotion regulation in childhood and adolescence is related to their social development. Better emotion regulation is associated with great individual academic performance and mental health. However, compared with the research on emotion regulation strategies, children's automatic emotion regulation has been less investigated. Using event-related potential (ERP) technology, this study adopts the cued-emotion Go/Nogo paradigm to investigate the processing characteristics of automatic emotion regulation in children aged 8-12 years. The current study selected 34 younger group [16 boys, 18 girls, mean (M) ± SD = 8.91 ± 0.75], and 31 older group [18 boys, 13 girls, M ± SD = 11.26 ± 0.45]. The results showed that, for Nogo trials, the amplitude of N2 and P3 evoked by emotional faces were significantly larger than those evoked by neutral faces, reflecting the cognitive conflict experienced and the process of children's automatic response inhibition to emotional stimuli, respectively. However, no significant difference in N2 and P3 amplitude were found in Go trials, which may indicate that children aged 8-12 showed similar top-down control and similar motivated attention in this experiment, respectively. Further analysis found that the negative affect of temperament was significantly positively correlated with Nogo-P3 induced by neutral pictures (r = 0.37, p < 0.001), and preadolescents' social anxiety was significantly positively correlated with Nogo-P3 followed by neutral pictures (r = 0.31, p < 0.01). These findings can provide inspiration and empirical support for the promotion and intervention of emotion regulation in children and adolescents.

The fronto-central N2 but not parietal P3 reflects response inhibition in the count/no-count task.

This study aimed to investigate whether the N2 or P3 component in the count/no-count task reflects response inhibition. The participants were asked to count/withhold counting the number of O/X letters in the count/no-count task, and to calculate the sum of all digits (i.e., 1/0) in the digital accumulation task. Therefore, four conditions were obtained in this study: count, no-count, Add 1, and Add 0. In the count and Add 1 conditions, the counting/calculation number need to be updated. In both no-count and Add 0 conditions, the memory of counting/calculation number need not to be updated; a No-go (withhold) instruction was given in the no-count condition, but a Go instruction was given in the Add 0 condition. Results showed that an enhanced fronto-central N2 was evoked in the no-count than in the Add 0 condition, indicating that a stronger response conflict or stronger inhibition might be triggered in the No-count condition. The frontocentral P3 showed no differences between no-count and Add 0 conditions, however, an enhanced centro-parietal P3 component was observed for the count relative to the no-count condition and for the Add 1 relative to the Add 0 condition, indicating that a greater amount of attentional resources might be consumed during memory updating process. Taken together, in the count/no-count task, the fronto-central N2 might reflect response inhibition or conflict and the parietal P3 might reflect attentional resource allocation but not response inhibition.

Chronic academic stress facilitates response inhibition: Behavioral and electrophysiological evidence.

Previous studies have found that acute stress can modulate response inhibition. However, the effect of chronic stress on response inhibition has not been investigated. A major examination was adopted as a chronic stressor in this study. Both the stress and control groups performed a modified Go/Nogo task. In each trial, a probe stimulus (left or right arrow) was presented immediately after the Go/Nogo task. The probe reaction time (RT) was used as an index of cognitive load during the task. Event-related potentials (ERPs) evoked by Go/Nogo stimuli were investigated. The RTs for the Go stimulus and the probe stimulus were shorter for the stress group than for the control group. This superior performance by stressed participants might suggest a promoted task processing efficiency during the dual task under stress. A smaller probe RT effect (RTNogo - RTGo) was found in the stress group than in the control group, indicating a facilitatory effect of stress on conflict resolution. The ERP results showed that the P2 Go/Nogo effect was smaller for the stress group than for the control group, driven by an increased P2 amplitude after Go trials for the stress group. This might indicate an enhancement of attentional resource allocation to the Go stimuli under stress. Both the Nogo P3 amplitude and the P3 Go/Nogo effect were enhanced in the stress group than in the control group, suggesting that conflict resolution was enhanced under stress. These results demonstrate that chronic academic stress might facilitate response inhibition by promoting conflict resolution.

Response inhibition and memory updating in the count/nocount task: an ERP study.

The present study aimed to separate the neural activities between response inhibition and memory updating processes in the Count/Nocount task. Memory load was manipulated to investigate the memory updating process. Within each trial, participants were asked to count/withhold counting the number of O/X letters in the Count/Nocount task. The participants were asked to silently add 1 if a Count letter was presented in the low load condition, and add 2 in the high load condition. Data from 28 healthy participants showed that: (1) in both high load and low load conditions, the latencies of P2 and N2 components were shorter for the Nocount than Count trials, indicating faster attentional orienting and conflict monitoring processes for the Nocount stimuli (i.e., inhibition processes triggered by the Nocount stimuli against those response execution processes triggered by Count stimuli); (2) more positive frontal P3 amplitudes were evoked for the Nocount relative to the Count stimuli, indicating a more intensive response inhibition process for the Nocount trials; (3) a more positive parietal P3 component was evoked for the low load relative to high load condition, indicating a more intensive working memory updating process for the high load condition. This load effect was absent for the frontal P3 component, suggesting that the frontal P3 might not be associated with the memory updating process. In sum, both the cognitive inhibition process (reflected by the frontal P3 component) and working memory updating process (reflected by the parietal P3 component) appear to be involved in the Count/Nocount task.

An ERP investigation of the working memory stroop effect.

This study aimed to explore the neural activity associated with the Working Memory (WM) Stroop effect. Stroop facilitation and interference effects in WM were also investigated by adding a neutral condition to the WM Stroop paradigm. In each trial, participants were first asked to remember a word in WM, then respond to the color of the subsequent rectangle. The word meaning and rectangular color were congruent, incongruent, or irrelevant (neutral). Finally, a probe word appeared and participants judged whether it was the same as the first presented word. For the color decision task, behavioral results showed that 1) RTs were longer for the incongruent than congruent condition, indicating a WM Stroop effect; 2) RTs were shorter for the congruent than neutral condition, indicating a WM Stroop facilitation effect; and 3) RTs were shorter for the incongruent than neutral condition, indicating no Stroop interference effect in WM. ERPs locked to the rectangle revealed that 1) greater N2 and P3 activity was evoked for the incongruent than congruent condition, indicating more intensive conflict detection and conflict resolution processes for the incongruent condition; and 2) enhanced N2 but decreased P3 components were evoked for the neutral than the congruent and incongruent conditions, indicating a more intensive conflict monitoring process but decreased conflict resolution process for the neutral condition. These results demonstrate that when WM content is congruent with the attention task, it can facilitate attention, but WM content may not interfere with attention when they are incongruent.

Attention and memory biases for aggressive information in college students with fragile high self-esteem.

In this study, we examined attention and memory biases for aggressive information in two groups of college students. Individuals with fragile high self-esteem (n = 30) and individuals with secure high self-esteem (n = 30) first performed a dot-probe task investigating attention bias, followed by a memory task. Incidental free recall of words presented in the memory task was then completed to assess memory bias. Results revealed that individuals with fragile high self-esteem exhibited significant attention and memory biases for aggressive words compared with secure high self-esteem individuals. Attention bias for aggressive words was positively correlated with memory bias in individuals with fragile high self-esteem, but no correlation was found for individuals with secure high self-esteem. These findings suggest that individuals with fragile high self-esteem selectively attend to and remember aggression-related information. They may process information in ways that are congruent with an aggression-related schema. This study reveals the aggressive cognitive processes of individuals with fragile high self-esteem, which may be related to aggression.

The extent of center-surround inhibition for colored items in working memory.

Remembering a color suppresses the representations of similar colors, but not of distinct colors, producing a center-surround inhibition (CSI) to resolve the competition between similar colors. In this study, three probe experiments were conducted to investigate the extent of CSI for colored items in working memory (WM). In Experiments 1 and 2, two WM items (distance 0°, 20°, 40°, or 60° in color space) were presented sequentially, one of which was cued to compare with the probe (matched or non-matched). The probe distance between the non-matched probe (NP) and cued WM item was 30° in Experiment 1 and 30°, 60°, or 90° in Experiment 2. Results for matched probe (MP) revealed that two WM items might produce a maximal CSI at distance 20°, and fall outside each other's inhibitory surround at distance 40°. However, the CSI was not found in the NP conditions (i.e., distance 30°, 60°, or 90°) in both Experiments 1 and 2, suggesting that the NP might be unsuitable for investigating the CSI in WM. In Experiment 3, participants were asked to discriminate which WM item was matched with the probe (no NP conditions). RTs were slowest at distance 20°, but were almost equal across distance 30°, 40°, 50°, or 60°. These results demonstrated that two WM items might produce a maximal CSI at distance 20°, and begin to fall outside each other's inhibitory surround at distance 30°.

Influence of global precedence on spatial Stroop effect.

In this study, two experiments were conducted to investigate the influence of global precedence on spatial Stroop effect. Combined stimuli were adopted. In Experiment 1, a Chinese character "" (up) or "" (down) was embedded in an up- or down-pointing arrow; the character was the local feature, whereas the arrow was the global feature. In the spatial task, participants were asked to identify arrow orientation, whereas in the meaning task, they were asked to respond to the character meaning. The results revealed that the RTs were longer for the incongruent trials than for the congruent trials (i.e., spatial Stroop effect) in meaning task, but not in the spatial task. In Experiment 2, an arrow was embedded in a character; the arrow was the local feature, whereas the character was the global feature. The results showed that the effect was found in the spatial task, but not in the meaning task. These results suggest that when combined stimuli are adopted, the spatial Stroop effect is modulated by global precedence. Specifically, the magnitudes of spatial Stroop effect were smaller in the global feature identification than those in the local feature identification.

Acute psychological stress promotes general alertness and attentional control processes: An ERP study.

The current study investigated the influence of acute psychological stress on selective attention processes. After an acute stressor or a control condition, 20 participants performed an arrow-based version of the Eriksen flanker task, while ERPs (N1, N2, P3), reaction times, accuracy, subjective stress, and electrocardiogram signal were measured. Results showed elevated self-report stress, negative affect, state anxiety, heart rate, and reduced high-frequency heart rate variability in the stress block than in the control block, indicating that the flanker task was performed in a stressful situation. In the flanker task, faster response and larger flanker effect of accuracy were observed for the stress block relative to the control block, indicating increased arousal level and improved conflict detection under stress. Event-related potentials locked to target stimuli in the flanker task revealed that (a) frontal N1 was amplified in the stress block than in the control block, indicating elevated vigilance level under stress; (b) frontal N2 was increased in the stress block than in the control block for both congruent and incongruent trials, indicating more intensive attention control under stress; and (c) Increased P3 in the stress block than in the control block may reflect more allocation of neural resources as a consequence of improved attentional control under stress. These findings suggest that acute psychological stress increases general alertness and promotes attentional control in selective attention processes.

Long non-coding RNA Mirt2 prevents TNF-α-triggered inflammation via the repression of microRNA-101.

Parkinson's disease is normally accompanied by excessive inflammation. Myocardial infraction associated transcript 2 (Mirt2) has an activity to relieve inflammation in numerous cell types. Here, we aimed to investigate whether Mirt2 could elevate the resistance of SH-Sy5y cells to inflammation. Tumor necrosis factor alpha (TNF-α) was used to induce inflammation in SH-Sy5y cells. Mirt2 overexpressed or silenced cells were established. MicroRNA-101 (miR-101) mimic was used to up-regulate miR-101. Viable and apoptotic cells as well as reactive oxidative species (ROS) were detected after staining. Proteins associated with apoptosis, interleukin (IL) and signaling regulators were evaluated by Western blot. IL secretion was assessed by ELISA. Mirt2 and miR-101 were determined by qRT-PCR. We discovered that TNF-α weakened viability of SH-Sy5y cells and resulted in sensitivity to apoptosis with cleavage of PARP and caspase-3. Expression and secretion of IL-6 as well as generation of ROS were facilitated by TNF-α. However, Mirt2 overexpression moderated TNF-α-caused apoptosis associated with inflammation and oxidative stress. Mirt2 suppressed TNF-α-induced accumulation of miR-101, and based on this Mirt2 exhibited anti-inflammatory roles. Additionally, TNF-α-triggered phosphorylation of regulators was blocked by Mirt2 while restored by miR-101 mimic. In short Mirt2 overexpression exhibited anti-inflammatory properties through miR-101 suppression. Through down-regulating miR-101, Mirt2 blocked TNF-α-triggered NF-κB/p38MAPK pathway.

The role of forgetting cues in directed forgetting: Ceasing maintenance rehearsal.

The effect of forgetting cues on maintenance rehearsal in item-method directed forgetting (DF) paradigm was explored from behavioral and electrophysiological evidence. In Experiment 1, maintenance rehearsal was induced by a maintenance cue. Specifically, after the studied word, a maintenance (M) cue was presented before the presentation of a remembering/forgetting cue. When an M cue appeared, participants were required to wait for the following remembering (M-R) or forgetting (M-F) cue to determine whether the word needs to be remembered or not, and words were kept in short-term memory with maintenance rehearsal until the presentation of M-R/M-F cues. Four conditions were utilized: maintain-remembering (M-R), maintain-forgetting (M-F), maintenance (M), and forgetting (F). The results showed that, 1) superior recognition was found for the M-R relative to the M-F words, revealing a typical DF effect; 2) No recognition difference was found between M and M-F words, indicating that M-F cues showed little effect in promoting forgetting; 3) Inferior recognition was found for F than M words, indicating that the maintenance rehearsal might cease or be reduced by the presentation of F cues. In Experiment 2, event related potentials time-locked to cue (M-R, M-F, M, and F cues) onset during study phase. An enhanced fronto-central P3a component was evoked for F relative to M cues, indicating a more intensive attention orienting or attentional inhibition process triggered by F cues. These results demonstrated that forgetting cues might trigger an inhibition process to terminate the maintenance rehearsal process.

Elaborately rehearsed information can be forgotten: A new paradigm to investigate directed forgetting.

In previous item-method directed forgetting (DF) studies, forgetting may have occurred when the maintenance rehearsal of memory items was performed. In this study, a modified item-method DF paradigm was adopted to investigate whether forgetting instruction could produce a positive effect on forgetting the items that were elaborately rehearsed. During the study phase, a to-be-forgotten (TBF) word was followed by a forgetting cue. If no cue followed, the word was a to-be-remembered (TBR) item. Participants were required to intentionally memorize the word when it appeared. During the test phase, a yes/no recognition (Experiment 1) or a remember/know procedure (Experiment 2) was adopted. The behavioural results revealed that both the hit rate (Experiment 1) and remembering rate (Experiment 2) were higher for TBR relative to TBF words. For correctly identified old words, reaction times were consistently shorter for TBR compared to TBF words. These results revealed superior memory retention for TBR than for TBF words. The event-related potential (ERP) results revealed that, during both FN400 and late-positive complex (LPC) time windows, the remembered TBR words evoked more positive ERPs than the remembered TBF words and correctly rejected (CR) words (i.e., FN400 and LPC old/new effects). However, more negative ERPs were evoked for both remembered and forgotten TBF words than for CR words during the LPC time window (i.e., reversed LPC old/new effect). These results demonstrated that TBF words were associated with lower level of familiarity and recollection process than TBR words. The memory representation of TBF information might be inhibited.

Forgetting cues are ineffective in promoting forgetting in the item-method directed forgetting paradigm.

This study aims to investigate the effectiveness of forgetting cues in an item-method directed forgetting (DF) paradigm. A modified no-cue (NC) condition, in which participants could not adopt intentional forgetting strategy, was added to an item-method DF paradigm. Memory retention was compared between NC condition and to-be-forgotten (TBF) condition. The results revealed that the recognition reaction times (RTs) were shorter for the remembered TBF (TBF-R) words than for the remembered NC (NC-R) words, and were longer for the forgotten TBF words relative to the forgotten NC words, indicating that participants might be more familiar with the TBF words than the NC words. Event-related potential results showed that both LPC activity and frontal old/new effect were enhanced for TBF-R words relative to the NC-R words. These results might indicate that participants were more familiar with TBF words than NC words. This study further supports the view that forgetting cues may not in fact promote forgetting in the item-method DF paradigm.

The spatial filtering method of particle velocity measurement based on linear electrostatic sensor matrix.

An electrostatic sensor is a powerful tool for measuring flow parameters of gas-solid flow. In this study, a linear electrostatic sensor matrix (LESM) is designed to measure local particle average velocity within pipeline. The 3D simulation model of the LESM is built, and its spatial filtering effect is analyzed by the finite element method. The quantitative relational expression between peak frequency of the LESM and particle velocity is obtained. Then, the LESM-based particle velocimeter is further developed and its performance is verified on a gravity transport test rig. Simulation and experimental results demonstrate that the measurement method is capable of eliminating the effect of particle size and particle spatial position on velocity measurement and measuring velocity with a relative error not greater than 7.5%, while the standard deviation of the consecutive velocity measurement is within ±9.96% over the velocity range of 2.34-4.75 m/s.