Observing the suppression of individual aversive memories from conscious awareness.

When reminded of an unpleasant experience, people often try to exclude the unwanted memory from awareness, a process known as retrieval suppression. Here we used multivariate decoding (MVPA) and representational similarity analyses on EEG data to track how suppression unfolds in time and to reveal its impact on item-specific cortical patterns. We presented reminders to aversive scenes and asked people to either suppress or to retrieve the scene. During suppression, mid-frontal theta power within the first 500 ms distinguished suppression from passive viewing of the reminder, indicating that suppression rapidly recruited control. During retrieval, we could discern EEG cortical patterns relating to individual memories-initially, based on theta-driven visual perception of the reminders (0 to 500 ms) and later, based on alpha-driven reinstatement of the aversive scene (500 to 3000 ms). Critically, suppressing retrieval weakened (during 360 to 600 ms) and eventually abolished item-specific cortical patterns, a robust effect that persisted until the reminder disappeared (780 to 3000 ms). Representational similarity analyses provided converging evidence that retrieval suppression weakened the representation of target scenes during the 500 to 3000 ms reinstatement window. Together, rapid top-down control during retrieval suppression abolished cortical patterns of individual memories, and precipitated later forgetting. These findings reveal a precise chronometry on the voluntary suppression of individual memories.

Enhancing Orbital Interaction in Spinel LiNi0.5Mn1.5O4 Cathode for High-Voltage and High-Rate Li-Ion Batteries.

High voltage cobalt-free spinel LiNi0.5Mn1.5O4 (LNMO) is well organized as a high-power cathode material for lithium (Li)-ion batteries, however, the weak interaction between the 3d orbital of the transition metal (TM) ions and the 2p orbital of oxygen (O) leads to the instability of crystal structural, hindering the long-term stable cycling of LNMO cathode especially at high temperatures. Here, a design strategy of orbital interaction is initiated to strengthen TM 3d-O 2p framework in P-doped LNMO (P-LNMO) by choosing phytic acid as P dopant, which can realize more uniform doping compared to regular phosphate. The results show that the enhancement of TM 3d-O 2p orbital interaction in P-LNMO can suppress the Jahn-Teller effect and subsequent dissolution of Mn, as well as lowers the energy barrier for Li ion insertion/extraction kinetics. As a result, superior electrochemical performances including high discharge capacity, stable cycling behavior and enhanced rate capability of P-LNMO are obtained. Significantly, the P-LNMO pouch cell shows great cycling stability with 97.4% capacity retention after 100 cycles.

State-dependent tACS effects reveal the potential causal role of prestimulus alpha traveling waves in visual contrast detection.

The intricate relationship between prestimulus alpha oscillations and visual contrast detection variability has been the focus of numerous studies. However, the causal impact of prestimulus alpha traveling waves on visual contrast detection remains largely unexplored. In our research, we sought to discern the causal link between prestimulus alpha traveling waves and visual contrast detection across different levels of mental fatigue. Using electroencephalography (EEG) alongside a visual detection task with 30 healthy adults (13 females; 17 males), we identified a robust negative correlation between prestimulus alpha forward traveling waves (FTW) and visual contrast threshold (VCT). Inspired by this correlation, we utilized 45°/-45° phase-shifted transcranial alternating current stimulation (tACS) in a sham-controlled, double-blind, within-subject experiment with 33 healthy adults (23 females; 10 males) to directly modulate these alpha traveling waves. After the application of 45° phase-shifted tACS, we observed a substantial decrease in FTW and an increase in backward traveling waves (BTW), along with a concurrent increase in VCT, compared with the sham condition. These changes were particularly pronounced under low fatigue state. The findings of state-dependent tACS effects reveal the potential causal role of prestimulus alpha traveling waves in visual contrast detection. Moreover, our study highlights the potential of 45°/-45° phase-shifted tACS in cognitive modulation and therapeutic applications.Significance Statement Visual contrast detection, despite consistent stimuli, frequently exhibits variability. This variability has been linked to prestimulus alpha neural oscillations in prior studies. Recently, there has been increased interest in exploring large-scale alpha traveling waves and their connection with visual processing. Yet, the role of these traveling waves in visual contrast detection remains unclarified. Through a combination of visual detection tasks, EEG data analysis, and 45°/-45° phase-shifted tACS, our study elucidates how prestimulus alpha traveling waves exert a potential causal influence on visual contrast detection.

Protective effect of ginsenoside Rb1 against aconitine cardiotoxicity studied by myocardial injury, action potential, and calcium signaling.

Aconitine is the main active component of Aconitum plants. Although aconitine has effects that include strengthening the heart, analgesia, anti-tumor, and immune-regulating effects, aconitine has both efficacy and toxicity, especially cardiotoxicity. Severe effects can include arrhythmia and cardiac arrest, which limits the clinical application of aconitine-containing traditional Chinese medicine. Ginsenoside Rb1(Rb1) is mainly found in plants, such as ginseng and Panax notoginseng, and has cardiovascular-protective and anti-arrhythmia effects. This study aimed to investigate the detoxifying effects of Rb1 on aconitine cardiotoxicity and the electrophysiological effect of Rb1 on aconitine-induced arrhythmia in rats. Pathological analysis, myocardial enzymatic indexes, and Western blotting were used to investigate the ameliorating effect of Rb1 on aconitine cardiotoxicity. Optical mapping was used to evaluate the effect of Rb1 on action potential and calcium signaling after aconitine-induced arrhythmia. Rb1 inhibited pathological damage caused by aconitine, decreased myocardial enzyme levels, and restored the balance of apoptotic protein expression by reducing the expression of Bax and cleaved caspase 3 and increasing the expression of Bcl-2, thereby reducing myocardial damage caused by aconitine. Rb1 also reduced the increase in heart rate caused by aconitine, accelerated action potential conduction and calcium signaling, and reduced the dispersion of action potential and calcium signal conduction. Rb1 reduced the cardiotoxicity of aconitine by attenuating aconitine-induced myocardial injury and inhibiting the aconitine-induced retardation of ventricular action potential and calcium signaling in rats.

Item-specific neural representations during human sleep support long-term memory.

Understanding how individual memories are reactivated during sleep is essential in theorizing memory consolidation. Here, we employed the targeted memory reactivation (TMR) paradigm to unobtrusively replaying auditory memory cues during human participants' slow-wave sleep (SWS). Using representational similarity analysis (RSA) on cue-elicited electroencephalogram (EEG), we found temporally segregated and functionally distinct item-specific neural representations: the early post-cue EEG activity (within 0 to 2,000 ms) contained comparable item-specific representations for memory cues and control cues, signifying effective processing of auditory cues. Critically, the later EEG activity (2,500 to 2,960 ms) showed greater item-specific representations for post-sleep remembered items than for forgotten and control cues, indicating memory reprocessing. Moreover, these later item-specific neural representations were supported by concurrently increased spindles, particularly for items that had not been tested prior to sleep. These findings elucidated how external memory cues triggered item-specific neural representations during SWS and how such representations were linked to successful long-term memory. These results will benefit future research aiming to perturb specific memory episodes during sleep.

Inhibition of AKR1Cs by liquiritigenin and the structural basis.

In vivo and in vitro studies have confirmed that liquiritigenin (LQ), the primary active component of licorice, acts as an antitumor agent. However, how LQ diminishes or inhibits tumor growth is not fully understood. Here, we report the enzymatic inhibition of LQ and six other flavanone analogues towards AKR1Cs (AKR1C1, AKR1C2 and AKR1C3), which are involved in prostate cancer, breast cancer, and resistance of anticancer drugs. Crystallographic studies revealed AKR1C3 inhibition of LQ is related to its complementarity with the active site and the hydrogen bonds net in the catalytic site formed through C7-OH, aided by its nonplanar and compact structure due to the saturation of the C2C3 double bond. Comparison of the LQ conformations in the structures of AKR1C1 and AKR1C3 revealed the induced-fit conformation changes, which explains the lack of isoform selectivity of LQ. Our findings will be helpful for better understanding the antitumor effects of LQ on hormonally dependent cancers and the rational design of selective AKR1Cs inhibitors.

Oxaliplatin-induced peripheral neurotoxicity in colorectal cancer patients: mechanisms, pharmacokinetics and strategies.

Oxaliplatin-based chemotherapy is a standard treatment approach for colorectal cancer (CRC). However, oxaliplatin-induced peripheral neurotoxicity (OIPN) is a severe dose-limiting clinical problem that might lead to treatment interruption. This neuropathy may be reversible after treatment discontinuation. Its complicated mechanisms are related to DNA damage, dysfunction of voltage-gated ion channels, neuroinflammation, transporters, oxidative stress, and mitochondrial dysfunction, etc. Several strategies have been proposed to diminish OIPN without compromising the efficacy of adjuvant therapy, namely, combination with chemoprotectants (such as glutathione, Ca/Mg, ibudilast, duloxetine, etc.), chronomodulated infusion, dose reduction, reintroduction of oxaliplatin and topical administration [hepatic arterial infusion chemotherapy (HAIC), pressurized intraperitoneal aerosol chemotherapy (PIPAC), and hyperthermic intraperitoneal chemotherapy (HIPEC)]. This article provides recent updates related to the potential mechanisms, therapeutic strategies in treatment of OIPN, and pharmacokinetics of several methods of oxaliplatin administration in clinical trials.

Frontal-occipital phase synchronization predicts occipital alpha power in perceptual decision-making.

Numerous studies of perceptual decision-making have shown that lower prestimulus alpha power leads to a higher hit rate in visual detection, which is believed to correlate with the top-down control. However, whether frontal-occipital phase synchronization underlying the top-down control could impact the occipital alpha power that directly affects the perceptual performance remains unclear. In this study, we used analyses of the general linear mixed model (GLMM) and event-related potentials (ERPs) to show that the prestimulus alpha power over the occipital area directly affected visual perception. Using both the univariate and multivariate methods, we found that low-frequency (4-30 Hz) frontal-occipital phase synchronization predicted the prestimulus alpha power over the occipital area. Overall, our results suggested that frontal-occipital phase synchronization could predict occipital alpha power that directly affects perceptual decision-making. Supplementary Information: The online version contains supplementary material available at 10.1007/s11571-022-09862-7.

Effects of Exogenous Auxin on Mesocotyl Elongation of Sorghum.

The length of sorghum mesocotyl plays a vital role in seed emergence from the soil, which is the foundation of healthy growth. In this study, we aimed to understand how exogenous auxin (IAA) promoted mesocotyl elongation of sorghum and its physiology mechanism. The results presented that exogenous IAA significantly promoted mesocotyl elongation in MS24B (short mesocotyl inbred line) by increasing the cell length, while with extra exogenous NPA (IAA inhibitor) application, the mesocotyl length presented a significant short phenotype. In Z210 (long mesocotyl inbred line), exogenous IAA had a slight effect on mesocotyl length elongation, while the NPA treatment decreased the mesocotyl length considerably. In MS24B, IAA treatment increased the activity of amylase to degrade starch to soluble sugar, and the activity of hexokinase was improved to consume the increased soluble sugar to offer more energy. The energy will help to increase the activity of PM H+-ATPase and the expression of expansin-related genes, which ultimately will promote the acidification of the plasma membrane in MS24B for cell elongation. Overall, the exogenous IAA functioned on the activation of energy metabolism, which in turn, inducted the acidification of the plasma membrane for mesocotyl elongation.

Updating memories of unwanted emotions during human sleep.

Post-learning sleep contributes to memory consolidation. Yet it remains contentious whether sleep affords opportunities to modify or update emotional memories, particularly when people would prefer to forget those memories. Here, we attempted to update memories during sleep, using spoken positive words paired with cues to recent memories of aversive events. Affective updating using positive words during human non-rapid eye movement (NREM) sleep, compared with using neutral words instead, reduced negative affective judgments in post-sleep tests, suggesting that the recalled events were perceived as less aversive. Electroencephalogram (EEG) analyses showed that positive words modulated theta and spindle/sigma activity; specifically, to the extent that theta power was larger for the positive words than for the memory cues that followed, participants judged the memory cues less negatively. Moreover, to the extent that sigma power was larger for the positive words than for the memory cues that followed, participants forgot more episodic details about aversive events. Notably, when the onset of individual positive words coincided with the up-phase of slow oscillations (a state characterized by increased cortical excitability during NREM sleep), affective updating was more successful. In sum, we altered the affective content of memories via the strategic pairing of positive words and memory cues during sleep, linked with EEG theta power increases and the slow oscillation up-phase. These findings suggest novel possibilities for modifying unwanted memories during sleep, which would not require people to consciously confront memories that they prefer to avoid.

Modulation of Sustained Attention by Theta-tACS over the Lateral and Medial Frontal Cortices.

Theta oscillations over the posterior medial frontal cortex (pMFC) and lateral prefrontal cortex (LPFC) play vital roles in sustained attention. Specifically, pMFC power and pMFC-LPFC synchronization correlate with cognitive control in sustained-attention-related tasks, but the causal relationships remain unknown. In the present study, we first analyzed the correlation between EEG theta oscillations (characterized by time-frequency power and phase-based connectivity) and the level of sustained attention (Experiment 1) and then utilized transcranial alternating current stimulation (tACS) to modulate theta oscillations and in turn observed its effects on sustained attention (Experiment 2). In Experiment 1, two time-frequency regions of interest (ROIs) were determined, in which high/low time-frequency power and high/low phase-based connectivity corresponded to high/low-level sustained attention. In Experiment 2, time-frequency power and phase-based connectivity of theta oscillations were compared between the sham and tACS groups within the time-frequency ROIs determined in Experiment 1. Results showed that phase-based connectivity between pMFC and LPFC significantly decreased in the tACS group compared with the sham group during the first five minutes of the poststimulation period. Moreover, a marginal trend existed that sustained attention was downregulated by tACS in the same time interval, suggesting that theta phase synchronization between pMFC and LPFC may play a causal role in sustained attention.

Optimistic amnesia: how online and offline processing shape belief updating and memory biases in immediate and long-term optimism biases.

When people are confronted with feedback that counters their prior beliefs, they preferentially rely on desirable rather than undesirable feedback in belief updating, i.e. an optimism bias. In two pre-registered EEG studies employing an adverse life event probability estimation task, we investigated the neurocognitive processes that support the formation and the change of optimism biases in immediate and 24 h delayed tests. We found that optimistic belief updating biases not only emerged immediately but also became significantly larger after 24 h, suggesting an active role of valence-dependent offline consolidation processes in the change of optimism biases. Participants also showed optimistic memory biases: they were less accurate in remembering undesirable than desirable feedback probabilities, with inferior memories of undesirable feedback associated with lower belief updating in the delayed test. Examining event-related brain potentials (ERPs) revealed that desirability of feedback biased initial encoding: desirable feedback elicited larger P300s than undesirable feedback, with larger P300 amplitudes predicting both higher belief updating and memory accuracies. These results suggest that desirability of feedback could bias both online and offline memory-related processes such as encoding and consolidation, with both processes contributing to the formation and change of optimism biases.

Attentional priorities drive effects of time pressure on altruistic choice.

Dual-process models of altruistic choice assume that automatic responses give way to deliberation over time, and are a popular way to conceptualize how people make generous choices and why those choices might change under time pressure. However, these models have led to conflicting interpretations of behaviour and underlying psychological dynamics. Here, we propose that flexible, goal-directed deployment of attention towards information priorities provides a more parsimonious account of altruistic choice dynamics. We demonstrate that time pressure tends to produce early gaze-biases towards a person's own outcomes, and that individual differences in this bias explain how individuals' generosity changes under time pressure. Our gaze-informed drift-diffusion model incorporating moment-to-moment eye-gaze further reveals that underlying social preferences both drive attention, and interact with it to shape generosity under time pressure. These findings help explain existing inconsistencies in the field by emphasizing the role of dynamic attention-allocation during altruistic choice.

The Spreading of Social Energy: How Exposure to Positive and Negative Social News Affects Behavior.

Social news, unlike video games or TV programs, conveys real-life interactions. Theoretically, social news in which people help or harm each other and violate rules should influence both prosocial and violation behaviors. In two experiments, we demonstrated the spreading effects of social news in a social interaction context emphasizing social conventions and a nonsocial interaction context emphasizing moral norms. Across the two studies, the results showed that positive social news increased cooperation (decreased defection) but had no effect on cheating, whereas negative social news increased cheating but with no change in cooperation (or defection). We conclude that there is a spreading impact of positive social news in the conventional norm domain and of negative social news in the moral norm domain.

Calm and smart? A selective review of meditation effects on decision making.

Over the past two decades, there has been a growing interest in the use of meditation to improve cognitive performance, emotional balance, and well-being. As a consequence, research into the psychological effects and neural mechanisms of meditation has been accumulating. Whether and how meditation affects decision making is not yet clear. Here, we review evidence from behavioral and neuroimaging studies and summarize the effects of meditation on social and non-social economic decision making. Research suggests that meditation modulates brain activities associated with cognitive control, emotion regulation and empathy, and leads to improved non-social and social decision making. Accordingly, we propose an integrative model in which cognitive control, emotional regulation, and empathic concern mediate the effects of meditation on decision making. This model provides insights into the mechanisms by which meditation affects the decision making process. More evidence is needed to test our explanatory model and to explore the function of specific brain areas and their interactive effects on decision making during meditation training.