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How IRF7 promotes autoimmune B cell responses and systemic autoimmunity is unclear. Analysis of spontaneous SLE-prone mice deficient in IRF7 uncovered the IRF7 role in regulating autoimmune germinal center (GC), plasma cell (PC) and autoantibody responses and disease. IRF7, however, was dispensable for foreign antigen driven GC, PC and antibody responses. Competitive bone marrow (BM) chimeras highlighted the importance of IRF7 in hematopoietic cells in spontaneous GC and PC differentiation. Single-cell-RNAseq of SLE-prone B cells indicated IRF7 mediated B cell differentiation through GC and PC fates. Mechanistic studies revealed that IRF7 promoted B cell differentiation through GC and PC fates by regulating the transcriptome, translation, and metabolism of SLE-prone B cells. Mixed BM chimeras demonstrated a requirement for B cell-intrinsic IRF7 in IgG autoantibody production but not sufficient for promoting spontaneous GC and PC responses. Altogether, we delineate previously unknown B cell-intrinsic and -extrinsic mechanisms of IRF7-promoted spontaneous GC and PC responses, loss of tolerance, autoantibody production and SLE development., Competing Interests: Competing interests: The authors have no financial conflicts of interests to disclose.

Visual working memory is thought to have a fixed capacity limit. However, recent evidence suggests that a greater number of real-world objects than simple features (i.e., colors) can be maintained, an effect termed the object benefit. Here, we examined whether this object benefit in visual working memory is due to qualitatively different memory processes employed for meaningful stimuli compared to simple features. In online samples of young adults, real-world objects were better remembered than colors, had higher measures of recollection, and showed a greater proportion of high-confidence responses (Exp. 1). Objects were also remembered better than their scrambled counterparts (Exp. 2), suggesting that this benefit is related to semantic information, rather than visual complexity. Critically, the specific objects that were likely to be remembered with high confidence were highly correlated across experiments, consistent with the idea that some objects are more memorable than others. Visual working memory performance for the least-memorable objects was worse than that of colors and scrambled objects. These findings suggest that real-world objects give rise to recollective, or at least high-confidence, responses at retrieval that may depend on activation of semantic features, but that this effect is limited to certain objects., (© 2024. The Psychonomic Society, Inc.)

Previous research has demonstrated greater visual working memory (VWM) performance for real-world objects compared with simple features. Greater amplitudes of the contralateral delay activity (CDA)-a sustained event-related potential measured during the delay period of a VWM task-have also been noted for meaningful stimuli, despite being thought of as a neural marker of a fixed working memory capacity. The current study aimed to elucidate the factors underlying improved memory performance for real-world objects by isolating the relative contributions of perceptual complexity (i.e., number of visual features) and conceptual meaning (i.e., availability of semantic, meaningful features). Participants (N = 22) performed a lateralized VWM task to test their memory of intact real-world objects, scrambled real-world objects and colours. The CDA was measured during both encoding and WM retention intervals (600-1000 ms and 1300-1700 ms poststimulus onset, respectively), and behavioural performance was estimated by using d' (memory strength in a two-alternative forced choice task). Behavioural results revealed significantly better performance within-subjects for real-world objects relative to scrambled objects and colours, with no difference between colours and scrambled objects. The amplitude of the CDA was also largest for intact real-world objects, with no difference in magnitude for scrambled objects and colours, during working memory maintenance. However, during memory encoding, both the colours and intact real-world objects had significantly greater amplitudes than scrambled objects and were comparable in magnitude. Overall, findings suggest that conceptual meaning (semantics) supports the memory benefit for real-world objects., (© 2024. The Psychonomic Society, Inc.)

Studies suggest that visual short-term memory (VSTM) is a continuous resource that can be flexibly allocated using probabilistic cues that indicate test likelihood (i.e., goal-directed attentional priority to those items). Previous studies using simultaneous cues have not examined this flexible allocation beyond two distinct levels of priority. Moreover, previous studies have not examined whether there are individual differences in the ability to flexibly allocate VSTM resources, as well as whether this ability benefits from practice. The current study used a continuous report procedure to examine whether participants can use up to three levels of attentional priority to allocate VSTM resources via simultaneous probabilistic spatial cues. Three experiments were performed with differing priority levels, cues, and cue presentation times. Group level analysis demonstrated flexible allocation of VSTM resources; however, there was limited evidence that participants could use three goal-directed priority levels. A temporal analysis suggested that task fatigue, rather than practice effects, may interact with item priority. A Bayesian individual-differences analysis revealed that a minority of participants were using three levels of attentional priority, demonstrating that, while possible, it is not the predominant pattern of behaviour. Thus, we provided evidence that flexible allocation to three attention levels is possible under simultaneous cuing conditions for a minority of participants. Flexible allocation to three categories may be interpreted as a skill of high-performing participants akin to high memory capacity., (© 2023. The Psychonomic Society, Inc.)

T-cell receptor stimulation triggers cytosolic Ca 2+ signaling by inositol-1,4,5-trisphosphate (IP 3 )-mediated Ca 2+ release from the endoplasmic reticulum (ER) and Ca 2+ entry through Ca 2+ release-activated Ca 2+ (CRAC) channels gated by ER-located stromal-interacting molecules (STIM1/2). Physiologically, cytosolic Ca 2+ signaling manifests as regenerative Ca 2+ oscillations, which are critical for nuclear factor of activated T-cells-mediated transcription. In most cells, Ca 2+ oscillations are thought to originate from IP 3 receptor-mediated Ca 2+ release, with CRAC channels indirectly sustaining them through ER refilling. Here, experimental and computational evidence support a multiple-oscillator mechanism in Jurkat T-cells whereby both IP 3 receptor and CRAC channel activities oscillate and directly fuel antigen-evoked Ca 2+ oscillations, with the CRAC channel being the major contributor. KO of either STIM1 or STIM2 significantly reduces CRAC channel activity. As such, STIM1 and STIM2 synergize for optimal Ca 2+ oscillations and activation of nuclear factor of activated T-cells 1 and are essential for ER refilling. The loss of both STIM proteins abrogates CRAC channel activity, drastically reduces ER Ca 2+ content, severely hampers cell proliferation and enhances cell death. These results clarify the mechanism and the contribution of STIM proteins to Ca 2+ oscillations in T-cells., Competing Interests: Conflict of interest Mohamed Trebak is a consultant for Seeker Biologics Inc, and is a member of the editorial board of the J. Biol. Chem. The remaining authors declare no competing interests., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Working memory (WM) performance can be improved by an informative cue presented during storage. This effect, termed a retrocue benefit, can be used to study limits on how human observers prioritize information stored in WM for behavioral output. There is disagreement about whether retrocue benefits extend to multiple WM locations. Here, we hypothesized that multiple retrocues may improve some aspects of memory performance (e.g., a reduction in random guessing) while worsening others (e.g., an increase in the probability of reporting a feature presented at a non-probed location). We tested this possibility in three experiments. Participants remembered arrays of four orientations or colors over a brief delay, and spatial retrocues instructed participants to prioritize zero, one, two, or all four remembered orientations for possible report. At the end of the trial, participants recalled the orientation that appeared at one location. The results of this study revealed that participants' recall errors were lower during cue-one relative to cue-two and cue-four trials, and this benefit was driven primarily by a reduction in random guessing during cue-one trials. We found no evidence suggesting that multiple spatial cues (i.e., during cue-two trials) induced a trade-off between memory precision, random guessing, and non-target reports compared to neutral trials (i.e., cue-zero or cue-four). Thus, cuing participants to prioritize information appearing at multiple unique spatial positions led to no improvement in memory performance compared to neutral or no-cue trials, providing additional support for the view that retrocue benefits on WM performance are limited to a single spatial location at a time., (© 2023. The Psychonomic Society, Inc.)

Previous research has demonstrated that as people age, visual working memory (VWM) declines. One potential explanation for this decline is that older adults are less able to ignore irrelevant information, which contributes to VWM filtering deficits. Most research examining age differences in filtering ability has used positive cues (indicating which items to pay attention to), but negative cues (indicating which items to ignore) may be even harder for older adults to implement as some work suggests that negatively cued items are first paid attention to before they are suppressed. The current study aimed to test whether older adults can use negative cues to filter irrelevant information from VWM. Across two experiments, young and older adults were presented with two (Experiment 1) or four (Experiment 2) display items, preceded by a neutral, negative, or positive cue. After a delay, participants reported the target's orientation in a continuous-response task. Results show that both groups benefitted from being provided with a cue (positive or negative) compared to no cue (i.e., neutral condition), but the benefit was smaller for negative cues. Thus, although negative cues aid in filtering of VWM, they are less effective than positive cues, possibly due to residual attention being directed towards distractor items., (© 2023. The Psychonomic Society, Inc.)

The essential role of store-operated Ca 2+ entry (SOCE) through Ca 2+ release-activated Ca 2+ (CRAC) channels in T cells is well established. In contrast, the contribution of individual Orai isoforms to SOCE and their downstream signaling functions in B cells are poorly understood. Here, we demonstrate changes in the expression of Orai isoforms in response to B cell activation. We show that both Orai3 and Orai1 mediate native CRAC channels in B cells. The combined loss of Orai1 and Orai3, but not Orai3 alone, impairs SOCE, proliferation and survival, nuclear factor of activated T cells (NFAT) activation, mitochondrial respiration, glycolysis, and the metabolic reprogramming of primary B cells in response to antigenic stimulation. Nevertheless, the combined deletion of Orai1 and Orai3 in B cells did not compromise humoral immunity to influenza A virus infection in mice, suggesting that other in vivo co-stimulatory signals can overcome the requirement of BCR-mediated CRAC channel function in B cells. Our results shed important new light on the physiological roles of Orai1 and Orai3 proteins in SOCE and the effector functions of B lymphocytes., Competing Interests: SE, RY, XZ, AF, YW, KB, AT, PX, VW, MJ, TP, ZR No competing interests declared, AS owns stock options and is a consultant for Creegh Pharmaceuticals, SF is scientific co-founder of Calcimedica, MT Reviewing editor, eLife, (© 2023, Emrich et al.)

Sustained contralateral delay activity emerges in the retention period of working memory (WM) tasks and has been commonly interpreted as an electrophysiological index of the number of items held in a discrete-capacity WM resource. More recent findings indicate that these visual and tactile components are sensitive to various cognitive operations beyond the storage of discrete items in WM. In this Perspective, we present recent evidence from unisensory and multisensory visual and tactile WM tasks suggesting that, in addition to memory load, sensory delay activity may also be indicative of attentional and executive processes, as well as reflecting the flexible, rather than discrete, allocation of a continuous WM resource. Together, these findings challenge the traditional model of the functional significance of the contralateral delay activity as a pure measure of item load, and suggest that it may also reflect executive, attentional, and perceptual mechanisms operating in hierarchically organized WM systems., (© 2022 Massachusetts Institute of Technology.)

Antigen receptor stimulation triggers cytosolic Ca 2+ signals, which activate transcriptional and metabolic programs critical for immune function. B-cell receptor (BCR) engagement causes rapid cytosolic Ca 2+ rise through the ubiquitous store-operated calcium entry (SOCE) pathway. Slc8b1, which encodes the mitochondrial Na + /Ca 2+ exchanger (NCLX), extrudes Ca 2+ out of the mitochondria and maintains optimal SOCE activity. Inhibition of NCLX in DT40 and A20 B lymphocyte lines was recently shown to impair cytosolic Ca 2+ transients in response to antigen-receptor stimulation, however the downstream functional consequences of this impairment remain unclear. Here, we generated Slc8b1 knockout A20 B-cell lines using CRISPR/Cas9 technology and B-cell specific Slc8b1 knockout mice. Surprisingly, while loss of Slc8b1 in B lymphocytes led to reduction in SOCE, it had a marginal effect on mitochondrial Ca 2+ extrusion, suggesting that NCLX is not the major mitochondrial Ca 2+ extrusion mechanism in B cells. Furthermore, endoplasmic reticulum (ER) Ca 2+ content and rates of ER depletion and refilling remained unaltered in Slc8b1 knockout B cells. Slc8b1 deficiency increased mitochondrial production of oxidants, reduced mitochondrial bioenergetics and altered mitochondrial ultrastructure. B-cell specific Slc8b1 knockout mice showed reduced germinal center B cell responses following foreign antigen and pathogen driven immune responses. Our studies provide novel insights into the function of Slc8b1 in germinal center B cells and its contribution to B-cell signaling and effector function., Competing Interests: Declaration of Competing Interest Mohamed Trebak is a paid consultant of Seeker Biologicals Inc. The other authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2022. Published by Elsevier Ltd.)

The structural changes of airway smooth muscle (ASM) that characterize airway remodeling (AR) are crucial to the pathogenesis of asthma. During AR, ASM cells dedifferentiate from a quiescent to a proliferative, migratory, and secretory phenotype. Calcium (Ca 2+ ) is a ubiquitous second messenger that regulates many cellular processes, including proliferation, migration, contraction, and metabolism. Furthermore, mitochondria have emerged as major Ca 2+ signaling organelles that buffer Ca 2+ through uptake by the mitochondrial Ca 2+ uniporter and extrude it through the Na + /Ca 2+ exchanger (NCLX/Slc8b1). Here, we show using mitochondrial Ca 2+ -sensitive dyes that NCLX only partially contributes to mitochondrial Ca 2+ extrusion in ASM cells. Yet, NCLX is necessary for ASM cell proliferation and migration. Through cellular imaging, RNA-Seq, and biochemical assays, we demonstrate that NCLX regulates these processes by preventing mitochondrial Ca 2+ overload and supporting store-operated Ca 2+ entry, activation of Ca 2+ /calmodulin-dependent kinase II, and transcriptional and metabolic reprogramming. Using small animal respiratory mechanic measurements and immunohistochemistry, we show that smooth muscle-specific NCLX KO mice are protected against AR, fibrosis, and hyperresponsiveness in an experimental model of asthma. Our findings support NCLX as a potential therapeutic target in the treatment of asthma., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Store-operated Ca 2+ entry (SOCE) is a ubiquitous Ca 2+ signaling pathway that is evolutionarily conserved across eukaryotes. SOCE is triggered physiologically when the endoplasmic reticulum (ER) Ca 2+ stores are emptied through activation of inositol 1,4,5-trisphosphate receptors. SOCE is mediated by the Ca 2+ release-activated Ca 2+ (CRAC) channels, which are highly Ca 2+ selective. Upon store depletion, the ER Ca 2+ -sensing STIM proteins aggregate and gain extended conformations spanning the ER-plasma membrane junctional space to bind and activate Orai, the pore-forming proteins of hexameric CRAC channels. In recent years, studies on STIM and Orai tissue-specific knockout mice and gain- and loss-of-function mutations in humans have shed light on the physiological functions of SOCE in various tissues. Here, we describe recent findings on the composition of native CRAC channels and their physiological functions in immune, muscle, secretory, and neuronal systems to draw lessons from transgenic mice and human diseases caused by altered CRAC channel activity.

Airway remodeling and airway hyperresponsiveness are central drivers of asthma severity. Airway remodeling is a structural change involving the dedifferentiation of airway smooth muscle (ASM) cells from a quiescent to a proliferative and secretory phenotype. Here, we show up-regulation of the endoplasmic reticulum Ca 2+ sensor stromal-interacting molecule 1 (STIM1) in ASM of asthmatic mice. STIM1 is required for metabolic and transcriptional reprogramming that supports airway remodeling, including ASM proliferation, migration, secretion of cytokines and extracellular matrix, enhanced mitochondrial mass, and increased oxidative phosphorylation and glycolytic flux. Mechanistically, STIM1-mediated Ca 2+ influx is critical for the activation of nuclear factor of activated T cells 4 and subsequent interleukin-6 secretion and transcription of pro-remodeling transcription factors, growth factors, surface receptors, and asthma-associated proteins. STIM1 drives airway hyperresponsiveness in asthmatic mice through enhanced frequency and amplitude of ASM cytosolic Ca 2+ oscillations. Our data advocates for ASM STIM1 as a target for asthma therapy., Competing Interests: The authors declare no competing interest., (Copyright © 2021 the Author(s). Published by PNAS.)

Background: Inflammation of diverticula, which are outpouchings of the colonic bowl wall, causes diverticulitis. Severe cases of diverticulitis require surgical intervention. Through RNA-seq analysis of intestinal tissues, we previously found that the innate immune response was deregulated in surgical diverticulitis patients. In that study, pro-inflammatory and macrophage markers were differentially expressed in the colons of diverticulitis versus control patients. Here we investigate CD163L1 + macrophages and the pro-inflammatory chemokine, CXCL10, in diverticulitis., Materials and Methods: We assessed tissue from an uninvolved area adjacent to a region of the sigmoid colon chronically affected by diverticulitis and performed Spearman's correlation on transcripts associated with macrophage signaling. We identified altered CD163L1 and CXCL10 gene expression levels that we confirmed by RT-qPCR analysis on an independent cohort of diverticulitis patients and controls. We used immunofluorescence microscopy to localize CD163L1 + macrophages and CXCL10 levels in intestinal tissue and ELISA to measure CXCL10 levels in patient serum., Results: We found a positive correlation between intestinal CD163L1 and CXCL10 gene expression and an increased number of CD163L1 + macrophages in the sigmoid colons of diverticulitis patients relative to controls (P = 0.036). Macrophages at the apices of colonic crypts expressed the chemokine CXCL10. Correspondingly, these diverticulitis patients also displayed heightened CXCL10 levels in their serum (P = 0.007)., Conclusions: We identified a novel population of CD163L1 + CXCL10 + macrophages in the colonic crypts of diverticulitis patients and demonstrated increased expression of serum CXCL10 in these patients. CXCL10 may serve as a prognostic biomarker to aid in clinical decision making for diverticulitis patients., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Mitochondrial Ca 2+ uptake tailors the strength of stimulation of plasma membrane phospholipase C-coupled receptors to that of cellular bioenergetics. However, how Ca 2+ uptake by the mitochondrial Ca 2+ uniporter (MCU) shapes receptor-evoked interorganellar Ca 2+ signaling is unknown. Here, we used CRISPR/Cas9 gene knockout, subcellular Ca 2+ imaging, and mathematical modeling to show that MCU is a universal regulator of intracellular Ca 2+ signaling across mammalian cell types. MCU activity sustains cytosolic Ca 2+ signaling by preventing Ca 2+ -dependent inactivation of store-operated Ca 2+ release-activated Ca 2+ channels and by inhibiting Ca 2+ extrusion. Paradoxically, MCU knockout (MCU-KO) enhanced cytosolic Ca 2+ responses to store depletion. Physiological agonist stimulation in MCU-KO cells led to enhanced frequency of cytosolic Ca 2+ oscillations, endoplasmic reticulum Ca 2+ refilling, nuclear translocation of nuclear factor for activated T cells transcription factors, and cell proliferation, without altering inositol-1,4,5-trisphosphate receptor activity. Our data show that MCU has dual counterbalancing functions at the cytosol-mitochondria interface, whereby the cell-specific MCU-dependent cytosolic Ca 2+ clearance and buffering capacity of mitochondria reciprocally regulate interorganellar Ca 2+ transfer and nuclear factor for activated T cells nuclear translocation during receptor-evoked signaling. These findings highlight the critical dual function of the MCU not only in the acute Ca 2+ buffering by mitochondria but also in shaping endoplasmic reticulum and cytosolic Ca 2+ signals that regulate cellular transcription and function., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

When searching for a target, it is possible to suppress the features of a known distractor. This suppression may prevent distractor processing altogether or only after the distractor initially captures attention (i.e., search and destroy). However, suppression may be impaired in individuals with attentional control deficits, such as in high anxiety. In this study (n = 48), we used ERPs to examine the time course of attentional enhancement and suppression when participants were given pretrial information about target or distractor features. Consistent with our hypothesis, we found that individuals with higher levels of anxiety had lower neural measures of suppressing the template-matching distractor, instead showing enhanced processing. These findings indicate that individuals with anxiety are more likely to use a search-and-destroy mechanism of negative templates-highlighting the importance of attentional control abilities in distractor-guided search., (© 2021 Massachusetts Institute of Technology.)

This protocol outlines steps to visualize and detect Ca 2+ puffs following photo-liberation of caged inositol-1,4,5-trisphosphate (IP 3 ) from HEK-293 cells expressing only the native IP 3 R type 1 receptor using total internal reflection fluorescence (TIRF) microscopy. TIRF microscopy offers high axial resolution and allows imaging at high speed, with a higher signal-to-background ratio. Additionally, we shed light on commonly encountered pitfalls, which should be considered while recording Ca 2+ puffs using TIRF microscopy. For complete details on the use and execution of this protocol, please refer to Emrich et al. (2021) and Lock et al. (2015a)., Competing Interests: The authors declare no competing interests., (© 2021 The Author(s).)

Stromal-interaction molecules (STIM1/2) sense endoplasmic reticulum (ER) Ca 2+ depletion and activate Orai channels. However, the choreography of interactions between native STIM/Orai proteins under physiological agonist stimulation is unknown. We show that the five STIM1/2 and Orai1/2/3 proteins are non-redundant and function together to ensure the graded diversity of mammalian Ca 2+ signaling. Physiological Ca 2+ signaling requires functional interactions between STIM1/2, Orai1/2/3, and IP 3 Rs, ensuring that receptor-mediated Ca 2+ release is tailored to Ca 2+ entry and nuclear factor of activated T cells (NFAT) activation. The N-terminal Ca 2+ -binding ER-luminal domains of unactivated STIM1/2 inhibit IP 3 R-evoked Ca 2+ release. A gradual increase in agonist intensity and STIM1/2 activation relieves IP 3 R inhibition. Concomitantly, activated STIM1/2 C termini differentially interact with Orai1/2/3 as agonist intensity increases. Thus, coordinated and omnitemporal functions of all five STIM/Orai and IP 3 Rs translate the strength of agonist stimulation to precise levels of Ca 2+ signaling and NFAT induction, ensuring the fidelity of complex mammalian Ca 2+ signaling., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Individuals with anxiety have attentional biases toward threat-related distractors. This deficit in attentional control has been shown to impact visual working memory (VWM) filtering efficiency, as anxious individuals inappropriately store threatening distractors in VWM. It remains unclear, however, whether this mis-allocation of memory resources is due to inappropriate attentional enhancement of threatening distractors, or to a failure in suppression. Here, we used a systematically lateralized VWM task with fearful and neutral faces to examine event-related potentials related to attentional selection (N2pc), suppression (P D ), and working memory maintenance (CDA). We found that state anxiety correlated with attentional enhancement of threat-related distractors, such that more anxious individuals had larger N2pc amplitudes toward fearful distractors than neutral distractors. However, there was no correlation between anxiety and memory storage of fearful distractors (CDA). These findings demonstrate that anxiety biases attention toward fearful distractors, but that this bias does not always guarantee increased memory storage of threat-related distractors.

The ubiquitous Ca 2+ release-activated Ca 2+ (CRAC) channel is crucial to many physiological functions. Both gain and loss of CRAC function is linked to disease. While ORAI1 is a crucial subunit of CRAC channels, recent evidence suggests that ORAI2 and ORAI3 heteromerize with ORAI1 to form native CRAC channels. Furthermore, ORAI2 and ORAI3 can form CRAC channels independently of ORAI1, suggesting diverse native CRAC stoichiometries. Yet, most available CRAC modifiers are presumed to target ORAI1 with little knowledge of their effects on ORAI2/3 or heteromers of ORAIs. Here, we used ORAI1/2/3 triple-null cells to express individual ORAI1, ORAI2, ORAI3 or ORAI1/2/3 concatemers. We reveal that GSK-7975A and BTP2 essentially abrogate ORAI1 and ORAI2 activity while causing only a partial inhibition of ORAI3. Interestingly, Synta66 abrogated ORAI1 channel function, while potentiating ORAI2 with no effect on ORAI3. CRAC channel activities mediated by concatenated ORAI1-1, ORAI1-2 and ORAI1-3 dimers were inhibited by Synta66, while ORAI2-3 dimers were unaffected. The CRAC enhancer IA65 significantly potentiated ORAI1 and ORAI1-1 activity with marginal effects on other ORAIs. Further, we characterized the profiles of individual ORAI isoforms in the presence of Gd 3+ (5μM), 2-APB (5 μM and 50 μM), as well as changes in intracellular and extracellular pH. Our data reveal unique pharmacological features of ORAI isoforms expressed in an ORAI-null background and provide new insights into ORAI isoform selectivity of widely used CRAC pharmacological compounds., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The ubiquitous store-operated Ca 2+ entry pathway mediated by plasma membrane Ca 2+ release-activated Ca 2+ (CRAC) channels regulates a wide variety of physiological functions. While it is clearly established that the ORAI1 protein is essential for native mammalian CRAC channels, the contribution of ORAI2 and ORAI3 have remained nebulous. The crystal structure of the sole Orai isoform in drosophila ( dOrai ) revealed a hexameric assembly, suggesting that mammalian CRAC channels are hexamers of ORAI. Nevertheless, the relative contribution of each isoform of the mammalian ORAI trio to the stoichiometry of native CRAC channels remains elusive. The recent generation of ORAI isoform single, double and triple knockout cell lines and tissue-specific knockout mice has shed light on how native ORAI isoform heteromerization fine tunes CRAC-mediated Ca 2+ signaling., Competing Interests: CONFLICT OF INTEREST STATEMENT The authors declare no competing interests.

Despite the established role of mitochondria in cancer, the mechanisms by which mitochondrial Ca 2+ (mtCa 2+ ) regulates tumorigenesis remain incompletely understood. The crucial role of mtCa 2+ in tumorigenesis is highlighted by altered expression of proteins mediating mtCa 2+ uptake and extrusion in cancer. Here, we demonstrate decreased expression of the mitochondrial Na + /Ca 2+ /Li + exchanger NCLX ( SLC8B1 ) in human colorectal tumors and its association with advanced-stage disease in patients. Downregulation of NCLX causes mtCa 2+ overload, mitochondrial depolarization, decreased expression of cell-cycle genes and reduced tumor size in xenograft and spontaneous colorectal cancer mouse models. Concomitantly, NCLX downregulation drives metastatic spread, chemoresistance, and expression of epithelial-to-mesenchymal, hypoxia, and stem cell pathways. Mechanistically, mtCa 2+ overload leads to increased mitochondrial reactive oxygen species, which activate HIF1α signaling supporting metastasis of NCLX-null tumor cells. Thus, loss of NCLX is a novel driver of metastasis, indicating that regulation of mtCa 2+ is a novel therapeutic approach in metastatic colorectal cancer., Competing Interests: TP, MG, VW, CD, MJ, XZ, PX, RY, SE, GY, IS, WK, DG, NH, MT No competing interests declared, (© 2020, Pathak et al.)

Visual working memory (VWM) resources have been shown to be flexibly distributed according to item priority. This flexible allocation of resources may depend on attentional control, an executive function known to decline with age. In this study, we sought to determine how age differences in attentional control affect VWM performance when attention is flexibly allocated amongst targets of varying priority. Participants performed a delayed-recall task wherein item priority was varied. Error was modelled using a three-component mixture model to probe different aspects of performance (precision, guess-rate, and non-target errors). The flexible resource model offered a good fit to the data from both age groups, but older adults showed consistently lower precision and higher guess rates. Importantly, when demands on flexible resource allocation were highest, older adults showed more non-target errors, often swapping in the item that had a higher priority at encoding. Taken together, these results suggest that the ability to flexibly allocate attention in VWM is largely maintained with age, but older adults are less precise overall and sometimes swap in salient, but no longer relevant, items possibly due to their lessened ability to inhibit previously attended information.

Voltage-gated L-type Ca 2+ channel (Ca v 1.2) blockers (LCCBs) are major drugs for treating hypertension, the preeminent risk factor for heart failure. Vascular smooth muscle cell (VSMC) remodeling is a pathological hallmark of chronic hypertension. VSMC remodeling is characterized by molecular rewiring of the cellular Ca 2+ signaling machinery, including down-regulation of Ca v 1.2 channels and up-regulation of the endoplasmic reticulum (ER) stromal-interacting molecule (STIM) Ca 2+ sensor proteins and the plasma membrane ORAI Ca 2+ channels. STIM/ORAI proteins mediate store-operated Ca 2+ entry (SOCE) and drive fibro-proliferative gene programs during cardiovascular remodeling. SOCE is activated by agonists that induce depletion of ER Ca 2+ , causing STIM to activate ORAI. Here, we show that the three major classes of LCCBs activate STIM/ORAI-mediated Ca 2+ entry in VSMCs. LCCBs act on the STIM N terminus to cause STIM relocalization to junctions and subsequent ORAI activation in a Ca v 1.2-independent and store depletion-independent manner. LCCB-induced promotion of VSMC remodeling requires STIM1, which is up-regulated in VSMCs from hypertensive rats. Epidemiology showed that LCCBs are more associated with heart failure than other antihypertensive drugs in patients. Our findings unravel a mechanism of LCCBs action on Ca 2+ signaling and demonstrate that LCCBs promote vascular remodeling through STIM-mediated activation of ORAI. Our data indicate caution against the use of LCCBs in elderly patients or patients with advanced hypertension and/or onset of cardiovascular remodeling, where levels of STIM and ORAI are elevated., Competing Interests: The authors declare no competing interest.

The essential role of ORAI1 channels in receptor-evoked Ca 2+ signaling is well understood, yet little is known about the physiological activation of the ORAI channel trio natively expressed in all cells. The roles of ORAI2 and ORAI3 have remained obscure. We show that ORAI2 and ORAI3 channels play a critical role in mediating the regenerative Ca 2+ oscillations induced by physiological receptor activation, yet ORAI1 is dispensable in generation of oscillations. We reveal that ORAI2 and ORAI3 channels multimerize with ORAI1 to expand the range of sensitivity of receptor-activated Ca 2+ signals, reflecting their enhanced basal STIM1-binding and heightened Ca 2+ -dependent inactivation. This broadened bandwidth of Ca 2+ influx is translated by cells into differential activation of NFAT1 and NFAT4 isoforms. Our results uncover a long-sought role for ORAI2 and ORAI3, revealing an intricate control mechanism whereby heteromerization of ORAI channels mediates graded Ca 2+ signals that extend the agonist-sensitivity to fine-tune transcriptional control.

Visual working memory is a brief, capacity-limited store of visual information that is involved in a large number of cognitive functions. To guide one's behavior effectively, one must efficiently allocate these limited memory resources across memory items. Previous research has suggested that items are either stored in memory or completely blocked from memory access. However, recent behavioral work proposes that memory resources can be flexibly split across items based on their level of task importance. Here, we investigated the electrophysiological correlates of flexible resource allocation by manipulating the distribution of resources amongst systematically lateralized memory items. We examined the contralateral delay activity (CDA), a waveform typically associated with the number of items held in memory. Across three experiments, we found that, in addition to memory load, the CDA flexibly tracks memory resource allocation. This allocation occurred as early as attentional selection, as indicated by the N2pc. Additionally, CDA amplitude was better-described when fit with a continuous model predicted by load and resources together than when fit with either alone. Our findings show that electrophysiological markers of attentional selection and memory maintenance not only track memory load, but also the proportion of memory resources those items receive.

Store-operated Ca 2+ entry (SOCE) is a ubiquitous pathway for Ca 2+ influx across the plasma membrane (PM). SOCE is mediated by the endoplasmic reticulum (ER)-associated Ca 2+ -sensing proteins stromal interaction molecule 1 (STIM1) and STIM2, which transition into an active conformation in response to ER Ca 2+ store depletion, thereby interacting with and gating PM-associated ORAI1 channels. Although structurally homologous, STIM1 and STIM2 generate distinct Ca 2+ signatures in response to varying strengths of agonist stimulation. The physiological functions of these Ca 2+ signatures, particularly under native conditions, remain unclear. To investigate the structural properties distinguishing STIM1 and STIM2 activation of ORAI1 channels under native conditions, here we used CRISPR/Cas9 to generate STIM1 -/- , STIM2 -/- , and STIM1/2 -/- knockouts in HEK293 and colorectal HCT116 cells. We show that depending on cell type, STIM2 can significantly sustain SOCE in response to maximal store depletion. Utilizing the SOCE modifier 2-aminoethoxydiphenyl borate (2-APB), we demonstrate that 2-APB-activated store-independent Ca 2+ entry is mediated exclusively by endogenous STIM2. Using variants that either stabilize or disrupt intramolecular interactions of STIM C termini, we show that the increased flexibility of the STIM2 C terminus contributes to its selective store-independent activation by 2-APB. However, STIM1 variants with enhanced flexibility in the C terminus failed to support its store-independent activation. STIM1/STIM2 chimeric constructs indicated that coordination between N-terminal sensitivity and C-terminal flexibility is required for specific store-independent STIM2 activation. Our results clarify the structural determinants underlying activation of specific STIM isoforms, insights that are potentially useful for isoform-selective drug targeting.

Working memory (WM) is impaired following sleep loss and may be improved after a nap. The goal of the current study was to better understand sleep-related WM enhancement by: (1) employing a WM task that assesses the ability to hold and report visual representations as well as the fidelity of the reports on a fine scale, (2) investigating neurophysiological properties of sleep and WM capacity as potential predictors or moderators of sleep-related enhancement, and (3) exploring frontal and occipital event-related delay activity to index the neural processing of stimuli in WM. In a within-subjects design, 36 young adults (M age = 20, 20 men, 16 women) completed a 300-trial, continuous-report task of visual WM following a 90-min nap opportunity and an equivalent period of wakefulness. Mixed-effect models were used to estimate the odds of successful WM reports and the fidelity of those reports. The odds of a successful report were approximately equal between nap and wake conditions for the start of the task, but by the end, the odds of success were 1.26 times greater in the nap condition. Successful WM reports were more accurate after a nap, independent of the time on task. Neither WM capacity nor any of the sleep variables measured were found to significantly moderate the nap effect on WM. Lastly, napping resulted in amplitude changes for frontal and occipital delay activity relative to the wake condition. The findings are discussed in relation to contemporary models of visual WM and the role of sleep in sustained attention.

Other-race faces are discriminated and recognized less accurately than own-race faces. Despite a wealth of research characterizing this other-race effect (ORE), little is known about the nature of the representations of own-race versus other-race faces. This is because traditional measures of this ORE provide a binary measure of discrimination or recognition (correct/incorrect), failing to capture potential variation in the quality of face representations. We applied a novel continuous-response paradigm to independently measure the number of own-race and other-race face representations stored in visual working memory (VWM) and the precision with which they are stored. Participants reported target own-race or other-race faces on a circular face space that smoothly varied along the dimension of identity. Using probabilistic mixture modeling, we found that following ample encoding time, the ORE is attributable to differences in the probability of a face being maintained in VWM. Reducing encoding time, a manipulation that is more sensitive to encoding limitations, caused a loss of precision or an increase in variability of VWM for other-race but not own-race faces. These results suggest that the ORE is driven by the inefficiency with which other-race faces are rapidly encoded in VWM and provide novel insights about how perceptual experience influences the representation of own-race and other-race faces in VWM.

To keep track of dynamically changing objects in one's environment, it is necessary to individuate them from other objects, both temporally and spatially. Spatially, objects can be selected from nearby distractors using selective attention. Temporally, object updating processes incorporate new information into existing representations over time. Both of these processes have been implicated in a type of visual masking called object-substitution masking (OSM). Previous studies have found that the number of distractors (impacting selective attention) interacts with the strength of OSM. However, it has been suggested that this interaction is an artifact of ceiling performance at low set sizes, rather than necessitating a failure of attention during masking. Using event-related potentials (ERPs), we examined whether set size and masking interact as measured by markers of selective attention (N2pc) and visual working memory consolidation/maintenance (SPCN). Set size was found to affect the N2pc (200-350 ms) and late SPCN (500-650 ms), reflecting increased demands on selective attention and unnecessary storage respectively. An early window of the SPCN (350-500 ms) was affected by masking, suggesting that OSM influences object consolidation processes in this window, independent of the number of distractors. Overall, it was found that selective attention and visual awareness are dissociable neural processes in OSM, and that they are independently affected by set size and masking manipulations. Moreover, we found that the early SPCN may reflect disruptions to object consolidation, potentially revealing a neural mechanism supporting an object individuation-through-updating account of OSM.

A long-standing assumption of cognitive neuroscience has been that working memory (WM) is accomplished by sustained, elevated neural activity. More recently, theories of WM have expanded this view by describing different attentional states in WM with differing activation levels. Several studies have used multivariate pattern analysis (MVPA) of functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) data to study neural activity corresponding to these WM states. Intriguingly, no evidence was found for active neural representations for information held in WM outside the focus of attention ("unattended memory items," UMIs), suggesting that only attended memory items (AMIs) are accompanied by an active trace. However, these results depended on category-level decoding, which lacks sensitivity to neural representations of individual items. Therefore, we employed a WM task in which subjects remembered the directions of motion of two dot arrays, with a retrocue indicating which was relevant for an imminent memory probe (the AMI). This design allowed MVPA decoding of delay-period fMRI signal at the stimulus-item level, affording a more sensitive test of the neural representation of UMIs. Whereas evidence for the AMI was reliably high, evidence for the UMI dropped to baseline, consistent with the notion that different WM attentional states may have qualitatively different mechanisms of retention., (© The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Across 2 experiments we revisited the filter account of how feature-based attention regulates visual working memory (VWM). Originally drawing from discrete-capacity ("slot") models, the filter account proposes that attention operates like the "bouncer in the brain," preventing distracting information from being encoded so that VWM resources are reserved for relevant information. Given recent challenges to the assumptions of discrete-capacity models, we investigated whether feature-based attention plays a broader role in regulating memory. Both experiments used partial report tasks in which participants memorized the colors of circle and square stimuli, and we provided a feature-based goal by manipulating the likelihood that 1 shape would be probed over the other across a range of probabilities. By decomposing participants' responses using mixture and variable-precision models, we estimated the contributions of guesses, nontarget responses, and imprecise memory representations to their errors. Consistent with the filter account, participants were less likely to guess when the probed memory item matched the feature-based goal. Interestingly, this effect varied with goal strength, even across high probabilities where goal-matching information should always be prioritized, demonstrating strategic control over filter strength. Beyond this effect of attention on which stimuli were encoded, we also observed effects on how they were encoded: Estimates of both memory precision and nontarget errors varied continuously with feature-based attention. The results offer support for an extension to the filter account, where feature-based attention dynamically regulates the distribution of resources within working memory so that the most relevant items are encoded with the greatest precision. (PsycINFO Database Record, ((c) 2017 APA, all rights reserved).)

Though it is clear that it is impossible to store an unlimited amount of information in visual working memory (VWM), the limiting mechanisms remain elusive. While several models of VWM limitations exist, these typically characterize changes in performance as a function of the number of to-be-remembered items. Here, we examine whether changes in spatial attention could better account for VWM performance, independent of load. Across 2 experiments, performance was better predicted by the prioritization of memory items (i.e., attention) than by the number of items to be remembered (i.e., memory load). This relationship followed a power law, and held regardless of whether performance was assessed based on overall precision or any of 3 measures in a mixture model. Moreover, at large set sizes, even minimally attended items could receive a small proportion of resources, without any evidence for a discrete-capacity on the number of items that could be maintained in VWM. Finally, the observed data were best fit by a variable-precision model in which response error was related to the proportion of resources allocated to each item, consistent with a model of VWM in which performance is determined by the continuous allocation of attentional resources during encoding. (PsycINFO Database Record, ((c) 2017 APA, all rights reserved).)

Numerous studies have demonstrated that visual STM (VSTM) and attention are tightly linked processes that share a number of neuroanatomical substrates. Here, we used repetitive TMS (rTMS) along with simultaneous EEG to examine the causal relationship between intraparietal sulcus functioning and performance on tasks of attention and VSTM. Participants performed two tasks in which they were required to attend to or remember colored items over a brief interval, with 10-Hz rTMS applied on some of the trials. Although no overall behavioral changes were observed across either task, rTMS did affect individual performance on both the attention and VSTM tasks in a manner that was predicted by individual differences in baseline performance. Furthermore, rTMS also affected ongoing oscillations in the alpha and beta bands, and these changes were related to the observed change in behavioral performance. The results reveal a causal relationship between intraparietal sulcus activity and tasks measuring both visual attention and VSTM.

Studies of consciousness reveal that it is possible to manipulate subjective awareness of a visual stimulus. For example, items held in visual working memory (VWM) that match target features increase the speed with which the target reaches visual awareness. To examine the effect of VWM on perception, previous studies have mainly used coarse measures of awareness, such as present/absent or forced-choice judgments. These methods can reveal whether or not an individual has seen an item, but they do not provide information about the quality with which the item was seen. Using continuous report methods it has been shown that the fidelity of a perceived item can be affected by whether or not that item is masked. In the present study, we used an object-substitution masking task to examine whether items held in VWM would influence the quality with which a masked target reached awareness, or whether the threshold for awareness was instead affected by stimuli held in memory. We observed that targets matching the contents of VWM were recalled with greater precision compared to items that did not match the contents of VWM. Importantly, this effect occurred without affecting the likelihood of the target being perceived. These results suggest that VWM plays a greater role in modulating the fidelity of perceived representations than in lowering the overall threshold of awareness.

During visual search, visual working memory (VWM) supports the guidance of attention in two ways: It stores the identity of the search target, facilitating the selection of matching stimuli in the search array, and it maintains a record of the distractors processed during search so that they can be inhibited. In two experiments, we investigated whether the full contents of VWM can be used to support both of these abilities simultaneously. In Experiment 1, participants completed a preview search task in which (a) a subset of search distractors appeared before the remainder of the search items, affording participants the opportunity to inhibit them, and (b) the search target varied from trial to trial, requiring the search target template to be maintained in VWM. We observed the established signature of VWM-based inhibition-reduced ability to ignore previewed distractors when the number of distractors exceeds VWM's capacity-suggesting that VWM can serve this role while also representing the target template. In Experiment 2, we replicated Experiment 1, but added to the search displays a singleton distractor that sometimes matched the color (a task-irrelevant feature) of the search target, to evaluate capture. We again observed the signature of VWM-based preview inhibition along with attentional capture by (and, thus, facilitation of) singletons matching the target template. These findings indicate that more than one VWM representation can bias attention at a time, and that these representations can separately affect selection through either facilitation or inhibition, placing constraints on existing models of the VWM-based guidance of attention.

The amount of task-irrelevant information encoded in visual working memory (VWM), referred to as unnecessary storage, has been proposed as a potential mechanism underlying individual differences in VWM capacity. In addition, a number of studies have provided evidence for additional activity that initiates the filtering process originating in the frontal cortex and basal ganglia, and is therefore a crucial step in the link between unnecessary storage and VWM capacity. Here, we re-examine data from two prominent studies that identified unnecessary storage activity as a predictor of VWM capacity by directly testing the implied path model linking filtering-related activity, unnecessary storage, and VWM capacity. Across both studies, we found that unnecessary storage was not a significant predictor of individual differences in VWM capacity once activity associated with filtering was accounted for; instead, activity associated with filtering better explained variation in VWM capacity. These findings suggest that unnecessary storage is not a limiting factor in VWM performance, whereas neural activity associated with filtering may play a more central role in determining VWM performance that goes beyond preventing unnecessary storage.

When a test of working memory (WM) requires the retention of multiple items, a subset of them can be prioritized. Recent studies have shown that, although prioritized (i.e., attended) items are associated with active neural representations, unprioritized (i.e., unattended) memory items can be retained in WM despite the absence of such active representations, and with no decrement in their recognition if they are cued later in the trial. These findings raise two intriguing questions about the nature of the short-term retention of information outside the focus of attention. First, when the focus of attention shifts from items in WM, is there a loss of fidelity for those unattended memory items? Second, could the retention of unattended memory items be accomplished by long-term memory mechanisms? We addressed the first question by comparing the precision of recall of attended versus unattended memory items, and found a significant decrease in precision for unattended memory items, reflecting a degradation in the quality of those representations. We addressed the second question by asking subjects to perform a WM task, followed by a surprise memory test for the items that they had seen in the WM task. Long-term memory for unattended memory items from the WM task was not better than memory for items that had remained selected by the focus of attention in the WM task. These results show that unattended WM representations are degraded in quality and are not preferentially represented in long-term memory, as compared to attended memory items.

Although long considered a natively endowed and fixed trait, working memory (WM) ability has recently been shown to improve with intensive training. What remains controversial and poorly understood, however, are the neural bases of these training effects and the extent to which WM training gains transfer to other cognitive tasks. Here we present evidence from human electrophysiology (EEG) and simultaneous transcranial magnetic stimulation and EEG that the transfer of WM training to other cognitive tasks is supported by changes in task-related effective connectivity in frontoparietal and parieto-occipital networks that are engaged by both the trained and transfer tasks. One consequence of this effect is greater efficiency of stimulus processing, as evidenced by changes in EEG indices of individual differences in short-term memory capacity and in visual search performance. Transfer to search-related activity provides evidence that something more fundamental than task-specific strategy or stimulus-specific representations has been learned. Furthermore, these patterns of training and transfer highlight the role of common neural systems in determining individual differences in aspects of visuospatial cognition.

Traditionally, load sensitivity of sustained, elevated activity has been taken as an index of storage for a limited number of items in visual short-term memory (VSTM). Recently, studies have demonstrated that the contents of a single item held in VSTM can be decoded from early visual cortex, despite the fact that these areas do not exhibit elevated, sustained activity. It is unknown, however, whether the patterns of neural activity decoded from sensory cortex change as a function of load, as one would expect from a region storing multiple representations. Here, we use multivoxel pattern analysis to examine the neural representations of VSTM in humans across multiple memory loads. In an important extension of previous findings, our results demonstrate that the contents of VSTM can be decoded from areas that exhibit a transient response to visual stimuli, but not from regions that exhibit elevated, sustained load-sensitive delay-period activity. Moreover, the neural information present in these transiently activated areas decreases significantly with increasing load, indicating load sensitivity of the patterns of activity that support VSTM maintenance. Importantly, the decrease in classification performance as a function of load is correlated with within-subject changes in mnemonic resolution. These findings indicate that distributed patterns of neural activity in putatively sensory visual cortex support the representation and precision of information in VSTM.

In four experiments we assessed whether visual working memory (VWM) maintains a record of previously processed visual information, allowing old information to be inhibited, and new information to be prioritized. Specifically, we evaluated whether VWM contributes to the inhibition (i.e., visual marking) of previewed distractors in a preview search. We evaluated this proposal by testing three predictions. First, Experiments 1 and 2 demonstrate that preview inhibition is more effective when the number of previewed distractors is below VWM capacity than above; an effect that can only be observed at small preview set sizes (Experiment 2A) and when observers are allowed to move their eyes freely (Experiment 2B). Second, Experiment 3 shows that, when quantified as the number of inhibited distractors, the magnitude of the preview effect is stable across different search difficulties. Third, Experiment 4 demonstrates that individual differences in preview inhibition are correlated with individual differences in VWM capacity. These findings provide converging evidence that VWM supports the inhibition of previewed distractors. More generally, these findings demonstrate how VWM contributes to the efficiency of human visual information processing--VWM prioritizes new information by inhibiting old information from being reselected for attention.

Although significant advances in our understanding of the cognitive and neural processes involved in conscious awareness have occurred in recent years, the precise mechanisms that support consciousness remain elusive. Examining the neural correlates associated with the moment a stimulus enters or exits conscious awareness is one way to potentially identify the neural mechanisms that give rise to consciousness. In the present study, we recorded neural activity using electroencephalography (EEG) while participants observed a bilateral shape-from-motion (SFM) display. While the display is in motion, the observer perceives an object that is immediately segregated from a noisy background. After the motion stops, the observer's experience of the object remains momentarily in awareness, before it eventually fades out of consciousness back into the noisy background. Consistent with subjective reports of perceptual experience, we observed a prominent sustained posterior contralateral negativity known as the contralateral delay activity (CDA). This activity was sustained only in conditions associated with sustained awareness. Interestingly, the amplitude of the CDA was correlated with individual differences in visual awareness, suggesting that this activity plays a significant role in the maintenance of objects in consciousness. The CDA is typically associated with visual short-term memory (VSTM), suggesting that conscious visual awareness may be mediated by the same neural and cognitive mechanisms that support VSTM. Our results demonstrate that the CDA may reflect the contents of conscious awareness, and therefore can provide a measure to track when information moves in and out of consciousness.

When faced with maintaining multiple objects in visual working memory, item information must be bound to the correct object in order to be correctly recalled. Sometimes, however, binding errors occur, and participants report the feature (e.g., color) of an unprobed, non-target item. In the present study, we examine whether the configuration of sample stimuli affects the proportion of these binding errors. The results demonstrate that participants mistakenly report the identity of the unprobed item (i.e., they make a non-target response) when sample items are presented close together in space, suggesting that binding errors can increase independent of increases in memory load. Moreover, the proportion of these non-target responses is linearly related to the distance between sample items, suggesting that these errors are spatially specific. Finally, presenting sample items sequentially decreases non-target responses, suggesting that reducing competition between sample stimuli reduces the number of binding errors. Importantly, these effects all occurred without increases in the amount of error in the memory representation. These results suggest that competition during encoding can account for some of the binding errors made during VWM recall.

Visual working memory (VWM) is a capacity-limited cognitive resource that plays an important role in complex cognitive behaviors. Recent studies indicate that regions subserving VWM may play a role in the perception and recognition of visual objects, suggesting that conscious object perception may depend on the same cognitive and neural architecture that supports the maintenance of visual object information. In the present study, we examined this question by testing object processing under a concurrent VWM load. Under a high VWM load, recognition was impaired for objects presented in the left visual field, in particular when two objects were presented simultaneously. Multivariate fMRI revealed that two independent but partially overlapping networks of brain regions contribute to object recognition. The first network consisted of regions involved in VWM encoding and maintenance. Importantly, these regions were also sensitive to object load. The second network comprised regions of the ventral temporal lobes traditionally associated with object recognition. Importantly, activation in both networks predicted object recognition performance. These results indicate that information processing in regions that mediate VWM may be critical to conscious visual perception. Moreover, the observation of a hemifield asymmetry in object recognition performance has important theoretical and clinical significance for the study of visual neglect.

There is now substantial evidence that during visual search, previously searched distractors are stored in memory to prevent them from being reselected. Studies examining which memory resources are involved in this process have indicated that while a concurrent spatial working memory task does affect search slopes, depleting visual working memory (VWM) resources does not. In the present study, we confirm that VWM load indeed has no effect on the search slope; however, there is an increase in overall reaction times that is directly related to the number of items held in VWM. Importantly, this effect on search time increases proportionally with the memory load until the capacity of VWM is reached. Furthermore, the search task interfered with the number of items stored in VWM during the concurrent change-detection task. These findings suggest that VWM plays a role in the inhibition of previously searched distractors.

Background: Although limited in capacity, visual working memory (VWM) plays an important role in many aspects of visually-guided behavior. Recent experiments have demonstrated an electrophysiological marker of VWM encoding and maintenance, the contralateral delay activity (CDA), which has been shown in multiple tasks that have both explicit and implicit memory demands. Here, we investigate whether the CDA is evident during visual search, a thoroughly-researched task that is a hallmark of visual attention but has no explicit memory requirements., Methodology/principal Findings: The results demonstrate that the CDA is present during a lateralized search task, and that it is similar in amplitude to the CDA observed in a change-detection task, but peaks slightly later. The changes in CDA amplitude during search were strongly correlated with VWM capacity, as well as with search efficiency. These results were paralleled by behavioral findings showing a strong correlation between VWM capacity and search efficiency., Conclusions/significance: We conclude that the activity observed during visual search was generated by the same neural resources that subserve VWM, and that this activity reflects the maintenance of previously searched distractors.

If some of the distractors in a visual search task are previewed prior to the presentation of the remaining distractors and the target, search time is reduced relative to when all of the items are displayed simultaneously. Here, we tested whether the ability to preferentially search new items during such a preview search is limited. We confirmed previous studies: The proportion of fixations on old items was significantly less than chance. However, the probability of fixating old locations was negatively affected by increasing the number of previewed distractors, suggesting that inhibition is limited to a small number of old items. Furthermore, the ability to inhibit old locations was limited to the first four fixations, indicating that by the fifth fixation, the resources required to sustain inhibition had been depleted. Together, these findings suggest that inhibition of old items in a preview search is a top-down mediated process dependent on capacity-limited cognitive resources.

When a fragmented line-drawing of an object moves relative to a background of randomly oriented lines, the previously hidden object can be segregated from the background and consequently enters awareness. In this shape-from-motion paradigm, the percept of the object briefly persists after the motion stops, demonstrating the maintenance of a bound percept in awareness. This study investigated how the manipulation of object features that are crucial to recognition influences both the binding process and the maintenance of objects in awareness. Overall, we found that objects that took longer to recognize (i.e., objects missing their vertices) were nonetheless maintained in awareness for longer. We argue that this effect is mediated by additional elaborative processing that is required to bind these less recognizable forms, which generates stronger and more robust representations. These representations are then more easily maintained in awareness, suggesting an important role of elaborative mechanisms for conscious representations.