Mediated Priming Research Articles

Redox-active ash gourd extract mitigates salt-stress toxicity through modulation of primary metabolites in rice

Salinity stress is considered as one of the major detrimental stresses for reducing plant growth and crop productivity. Hence, concerted efforts are going on to develop sustainable solutions for reducing salinity-induced negative effects on crop productivity. Given this, the present study evaluated the potential of ash gourd extract (AGE; 0.9 µg/mL) for ameliorating NaCl (100 mM) stress in rice, which is one of the major staple food crops worldwide. The differential phenotyping revealed growth reduction under NaCl treatment, as indicated by 0.27- and 0.36-fold decrease in survival and whole-seedling biomass, respectively, compared with those of control. In contrast, 24 h pre-treatment with AGE before NaCl exposure (AGE24h+NaCl) improved these growth attributes by 1.29- and 1.70-fold, respectively, compared with those of NaCl treatment. The differential phenotype of AGE was associated with its inherent ability to scavenge reactive oxygen species, which was equivalent to 0.08-fold of ascorbic acid. The higher accumulation of superoxide radicals and upregulated expression of stress marker genes including OsTSPO, OsCBS, OsHKT1;5, and OsNHX1 under AGE24h treatment also suggested AGE mediated priming effect. Under AGE24h+NaCl, the expression levels of these stress markers were either maintained or their extent of upregulation was further enhanced. In addition, the coordinated activation of antioxidant machinery and reduced Na-accumulation further supported stress amelioration under AGE24h+NaCl treatment. GC-MS-based metabolomics highlighted fatty acids, malic acid, myo-inositol, allose, trehalose, and L-oxoproline, as key metabolites, associated with AGE-mediated amelioration of NaCl stress. The foliar application of AGE increased seed yield and 1000 seed weight by 1.13- and 1.06-fold, respectively, compared with those of NaCl, validating its agronomic feasibility. Thus, the results highlighted the application of AGE, as a “green” bioregulator for ameliorating NaCl stress conditions in rice.

Influence of Psychological Vulnerability Factors for Bipolar Disorders on a Semantic Mediated Priming Task.

Hypomanic personality, hyperthymic temperament and irritable temperament are considered as psychological vulnerability factors to bipolar disorders. Semantic memory is impaired in bipolar patients. Spreading activation is among the probable candidates for accounting this impairment. The aim of this study was to assess spreading activation according to vulnerability factors continuum to determine whether it could be a factor of vulnerability to bipolar disorders. A sample of 61 healthy volunteers was recruited. Spreading activation was assessed by semantic mediated priming implemented in a double lexical decision task. Results shown that semantic mediated priming was negatively associated to hyperthymic temperament and irritable temperament. Impairment in semantic memory, and more specifically spreading activation, appear to be a cognitive factor of vulnerability to bipolar disorders. Our results can contribute to a better understanding of semantic impairment in vulnerable population and in bipolar disorder.

Mediated semantic priming interference in toddlers as seen through pupil dynamics

Mediated priming refers to the activation of a target word by a prime word through an intermediate word. This type of priming provides behavioral evidence of between- and within-level spreading activation in the lexical system. Studies of toddlers show phonosemantic between-level mediated priming that supports a cascade of activation between different levels of processing. However, it is not clear whether the activation can spread freely within the same level. This study explored whether 24-month-old toddlers show mediated priming effects at the semantic level (e.g., cat [prime] – mouse [mediator] – cheese [target]) with a preferential looking task using an eye tracker. The results show a smaller proportion of target looking and greater pupil size in the related condition than in the unrelated condition; these effects were greater in the second half of the analysis window. We interpret these data as a spreading activation that is partially free but modulated during infancy. We also provide evidence of pupil dilation as a neurophysiological marker in a preferential looking task with priming. We discuss the results in light of the cognitive control, inhibition, and general cognitive skills of toddlers.

Abstract LB-052: Photochemistry mediated tumor priming potentiates cytoreduction of distant metastases to enable potential surgical cure in a late stage model of pancreas cancer

Abstract Pancreatic cancer is a devastating disease for which the 5 year survival rate remains < 10% despite years of concerted research efforts. Potentially curative surgical resection cannot even be offered to most patients due to the presence of distant metastases at the time of diagnosis. Here, we present a neoadjuvant strategy comprised of photochemistry mediated tumor modulation combined with systemic therapy to significantly cytoreduce, and in 50% of cases completely eliminate, distant metastases to create a window of potential resectability. In a late stage model of pancreas cancer in which distant metastases are present at the time of treatment, combined photodynamic therapy (PDT) and gemcitabine/abraxane led to a 10,000 fold decrease in the number of distant metastases compared to untreated controls. In comparison, gemcitabine + abraxane, the current standard of care for pancreas cancer, only led to a 100 fold cytoreduction. 50% of animals treated with PDT + gem/abraxane harbored no detectable metastases 51 days after treatment compared to 0% of gem/abraxane treated animals, suggesting that PDT plus cytoreduction could enable potentially curative surgery in a sizeable percentage of animals. The strategy presented here is rapidly translatable and holds significant promise to dramatically increase the percentage of patients that are currently eligible for curative therapy for this devastating disease. Citation Format: Sriram Anbil, Zhiming Mai, Michael Pigula, Tayyaba Hasan. Photochemistry mediated tumor priming potentiates cytoreduction of distant metastases to enable potential surgical cure in a late stage model of pancreas cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-052.

Phonological activation of category coordinates in spoken word production: Evidence for cascaded processing in English but not in Mandarin

ABSTRACTA central issue in spoken word production concerns how activation is transmitted from semantic to phonological levels. Recent evidence from studies of speakers of Western languages supports a cascaded view, according to which under certain circumstances, lexical candidates other than the target can activate their corresponding phonological properties. In the current study, we investigated possible differences between English and Mandarin speakers concerning the degree of cascadedness in the production system, based on the broader recent claim that properties of word form encoding might differ according to languages. With English speakers (Experiment 1), we found that when activation of targets and semantic competitors was boosted via a manipulation of semantic context, then concurrently presented “mediated” distractor words (which were phonologically related to a semantic competitor) generated interference. However, no such mediated priming was found in a parallel experiment with Chinese materials and Mandarin speakers (Experiment 2). These results suggest potential fundamental differences across the target languages in how activation is transmitted during lexical access.

Vitamin B Mediated Priming of Disease Resistance and Defense Responses to Tobacco Mosaic Virus in Capsicum annuum L. Plants

Thiamin (B1) and riboflavin (B2) can act as activators and priming factors of defense mechanisms for Tobacco Mosaic Virus (TMV) infection in Capsicum annuum plants. Effect of exogenous application of each vitamin on C. annuum leaves was demonstrated to induce defense responses and systemic resistance against TMV in the untreated parts of the plant. A range of concentrations was used of both vitamins. 70% of inhibition of TMV for thiamin and 64.1% for riboflavin were achieved, when applied just before virus inoculation. The induction of disease resistance and reduction of virus infectivity in C. annuum leaves were determined by indirect ELISA and local lesion host plant assay. The synergetic effect of both vitamins on TMV disease reduction was studied. To investigate the defensive enzymes responsible for the induction of resistance, the levels of Phenylalanine ammonia-lyase (PAL), Polyphenol Oxidase (PPO), and Peroxidase (POD) were examined by specific enzyme assay for each one, and the accumulation of the enzymes was detected 0 to 20 days after treating with the vitamins. Also, the up-regulation and expression of the defense genes POD, PPO, PAL, and some of the pathogenesis related proteins, PR4, PR9, and PR10 were studied by reverse transcriptase polymerase chain reaction (RT-PCR). Application of vitamins B1, and B2 significantly increased the activities of some of the pathogenesis related enzymes, and genes. The possible correlation between timing of application of elicitors and expression of defensive genes was also studied.

Prospective and retrospective processing in associative mediated priming

Mediated priming refers to the faster word recognition of a target (e.g., milk) following presentation of a prime (e.g., pasture) that is related indirectly via a connecting “mediator” (e.g., cow). Association strength may be an important factor in whether mediated priming occurs prospectively (with target activation prior to its presentation) or retrospectively. Mediated priming effects were compared for items having a strong (e.g., iceberg – cold –hot) versus weak (e.g., camel – desert –hot) mediator–target association. Priming obtained for both strong and weak mediator–target association conditions in lexical decision tasks (LDTs) conducive to retrospective processing, but only for the stronger items in more automatic LDTs. Results extend recent findings of mediated priming via retrospective processing (e.g., Jones, 2010), and further suggest that a strong mediator–target association is necessary in order for mediated priming to occur prospectively by spreading activation.

Face (and nose) priming for book: the malleability of semantic memory.

There are two general classes of models of semantic structure that support semantic priming effects. Feature-overlap models of semantic priming assume that shared features between primes and targets are critical (e.g., cat-DOG). Associative accounts assume that contextual co-occurrence is critical and that the system is organized along associations independent of featural overlap (e.g., leash-DOG). If unrelated concepts can become related as a result of contextual co-occurrence, this would be more supportive of associative accounts and provide insight into the nature of the network underlying "semantic" priming effects. Naturally co-occurring recent associations (e.g., face-BOOK) were tested under conditions that minimize strategic influences (i.e., short stimulus onset asynchrony and low relatedness proportion) in a semantic priming paradigm. Priming for new associations did not differ from the priming found for pre-existing relations (e.g., library-BOOK). Mediated priming (e.g., nose-BOOK) was also found. These results suggest that contextual associations can result in the reorganization of the network that subserves "semantic" priming effects.

Semantic Hyperpriming in Normal Aging: A Consequence of Instructions?

Semantic hyperpriming has consistently been found in normal aging. However, because the standard instructions to test semantic priming are generally ambiguous (focusing on both accuracy and speed), it is difficult to account for hyperpriming in older adults. By using the direct and mediated priming paradigms, this study investigates whether older adults' response mode at testing may explain hyperpriming. First, we show that, under identical conditions, inducing a response mode that favors speed leads to greater priming effects in older adults. The pattern of results is similar to what is observed under standard instructions. Second, prompting a response mode that favors accuracy leads to greater priming effects in younger adults. We discuss various explanations for these findings and conclude, in accordance with the Ratcliff, Thapar, Gomez, and McKoon (2004a) diffusion model, that hyperpriming in normal aging is contingent on older adults' response mode at testing.

Pure mediated priming: A retrospective semantic matching model.

Mediated priming refers to the activation of a target (e.g., stripes) by a prime (e.g., lion) that is related indirectly via a connecting mediator (e.g., tiger). In previous mediated priming studies (e.g., McNamara & Altarriba, 1988), the mediator was associatively related to the prime. In contrast, pure mediated priming (e.g., spoon --> can) lacks a strong association between prime and mediator (e.g., spoon --> soup) and between mediator and target (e.g., soup --> can). This study establishes the existence of pure mediated priming and assesses which semantic priming model (spreading activation, compound-cue, or semantic matching) accounts for the results. Pure mediated priming occurred in 3 experiments across double and standard lexical decision tasks. However, such priming did not occur in a continuous lexical decision task, which precludes strategic processing. Overall, results indicate that a modified retrospective semantic matching model provides the best theoretical explanation of pure mediated priming. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

Phonologically mediated priming of preexisting and new associations in young and older adults.

In 2 experiments, the authors investigated phonologically mediated priming of preexisting and new associations in word retrieval. Young and older adults completed paired word stems with the first word that came to mind. Priming of preexisting associations occurred when word-stem pairs containing homophones (e.g., beech-s____) showed more completions with the target (e.g., sand) relative to unrelated pairs (e.g., batch-s____), with more priming for subordinate than for dominant homophones. Priming occurred for new associations independent of dominance such that word-stem pairs containing homophones (e.g., beech-l____ and beach-l____) were completed with the same word (e.g., laugh) more often than unrelated pairs (e.g., beech-l____ and batch-l____). No age differences in phonologically mediated priming were found for either type of association, suggesting age equivalence in the use of bottom-up phonological connections.

Mediated priming in the cerebral hemispheres

The present experiment investigates hemispheric differences in mediated priming. Theories of lexical representation have argued for an asymmetrical coding between the right and left hemispheres ( Beeman, 1998), claiming that the right hemisphere is more diffusely represented compared to the left hemisphere. Thus, the right hemisphere activates a larger semantic field compared to the left hemisphere. Mediated (two-step) priming is an ideal task to examine this representational claim, because of the distant nature of the prime-target pairs. Results showed no difference in the magnitude of priming (both mediated and direct) between the right and left hemispheres. These results suggest that the lexical representation of the two hemispheres is equivalent, not asymmetrical as Beeman suggests.

Shock-Induced Neutrophil Mediated Priming for Acute Lung Injury in Mice: Divergent Effects of TLR-4 and TLR-4/FasL Deficiency

Acute lung injury (ALI) leading to respiratory distress is a common sequela of shock/trauma, however, modeling this process in mice with a single shock or septic event is inconsistent. One explanation is that hemorrhage is often just a "priming insult," thus, secondary stimuli may be required to "trigger" ALI. To test this we carried out studies in which we assessed the capacity of hemorrhage alone or hemorrhage followed by septic challenge (CLP) to induce ALI. Lung edema, bronchoalveolar lavage interleukin (IL)-6, alveolar congestion, as well as lung IL-6, macrophage inflammatory protein (MIP)-2, and myeloperoxidase (MPO) activity were all increased in mice subjected to CLP at 24 but not 72 hours following hemorrhage. This was associated with a marked increase in the susceptibility of these mice to septic mortality. Peripheral blood neutrophils derived from 24 hours post-hemorrhage, but not Sham animals, exhibited an ex vivo decrease in apoptotic frequency and an increase in respiratory burst capacity, consistent with in vivo "priming." Subsequently, we observed that adoptive transfer of neutrophils from hemorrhaged but not sham-hemorrhage animals to neutropenic recipients reproduce ALI when subsequently septically challenged, implying that this priming was mediated by neutrophils. We also found marked general increases in lung IL-6, MIP-2, and MPO in mice deficient for toll-like receptor (TLR-4) or the combined lack of TLR-4/FasL. However, the TLR-4 defect markedly attenuated neutrophil influx into the lung while not altering the change in local cytokine/chemokine expression. Alternatively, the combined loss of FasL and TLR-4 did not inhibit the increase in MPO and exacerbated lung IL-6/MIP-2 levels even further.

Information flow in the mental lexicon during speech planning: evidence from event-related brain potentials

A major issue in speech production research is the question of how speakers retrieve words from the so-called mental lexicon. Current models of lexical retrieval converge on the assumption that category associates of a target word are semantically activated during speech planning. However, the question of whether these competitors are also phonologically activated is less agreed on. Past research has addressed this issue by testing whether lexical retrieval of a picture name (e.g. sheep) affects, or is affected by, the processing of a word that is phonologically related to a semantic category associate to the picture name (e.g. goal, phonologically related to goat). Behavioral studies have failed to obtain such so-called mediated priming effects, but have been questioned on the grounds of possibly insufficient task sensitivity. As such priming effects have reliably been obtained with event-related brain potentials in word recognition, we used this approach for testing these effects in lexical retrieval during speech planning. Our results consistently demonstrate the absence of mediated priming effects, putting strong constraints on the activation flow in the mental lexicon during speech planning.

Associative priming in a masked perceptual identification task: evidence for automatic processes.

Two experiments investigated the influence of automatic and strategic processes on associative priming effects in a perceptual identification task in which prime-target pairs are briefly presented and masked. In this paradigm, priming is defined as a higher percentage of correctly identified targets for related pairs than for unrelated pairs. In Experiment 1, priming was obtained for mediated word pairs. This mediated priming effect was affected neither by the presence of direct associations nor by the presentation time of the primes, indicating that automatic priming effects play a role in perceptual identification. Experiment 2 showed that the priming effect was not affected by the proportion (.90 vs. .10) of related pairs if primes were presented briefly to prevent their identification. However, a large proportion effect was found when primes were presented for 1000 ms so that they were clearly visible. These results indicate that priming in a masked perceptual identification task is the result of automatic processes and is not affected by strategies. The present paradigm provides a valuable alternative to more commonly used tasks such as lexical decision.

Mediated Priming in the Lexical Decision Task: Evidence from Event-Related Potentials and Reaction Time

Mediated priming (e.g., from LION to STRIPES via TIGER) is predicted by spreading activation models but only by some integration models. The goal of the present research was to localize mediated priming by assessing two-step priming effects on N400 and reaction times (RT). We propose that the N400 priming effect mainly reflects integration processes but, in contrast with RT, does not reflect spreading activation. The results show that RT and N400 effects can dissociate. In a standard lexical decision task, we found mediated priming for N400 but not for RT. When a lexical decision to both the prime and the target was required, mediated priming was observed for both measures, but the RT effect was not influenced by list composition, whereas the N400 effect was. We conclude that two qualitatively different processes underlie the two types of mediated priming. A process of “global integration” yields an N400 effect, whereas an RT effect is evoked by spreading activation.

Phonology, Orthography, and Semantic Activation in Reading Chinese

Phonological and orthographic constraints on semantic activation in reading Chinese were investigated using a phonologically mediated semantic priming technique. In Experiment 1, we observed no significant mediated priming and homophone density effects for homophone mediated primes having no orthographic similarity with semantic primes. Such primes, when they contained regular phonetic radicals, did produce significant effects in Experiment 2. In Experiment 3, targets were facilitated to the same extent by mediated primes that were either orthographically similar and homophonic to or only orthographically similar to semantic primes. In Experiment 4, facilitatory effects equivalent to semantic priming were observed for orthographically similar homophone mediated primes containing regular and consistent phonetic radicals. We argue that access to semantics in reading Chinese is constrained by both phonology and orthography operating in interaction with each other, and that phonology has no inherently privileged role over orthography in constraining semantic activation.

Mediated Priming in Younger and Older Adults

This paper reports the result of a lexical decision experiment in which the primes were either directly related to their targets , mediated , or unrelated . Mediated primes are indirectly related to their targets through a single connecting link ( e . g ., PASTURE - COW - MILK ). Older and younger adult subjects responded to each letter string in a continuous lexical decision task , deciding whether each string was a word or a nonword . The results indicated that both younger and older subjects benefited from the mediated primes , as well as from the directly related primes . The results are discussed in relation to issues of age changes in processing speed .

Phonological, Semantic, and Mediated Priming in Aphasia

An auditory lexical decision task was conducted to examine rhyme, semantic, and mediated priming in nonfluent and fluent aphasic patients and normal controls. Overall, monosyllabic word targets were responded to faster when preceded by rhyming word and nonword primes than unrelated primes. Similarly, semantically related primes facilitated lexical decisions to word targets. No evidence of mediated priming emerged. Results for individual subjects suggest differences in patterns across the subject groups. Implications of the findings for the integrity of lexical access in aphasic patients are considered.

The regulation of neutrophil phospholipase A2 by granulocyte-macrophage colony-stimulating factor and its role in priming superoxide production.

Experiments were performed to investigate the relative role of phospholipase A2 (PLA2) in the activation and cytokine-mediated priming of neutrophil superoxide production. PLA2 activity was measured with a radiometric assay which discriminates between PLA2 and the downstream enzyme, 5-lipoxygenase. In cells that had not been primed by prior incubation with granulocyte-macrophage colony stimulating factor (GM-CSF), PLA2 and NADPH oxidase were differentially stimulated by the chemotactic peptide N-formyl-met-leu-phe (FMLP), calcium ionophore, or phorbol ester. In addition, inhibition of PLA2 by mepacrine (0-100 micromol/l) did not concomitantly inhibit FMLP-stimulated superoxide production. These findings suggest that the activity of PLA2 and NADPH oxidase may be uncoupled in the unprimed cell. In cells preincubated with GM-CSF, time- and dose-dependent priming of FMLP-stimulated PLA2 responses were observed and inhibition of PLA2 by mepacrine was accompanied by the inhibition of FMLP-stimulated superoxide production down to the level of unprimed cells. The effect of mepacrine was not due to inhibition of FMLP receptor expression. These data suggest that a mepacrine-sensitive PLA2 may have a role in the GM-CSF mediated priming of superoxide production. Using ionophore-stimulated PLA2 activity as a model, we showed that Bordatella pertussis toxin did not inhibit GM-CSF mediated priming, demonstrating that a pertussis-sensitive GTP-binding protein does not mediate signal transduction from the GM-CSF receptor to PLA2. The tyrosin kinase inhibitor, genestein, selectively inhibited GM-CSF primed but not unprimed PLA2 activity, demonstrating that GM-CSF-mediated priming requires tyrosine kinase activity.