Stress Cues Research Articles

Herbicide-related signaling in plants reveals novel insights for herbicide use strategies, environmental risk assessment and global change assessment challenges

Herbicide impact is usually assessed as the result of a unilinear mode of action on a specific biochemical target with a typical dose-response dynamics. Recent developments in plant molecular signaling and crosstalk between nutritional, hormonal and environmental stress cues are however revealing a more complex picture of inclusive toxicity. Herbicides induce large-scale metabolic and gene-expression effects that go far beyond the expected consequences of unilinear herbicide-target-damage mechanisms. Moreover, groundbreaking studies have revealed that herbicide action and responses strongly interact with hormone signaling pathways, with numerous regulatory protein-kinases and -phosphatases, with metabolic and circadian clock regulators and with oxidative stress signaling pathways. These interactions are likely to result in mechanisms of adjustment that can determine the level of sensitivity or tolerance to a given herbicide or to a mixture of herbicides depending on the environmental and developmental status of the plant. Such regulations can be described as rheostatic and their importance is discussed in relation with herbicide use strategies, environmental risk assessment and global change assessment challenges.

New Directions in Medication-Facilitated Behavioral Treatment for Substance Use Disorders.

A promising approach to addressing substance use disorders is to integrate pharmacotherapy with a behavioral treatment with which synergy is possible. In this review, we focus on recent research suggesting that this approach may be effective for cocaine and cannabis use disorders, both of which currently lack efficacious medications. We summarize potential targets of pharmacotherapy of particular relevance to combined medication-behavioral treatment and examine preliminary evidence of clinical efficacy. Common to these promising medications is a hypothesized mechanism of action predicated on reversing drug-related neural adaptations, such as high reactivity to stress or drug cues, that might undermine fruitful engagement with behavioral treatment. We also review emerging medications, such as certain glutamatergic and serotonergic agents, which may be feasibly integrated with existing treatments. We conclude with an outline of future directions for research.

UV-C-Induced alleviation of transcriptional gene silencing through plant–plant communication: Key roles of jasmonic acid and salicylic acid pathways

Plant stress responses at the epigenetic level are expected to allow more permanent changes of gene expression and potentially long-term adaptation. While it has been reported that plants subjected to adverse environments initiate various stress responses in their neighboring plants, little is known regarding epigenetic responses to external stresses mediated by plant–plant communication. In this study, we show that DNA repetitive elements of Arabidopsis thaliana, whose expression is inhibited epigenetically by transcriptional gene silencing (TGS) mechanism, are activated by UV-C irradiation through airborne plant–plant and plant–plant–plant communications, accompanied by DNA demethylation at CHH sites. Moreover, the TGS is alleviated by direct treatments with exogenous methyl jasmonate (MeJA) and methyl salicylate (MeSA). Further, the plant–plant and plant–plant–plant communications are blocked by mutations in the biosynthesis or signaling of jasmonic acid (JA) or salicylic acid (SA), indicating that JA and SA pathways are involved in the interplant communication for epigenetic responses. For the plant–plant–plant communication, stress cues are relayed to the last set of receiver plants by promoting the production of JA and SA signals in relaying plants, which exhibit upregulated expression of genes for JA and SA biosynthesis and enhanced emanation of MeJA and MeSA.

Acoustic analysis of Punjabi stress and tone (Doabi dialect)

An acoustic experiment was conducted to study the stress and tone systems of Punjabi, an under-documented Indo-Aryan language. Tone and stress are linked because tone associates with the stressed syllable (Bailey, 1914; Wells and Roach, 1980; Baart, 2003). The experiment was used determine the acoustic cues of stress and the tonal contours of the three Punjabi tones: default, rising, and falling. Five native speakers read a list of 85 words five times. Measurements of duration, intensity, f0 were made in Praatand analyzed in SPSS. The Mixed Models analysis of normalized intensity and duration revealed that the acoustic cue of stress is the duration of the rhyme. A similar finding for Hindi, a closely related language, is reported in Nair et al. (2001). As for tone, the default tone has the smallest f0 range and the falling tone has the largest f0 range. Falling tone is realized entirely on the stressed syllable whereas for the rising tone, the phenomenon of peak delay is observed unless tone occurs on a w...

Preference for Safe Over Risky Options in Binge Eating.

Binge eating has been usually viewed as a loss of control and an impulsive behavior. But, little is known about the actual behavior of binging patients (prevalently women) in terms of basic decision-making under risk or under uncertainty. In healthy women, stressful cues bias behavior for safer options, raising the question of whether food cues that are perceived as threatening by binging patients may modulate patients’ behaviors towards safer options. A cross-sectional study was conducted with binging patients (20 bulimia nervosa (BN) and 23 anorexia nervosa binging (ANB) patients) and two control groups (22 non-binging restrictive (ANR) anorexia nervosa patients and 20 healthy participants), without any concomitant impulsive disorder. We assessed decisions under risk with a gambling task with known probabilities and decisions under uncertainty with the balloon analog risk taking task (BART) with unknown probabilities of winning, in three cued-conditions including neutral, binge food and stressful cues. In the gambling task, binging and ANR patients adopted similar safer attitudes and coherently elicited a higher aversion to losses when primed by food as compared to neutral cues. This held true for BN and ANR patients in the BART. After controlling for anxiety level, these safer attitudes in the food condition were similar to the ones under stress. In the BART, ANB patients exhibited a higher variability in their choices in the food compared to neutral condition. This higher variability was associated with higher difficulties to discard irrelevant information. All these results suggest that decision-making under risk and under uncertainty is not fundamentally altered in all these patients.

Functional Connectivity During Exposure to Favorite-Food, Stress, and Neutral-Relaxing Imagery Differs Between Smokers and Nonsmokers.

Tobacco-use disorder is a complex condition involving multiple brain networks and presenting with multiple behavioral correlates including changes in diet and stress. In a previous functional magnetic resonance imaging (fMRI) study of neural responses to favorite-food, stress, and neutral-relaxing imagery, smokers versus nonsmokers demonstrated blunted corticostriatal-limbic responses to favorite-food cues. Based on other recent reports of alterations in functional brain networks in smokers, the current study examined functional connectivity during exposure to favorite-food, stress, and neutral-relaxing imagery in smokers and nonsmokers, using the same dataset. The intrinsic connectivity distribution was measured to identify brain regions that differed in degree of functional connectivity between groups during each imagery condition. Resulting clusters were evaluated for seed-to-voxel connectivity to identify the specific connections that differed between groups during each imagery condition. During exposure to favorite-food imagery, smokers versus nonsmokers showed lower connectivity in the supramarginal gyrus, and differences in connectivity between the supramarginal gyrus and the corticostriatal-limbic system. During exposure to neutral-relaxing imagery, smokers versus nonsmokers showed greater connectivity in the precuneus, and greater connectivity between the precuneus and the posterior insula and rolandic operculum. During exposure to stress imagery, smokers versus nonsmokers showed lower connectivity in the cerebellum. These findings provide data-driven insights into smoking-related alterations in brain functional connectivity patterns related to appetitive, relaxing, and stressful states. This study uses a data-driven approach to demonstrate that smokers and nonsmokers show differential patterns of functional connectivity during guided imagery related to personalized favorite-food, stress, and neutral-relaxing cues, in brain regions implicated in attention, reward-related, emotional, and motivational processes. For smokers, these differences in connectivity may impact appetite, stress, and relaxation, and may interfere with smoking cessation.

Effects of yohimbine and drug cues on impulsivity and attention in cocaine-dependent men and women and sex-matched controls

BackgroundDeficits in executive function have been associated with risk for relapse. Data from previous studies suggest that relapse may be triggered by stress and drug-paired cues and that there are significant sex differences in the magnitude of these responses. The aim of this study was to examine the impact of the pharmacological stressor and alpha-2 adrenergic receptor antagonist yohimbine and cocaine cues on executive function in cocaine-dependent men and women. MethodsIn a double-blind placebo controlled cross-over study, cocaine-dependent men (n=12), cocaine-dependent women (n=27), control men (n=31) and control women (n=25) received either yohimbine or placebo prior to two cocaine cue exposure sessions. Participants performed the Connors’ Continuous Performance Test II prior to medication/placebo administration and immediately after each cue exposure session ResultsHealthy controls had a significant increase in commission errors under the yohimbine condition [RR (95% CI)=1.1 (1.0–1.3), χ21=2.0, p=0.050]. Cocaine-dependent individuals exhibited a significant decrease in omission errors under the yohimbine condition [RR (95% CI)=0.6 (0.4–0.8), χ21=8.6, p=0.003]. Cocaine-dependent women had more omission errors as compared to cocaine-dependent men regardless of treatment [RR (95% CI)=7.2 (3.6–14.7), χ21=30.1, p<0.001]. Cocaine-dependent women exhibited a slower hit reaction time as compared to cocaine-dependent men [Female 354±13 vs. Male 415±14; t89=2.6, p=0.012]. ConclusionsThese data add to a growing literature demonstrating significant sex differences in behaviors associated with relapse in cocaine-dependent individuals.

Subcellular localization of five singular WSC domain-containing proteins and their roles in Beauveria bassiana responses to stress cues and metal ions.

Some model fungi have three or four proteins with each vectoring a single cell Wall Stress-responsive Component (WSC) domain at N-terminus. In this study, five proteins, each vectoring only a single WSC domain in N-terminal, central or even C-terminal region, were found in Beauveria bassiana, a filamentous fungal entomopathogen, and named Wsc1A-1E due to the domain singularity. Four of them lack either transmembrane domain or C-terminal conserved signature sequence (DXXD) compared with the homologues in the model fungi. Intriguingly, all the eGFP-tagged fusion proteins of Wsc1A-1E were evidently localized to the cell wall and membrane of transgenic hyphae. Single deletions of the five wsc genes resulted in significant, but differential, increases in cellular sensitivity to cell wall perturbation, oxidation, high osmolarity, and four to six metal ions (Zn(2+) , Mg(2+) , Fe(2+) , K(+) , Ca(2+) and Mn(2+) ). Each deletion mutant also showed a delay of germination and a decrease of conidial UV-B resistance, thermotolerance or both. However, none of the deletions affected substantially the fungal growth, conidiation and virulence. Our results indicate a significance of each WSC protein for the B. bassiana adaptation to diverse habitats of host insects.

WrpA Is an Atypical Flavodoxin Family Protein under Regulatory Control of the Brucella abortus General Stress Response System

The general stress response (GSR) system of the intracellular pathogen Brucella abortus controls the transcription of approximately 100 genes in response to a range of stress cues. The core genetic regulatory components of the GSR are required for B. abortus survival under nonoptimal growth conditions in vitro and for maintenance of chronic infection in an in vivo mouse model. The functions of the majority of the genes in the GSR transcriptional regulon remain undefined. bab1_1070 is among the most highly regulated genes in this regulon: its transcription is activated 20- to 30-fold by the GSR system under oxidative conditions in vitro. We have solved crystal structures of Bab1_1070 and demonstrate that it forms a homotetrameric complex that resembles those of WrbA-type NADH:quinone oxidoreductases, which are members of the flavodoxin protein family. However, B. abortus WrbA-related protein (WrpA) does not bind flavin cofactors with a high affinity and does not function as an NADH:quinone oxidoreductase in vitro. Soaking crystals with flavin mononucleotide (FMN) revealed a likely low-affinity binding site adjacent to the canonical WrbA flavin binding site. Deletion of wrpA (ΔwrpA) does not compromise cell survival under acute oxidative stress in vitro or attenuate infection in cell-based or mouse models. However, a ΔwrpA strain does elicit increased splenomegaly in a mouse model, suggesting that WrpA modulates B. abortus interaction with its mammalian host. Despite high structural homology with canonical WrbA proteins, we propose that B. abortus WrpA represents a functionally distinct member of the diverse flavodoxin family. Brucella abortus is an etiological agent of brucellosis, which is among the most common zoonotic diseases worldwide. The general stress response (GSR) regulatory system of B. abortus controls the transcription of approximately 100 genes and is required for maintenance of chronic infection in a murine model; the majority of GSR-regulated genes remain uncharacterized. We present in vitro and in vivo functional and structural analyses of WrpA, whose expression is strongly induced by GSR under oxidative conditions. Though WrpA is structurally related to NADH:quinone oxidoreductases, it does not bind redox cofactors in solution, nor does it exhibit oxidoreductase activity in vitro. However, WrpA does affect spleen inflammation in a murine infection model. Our data provide evidence that WrpA forms a new functional class of WrbA/flavodoxin family proteins.

Regulation of WRKY46 Transcription Factor Function by Mitogen-Activated Protein Kinases in Arabidopsis thaliana.

Mitogen-activated protein kinase (MAPK) cascades are central signaling pathways activated in plants after sensing internal developmental and external stress cues. Knowledge about the downstream substrate proteins of MAPKs is still limited in plants. We screened Arabidopsis WRKY transcription factors as potential targets downstream of MAPKs, and concentrated on characterizing WRKY46 as a substrate of the MAPK, MPK3. Mass spectrometry revealed in vitro phosphorylation of WRKY46 at amino acid position S168 by MPK3. However, mutagenesis studies showed that a second phosphosite, S250, can also be phosphorylated. Elicitation with pathogen-associated molecular patterns (PAMPs), such as the bacterial flagellin-derived flg22 peptide led to in vivo destabilization of WRKY46 in Arabidopsis protoplasts. Mutation of either phosphorylation site reduced the PAMP-induced degradation of WRKY46. Furthermore, the protein for the double phosphosite mutant is expressed at higher levels compared to wild-type proteins or single phosphosite mutants. In line with its nuclear localization and predicted function as a transcriptional activator, overexpression of WRKY46 in protoplasts raised basal plant defense as reflected by the increase in promoter activity of the PAMP-responsive gene, NHL10, in a MAPK-dependent manner. Thus, MAPK-mediated regulation of WRKY46 is a mechanism to control plant defense.

Signal integration by Ca2+ regulates intestinal stem-cell activity

SummarySomatic stem cells (SCs) maintain tissue homeostasis by dynamically adjusting proliferation and differentiation in response to stress and metabolic cues. Here, we identify Ca2+ signaling as a central regulator of intestinal SC (ISC) activity in Drosophila. We find that dietary L-glutamate stimulates ISC division and gut growth. The metabotropic glutamate receptor (mGluR) is required in ISCs for this response and for an associated modulation of cytosolic Ca2+ oscillations that results in sustained high cytosolic Ca2+ concentrations. High cytosolic Ca2+ induces ISC proliferation by regulating Calcineurin and CREB - regulated transcriptional co-activator (CRTC). In response to a wide range of dietary and stress stimuli, ISCs reversibly transition between Ca2+ oscillation states that represent poised or activated modes of proliferation, respectively. We propose that the dynamic regulation of intracellular Ca2+ levels allows effective integration of diverse mitogenic signals in ISCs to tailor their proliferative activity to the needs of the tissue.

Peripheral and prefrontal stress system markers and risk of relapse in alcoholism.

Previous research has shown that hyperactivation in ventral medial prefrontal cortex (VmPFC) and rostral anterior cingulate cortex (rACC) and high cortisol to corticotrophin ratio (cort:ACTH ratio) during neutral-relaxed states predict relapse in alcohol-dependent (AD) patients. Other studies have shown that VmPFC/rACC deactivation and blunted cortisol release to stress and alcohol cues are predictive of time to relapse and relapse severity. However, no previous study has assessed the relationship between these markers of central and peripheral nervous system dysfunction in AD participants and their potential joint effects on relapse risk. Forty early abstinent, treatment engaged AD patients underwent a laboratory experiment with exposure to neutral, alcohol and stress cues and a separate functional magnetic resonance imaging scan with similar cue exposure. Neutral-relaxed state cort:ACTH ratio was significantly associated with VmPFC hyperreactivity to neutral-relaxing cues, and also with hypoactivation in response to alcohol and stress cues in AD patients. Basal heart rate, neutral cort:ACTH ratio and neutral VmPFC hyperreactivty were each associated with risk of relapse. However, abnormal VmPFC activation and elevated cort:ACTH ratio overlap in predicting risk for relapse, and dysfunctional VmPFC response was the sole significant predictor of odds of relapse in a joint model of relapse risk. These findings suggest that the cort:ACTH ratio may serve as a peripheral marker of VmPFC brain dysfunction, while aberrant VmPFC responses need further evaluation as a potential biomarker of alcohol relapse risk in clinical outcome studies.

Perception of Sentence Stress in Speech Correlates With the Temporal Unpredictability of Prosodic Features.

Numerous studies have examined the acoustic correlates of sentential stress and its underlying linguistic functionality. However, the mechanism that connects stress cues to the listener's attentional processing has remained unclear. Also, the learnability versus innateness of stress perception has not been widely discussed. In this work, we introduce a novel perspective to the study of sentential stress and put forward the hypothesis that perceived sentence stress in speech is related to the unpredictability of prosodic features, thereby capturing the attention of the listener. As predictability is based on the statistical structure of the speech input, the hypothesis also suggests that stress perception is a result of general statistical learning mechanisms. To study this idea, computational simulations are performed where temporal prosodic trajectories are modeled with an n-gram model. Probabilities of the feature trajectories are subsequently evaluated on a set of novel utterances and compared to human perception of stress. The results show that the low-probability regions of F0 and energy trajectories are strongly correlated with stress perception, giving support to the idea that attention and unpredictability of sensory stimulus are mutually connected.

Laboratory-induced stress and craving among individuals with prescription opioid dependence

BackgroundStress and conditioned drug cues have been implicated in the initiation, maintenance and relapse to substances of abuse. Although stress and drug cues are often encountered together, little research exists on whether stress potentiates the response to drug cues. MethodParticipants (N=75) were 39 community recruited individuals with current prescription opioid (PO) dependence and 36 healthy controls. Participants stayed overnight in the hospital for one night and then completed laboratory testing the following morning. During laboratory testing, participants were randomly assigned to a stress task (Trier Social Stress Task; TSST) or a no-stress condition. Following the stress manipulation, all participants completed a PO cue paradigm. Immediately before and after the stress and cue tasks, the following were assessed: subjective (stress, craving, anger, sadness, happiness), physiological (heart rate, blood pressure, galvanic skin response), and neuroendocrine responses (cortisol and dehydroepiandrosterone). ResultsInternal validity of the stress task was demonstrated, as evidenced by significantly higher subjective stress, as well as cortisol, heart rate and blood pressure in the TSST compared to the no-stress group. Individuals with PO dependence evidenced significantly greater reactivity to the stress task than controls. Craving increased significantly in response to the drug cue task among PO participants. No stress×cue interaction was observed. ConclusionsIn this study, heightened stress reactivity was observed among individuals with PO dependence. Exposure to acute stress, however, did not potentiate craving in response to conditioned drug cues.

Phonetic Training Significantly Mitigates the Stress ‘Deafness’ of French Speakers

&lt;p&gt;Stress ‘deafness’ refers to the inconsistent perception and/or processing of phonological stress by speakers of fixed stress languages such as French. This paper briefly reports on the results of a study in which French and English participants performed an ABX word stress task, similar to Dupoux et al.’s (1997) Experiment 1. One group of French and a group of English speakers received phonetic training designed to improve perception while two other groups of French and English speakers received no training. The training was an adaptation of the perceptual fading technique, which exposes listeners to stressed syllables that exaggerate the durational correlate of stress, then gradually reduces the durations of subsequent stressed syllables to increase participants’ overall ability to accurately perceive stressed syllables. The trained French group performed significantly better than the untrained group with fewer errors and lower response times. As expected there was no difference in accuracy between the trained and untrained English groups. We argue that by exaggerating the duration cue for stress, the phonetic training led to increased overall perception, perhaps even beginning to build an abstract phonological representation of stress that was then carried into the ABX task. Although trained on artificially manipulated stimuli, participants were able to perform well on naturally-produced novel stimuli.&lt;/p&gt;

Stress, cues, and eating behavior. Using drug addiction paradigms to understand motivation for food

Eating patterns that lead to overconsumption of high fat, high sugar (HFHS) foods share similar features with addictive behaviors. Application of addiction paradigms, such as stress inductions, cue reactivity and behavioral economic assessments, to the study of motivation for HFHS food consumption may be a promising means of understanding food consumption. To date, few studies have investigated the interaction of stress and environmental cues on craving, and no study leveraged the state relative reinforcing value of foods (RRVfood) under varying conditions of affective states, the foci of the current study. This study used a mixed factorial design (Mood Induction: Neutral, Stress; Cues: Neutral, Food) with repeated measures on time (Baseline, Post-Mood Induction, Post-Cue Exposure). Participants (N = 133) were community adults who endorsed liking of HFHS snacks but denied eating pathology. The primary DVs were subjective craving and RRVfood. Negative and positive affect (NA, PA), the amount of food consumed, and latency to first bite were also examined. Participants in the Stress condition reported no change in craving or RRVfood. Exposure to food cues significantly increased participants' craving and RRVfood, but an interaction of stress and cues was not present. Participants did not differ on how many calories they consumed based on exposure to stress or food cues, but participants in the food cues condition had a shorter latency to the first bite of food. This study highlights the importance of environmental cues in food motivation. It also demonstrates the utility of using RRVfood to further characterize food motivation.

Food, stress, and circulating testosterone: Cue integration by the testes, not the brain, in male zebra finches (Taeniopygia guttata)

Food abundance is closely associated with reproductive readiness in vertebrates. Food scarcity can activate the hypothalamo–pituitary–adrenal axis, decrease sex steroid secretion, and dampen reproductive behavior. However, the mechanisms underlying these transient effects are unclear. Gonadotropin inhibitory hormone (GnIH), a neuropeptide present in the brain and gonads, is also influenced by glucocorticoids and fasting in some species. We investigated whether fasting stress activated the GnIH system in zebra finches (Taeniopygia guttata), with the potential for downstream effects on reproductive physiology and behavior. We fasted or fed males ad libitum for 10h. Fasting increased corticosterone and decreased testosterone in circulation. To assess whether the decrease in testosterone was mediated by changes in the hypothalamus and/or the gonads, we (1) quantified GnRH- and GnIH-positive neurons in the hypothalamus, (2) assessed hypothalamic gene expression for GnRH and GnIH, and (3) examined gene expression for proteins involved in testosterone synthesis in fasted and control birds. No measure of hypothalamic neuropeptides was related to treatment or circulating steroids. However, birds with higher corticosterone had higher testicular GnIH expression and lower testosterone. StAR and LHR expression were lower in the testes of fasted birds than controls. Thus, the decrease in testosterone was not likely mediated by hypothalamic GnIH, but rather by direct actions of fasting and/or corticosterone on the testes, indicating that the testes can integrate and respond to cues of stress directly. Such local inhibition of testosterone synthesis may allow for rapid and reversible changes in physiology and behavior when conditions are inappropriate for breeding.

The contribution of temporal modulations to speech intelligibility: Some thoughts about the speech envelope

Rosen [Phil. Trans. R. Soc. Lond. B 336, 367–373 (1992)] laid out an extremely useful framework for discussing temporal information in speech. Three broad categories were defined: temporal envelope (2–50 Hz), periodicity (50–500 Hz), and temporal fine-structure (600–10,000 Hz). The slower modulations associated with the speech envelope convey segmental cues for voicing and manner-of-articulation, and prosodic cues for syllabification and stress. These cues are manifest in the attack and fall times as well as the overall duration of the envelope segments. The mid-rate fluctuations associated with periodicity convey manner cues (periodic vs aperiodic) as well as voice pitch (an essential cue for intonation and stress). The faster rate modulations associated with temporal fine-structure (modulations within each pitch period) convey place-of-articulation cues and spectral-shape cues for manner-of-articulation and voicing. Studies that try to separate the effects of each of these temporal categories on speech perception often use signal processing strategies that filter out the temporal modulations of interest and present this information without periodicity or temporal fine-structure to listeners. The processing details of how the temporal envelope is extracted are critical to whether cues more readily associated with periodicity or fine-structure are inadvertently presented to listeners. Examples will be provided.

English listeners use suprasegmental lexical stress online during spoken word recognition

Lexical stress facilitates spoken word recognition. In English, listeners primarily rely on vowel reduction in unstressed syllables as a cue to lexical stress, but are nevertheless sensitive to suprasegmental cues (Cooper et al., 2002 Lang. Speech). In the present study, we tested with a visual-world eye-tracking paradigm whether English listeners utilize suprasegmental stress cues online during word recognition. On each trial, listeners heard one of four displayed printed words. Two of the words (critical words) were segmentally identical in their first two syllables but differed in the suprasegmental realization of stress in their first syllable. The first syllable had either primary (e.g., admiral) or secondary (admiration) lexical stress. The other two words were phonologically and semantically unrelated to the critical items. In the critical word trials, listeners looked more frequently at the targets with initial primary stress than at the competitors with secondary stress during the presentation of the first two syllables. No difference was found when the targets had secondary stress. The degree to which competitors were fixated was not modulated by stress. This suggests that English listeners use the presence, but not the absence, of suprasegmental cues to primary lexical stress during word recognition.

Metrical expectations from preceding prosody influence perception of lexical stress.

Two visual-world experiments tested the hypothesis that expectations based on preceding prosody influence the perception of suprasegmental cues to lexical stress. The results demonstrate that listeners' consideration of competing alternatives with different stress patterns (e.g., 'jury/gi'raffe) can be influenced by the fundamental frequency and syllable timing patterns across material preceding a target word. When preceding stressed syllables distal to the target word shared pitch and timing characteristics with the first syllable of the target word, pictures of alternatives with primary lexical stress on the first syllable (e.g., jury) initially attracted more looks than alternatives with unstressed initial syllables (e.g., giraffe). This effect was modulated when preceding unstressed syllables had pitch and timing characteristics similar to the initial syllable of the target word, with more looks to alternatives with unstressed initial syllables (e.g., giraffe) than to those with stressed initial syllables (e.g., jury). These findings suggest that expectations about the acoustic realization of upcoming speech include information about metrical organization and lexical stress and that these expectations constrain the initial interpretation of suprasegmental stress cues. These distal prosody effects implicate online probabilistic inferences about the sources of acoustic-phonetic variation during spoken-word recognition.