Contextual Stimuli Research Articles

Effects of Ultrasound Familiarization on Production and Perception of Nonnative Contrasts

Background/Aims: We investigated the efficacy of ultrasound imaging of the tongue as a tool for familiarizing naïve learners with the production of a class of nonnative speech sounds: palatalized Russian consonants. Methods: Two learner groups were familiarized, one with ultrasound and one with audio only. Learners performed pre- and postfamiliarization production and discrimination tasks. Results: Ratings of productions of word-final palatalized consonants by learners from both groups improved after familiarization, as did discrimination of the palatalization contrast word-finally. There were no significant differences in the improvement between groups in either task. All learners were able to generalize to novel contexts in production and discrimination. The presence of palatalization interfered with discrimination of word-initial manner, and ultrasound learners were more successful in overcoming that interference. Conclusion: Ultrasound familiarization resulted in improvements in production and discrimination comparable to audio only. Ultrasound familiarization additionally helped learners overcome difficulties in manner discrimination introduced by palatalization. When familiarizing learners with a novel, nonnative class of sounds, a small set of stimuli in different contexts may be more beneficial than using a larger set in one context. Although untrained production can disrupt discrimination training, we found that production familiarization was not disruptive to discrimination or production.

CINET: A Brain-Inspired Deep Learning Context-Integrating Neural Network Model for Resolving Ambiguous Stimuli.

The brain uses contextual information to uniquely resolve the interpretation of ambiguous stimuli. This paper introduces a deep learning neural network classification model that emulates this ability by integrating weighted bidirectional context into the classification process. The model, referred to as the CINET, is implemented using a convolution neural network (CNN), which is shown to be ideal for combining target and context stimuli and for extracting coupled target-context features. The CINET parameters can be manipulated to simulate congruent and incongruent context environments and to manipulate target-context stimuli relationships. The formulation of the CINET is quite general; consequently, it is not restricted to stimuli in any particular sensory modality nor to the dimensionality of the stimuli. A broad range of experiments is designed to demonstrate the effectiveness of the CINET in resolving ambiguous visual stimuli and in improving the classification of non-ambiguous visual stimuli in various contextual environments. The fact that the performance improves through the inclusion of context can be exploited to design robust brain-inspired machine learning algorithms. It is interesting to note that the CINET is a classification model that is inspired by a combination of brain’s ability to integrate contextual information and the CNN, which is inspired by the hierarchical processing of information in the visual cortex.

Interactions between Motivational and Discriminative Functions of Motivating Operations in the Renewal of Operant Responding in Mice

Renewal is a phenomenon in which a response that has been extinguished recovers when an organism is removed from the setting in which extinction occurred. In most renewal studies, context consists of exteroceptive stimuli (e.g., distinct visual, auditory, tactile, and/or olfactory stimuli). Nevertheless, a number of studies have shown that interoceptive stimuli such as those induced by drugs or food deprivation may come to exert discriminative control over behavior under the relevant contingencies. We investigated how interoceptive organismic conditions brought about through food deprivation and satiation motivating operations (MOs) can serve as contextual cues for the renewal of extinguished operant responding in mice. Three groups of mice received acquisition and extinction sessions under three different combinations of food deprivation and satiation. One group received acquisition sessions while deprived and extinction sessions while satiated. A second group received both acquisition and extinction sessions while satiated. A third group received both acquisition and extinction sessions while deprived. All groups were then tested for renewal under both deprivation and satiation conditions. ABA and AAB renewal were observed for the first two groups under deprivation conditions, but AAB renewal was not observed for the third group under satiation conditions. The results suggest that interoceptive stimuli elicited by MOs may serve as contextual stimuli that occasion the recovery of responding following extinction, but unlike exteroceptive contextual cues, the discriminative functions of these stimuli are accompanied by motivational functions that may affect the extent to which renewal is observed.

Environmental Attitudes and Contextual Stimuli in the Emerging Environmental Culture: An Empirical Study from Russia

The state of the environment inevitably depends on human activity and behavioral patterns that determine everyday decisions at the individual level. This impact turns out to be especially critical when the environmental culture is not formed and there are no positive social and context inducements. In this paper, based on a randomized experimental design, we investigate how some psychological factors such as attitudes and contextual stimuli influence the tendency towards greener behavior and the choice of eco-friendly everyday practices. We distinguish four types of everyday eco-friendly and pro-ecological behavior (recycling, eco-shopping, resource saving, eco-mobility) and analyze whether the choice in favor of a particular behavior is resistant to situational stimuli of an emotional and rational nature. Also, we clarify how the extent of pro-ecological activity is homogeneous at the individual level under conditions of the emerging environmental culture (using the example of Russia). By using data of an online survey of 330 respondents aged 14 to 67 from 81 Russian cities, we constructed an index of the tendency towards pro-ecological behavior and built models to test three main hypotheses about a society with an emerging environmental culture: H1. Eco-behavior is not homogeneous – a tendency towards one type of eco-behavior does not determine a tendency towards another; H2. People usually overestimate their own tendency towards eco-behavior and underestimate the tendency of others; H3. Tendency towards one or another type of eco-behavior is not persistent and influenced by emotional and rational stimuli.

Experiences of family members of children with cystic fibrosis under the light of Callista Roy.

To know the experiences of family members of children with cystic fibrosis under the light of the theory of Callista Roy. Qualitative research that used the adaptation theoretical framework of Callista Roy for inductive content analysis. Fifteen family members, in a university hospital, between 23 and 63 years old, participated in the study, from September to October 2018. Two categories were elaborated: "Evaluation of stimuli" and "Evaluation of behaviors". The first has three subcategories: "focal", "contextual" and "residual". And the second, four subcategories: "physiological domain", "self-concept", "role function" and "interdependence". During the evaluation of stimuli, work overload and stress were identified as focal stimuli. Regarding contextual stimuli, it was noticed that the social life of caregivers was prejudiced. As for residual stimuli, the fear of loss is constant, and it appears that the emotional aspect of family members is the most affected comparing with physical exhaustion.

Neural Representation of Loudness: Cortical Evoked Potentials in an Induced Loudness Reduction Experiment.

Loudness context effects comprise differences in judgments of the loudness of a target stimulus depending on the presence of a preceding inducer tone. Interstimulus intervals (ISIs) between inducer tone and target tone of about 200 ms and above cause an induced loudness reduction (ILR) of the target tone. As the ILR increases, respectively, the perceived loudness of the target stimuli decreases with increasing ISI. This in turn means that identical stimuli in a different context have a differently perceived loudness. A correlation between specific characteristics in the electroencephalography responses and perceived loudness in an ILR experiment would therefore provide a neurophysiological indication of loudness processing beyond a neural representation of stimulus intensity only. To examine if such a correlation exists, we investigated cortical electroencephalography responses in a latency range from 75 to 510 ms during a psychoacoustical ILR experiment with different ISIs. With increasing ISI, the strength of the N1-P2 deflection of the respective electroencephalography response decreases similarly to the loudness perception of the target tone pulse. This indicates a representation based on loudness rather than on intensity at the corresponding processing stage.

Skeletal muscle thermogenesis induction by exposure to predator odor.

Non-shivering thermogenesis can promote negative energy balance and weight loss. In this study, we identified a contextual stimulus that induces rapid and robust thermogenesis in skeletal muscle. Rats exposed to the odor of a natural predator (ferret) showed elevated skeletal muscle temperatures detectable as quickly as 2 min after exposure, reaching maximum thermogenesis of >1.5°C at 10-15 min. Mice exhibited a similar thermogenic response to the same odor. Ferret odor induced a significantly larger and qualitatively different response from that of novel or aversive odors, fox odor or moderate restraint stress. Exposure to predator odor increased energy expenditure, and both the thermogenic and energetic effects persisted when physical activity levels were controlled. Predator odor-induced muscle thermogenesis is subject to associative learning as exposure to a conditioned stimulus provoked a rise in muscle temperature in the absence of the odor. The ability of predator odor to induce thermogenesis is predominantly controlled by sympathetic nervous system activation of β-adrenergic receptors, as unilateral sympathetic lumbar denervation and a peripherally acting β-adrenergic antagonist significantly inhibited predator odor-induced muscle thermogenesis. The potential survival value of predator odor-induced changes in muscle physiology is reflected in an enhanced resistance to running fatigue. Lastly, predator odor-induced muscle thermogenesis imparts a meaningful impact on energy expenditure as daily predator odor exposure significantly enhanced weight loss with mild calorie restriction. This evidence signifies contextually provoked, centrally mediated muscle thermogenesis that meaningfully impacts energy balance.

Coronavirus pandemic in light of nursing theories.

to reflect on the interface between the Coronavirus pandemic and nursing theories. theoretical-reflective assay, anchored in the theoretical constructs of Dorothea Orem, Florence Nightingale and Callista Roy. in the interface with Orem, the professional, based on the nursing systems, offers health education for the virus prevention, the conduct of home isolation and in high complexity assistance when there is worsening of COVID19; with Nightingale, it is revealed the importance of environmental sanitation, ventilation, personal and domestic cleaning and the surrounding areas; with Roy, focal stimuli are perceived such as the symptoms of COVID19, contextual stimuli related to comorbidities, and residual stimuli, concerning to work stress due to high viral transmission and lack of protective equipment. nurses can use the theoretical framework of nursing theories as tools to guide their care in this pandemic situation.

Operant renewal of desirable behavior in a simulated workplace: A translational model.

Organizational settings are replete with changing stimulus contexts and contingencies, which makes relapse a particularly relevant framework for understanding the ways in which controlling stimuli influence employee responding. The purpose of the current study was to develop a translational model to assess renewal of desirable behavior in a simulated workplace with neurotypical adults. Experiment 1 assessed renewal of desirable behavior using a computerized check processing task. Experiment 2 extended the findings and the translational utility of the experimental arrangement to implementation of a behavior-analytic teaching procedure. Results across both experiments demonstrated renewal of desirable behavior. Overall, the current methodology and findings extend the human operant literature on renewal and demonstrate a translational model that brings together operant renewal and organizational behavior management.

CONTEXTUAL CONTROL OVER COMPOUND STIMULI: AN APPLICATION TO THE TEACHING OF NUMBERS

The purpose of this research was to teach the discrimination between “equal” and “different” for the quantities and written form of various numbers. In the procedure used, a contextual control for conditional discriminations that included compound stimuli was presented. A five year old girl learnt that the choice of one of four stimuli (number one, number two, quantity one, quantity two) depended on the presentation of a contextual stimulus (equal or different) and a conditional stimulus composed of two words (one-quantity, one-number, two-quantity, two-number). Once the eight possible combinations of stimuli were learnt, the contextual stimuli were presented for two new numbers. The results showed the transference of learning without deliberate teaching for two new numbers which included compound stimuli.

Activation of c-Fos Expression in the Retrosplenial Cortex but Not the Hippocampus Accompanies Formation of an Association between the Context and the Unconditioned Stimulus and Its Subsequent Retrieval in Mice

Identification of the neural mechanisms of associative memory is one of the fundamental tasks in neuroscience. We report here use of a model of associative learning in mice in which formation of a memory of a neutral context and subsequent association of transient presentation of this context with an unconditioned electrocutaneous stimulus (footshock) were separated in time. This provided for studies of relationship between different stages in the formation of this memory and protein synthesis and allowed us to study genomic activation of various brain structures during association and the memory of the context of the footshock. These studies showed that blockade of protein synthesis both during exploration of the novel context and during application of immediate footshock in an already familiar context impaired conditioned reflex freezing to this context. The association of the memory trace of the context of the footshock retrieved in response to a reminder was accompanied by activation of the expression of transcription factor c-Fos in the retrosplenial cortex. The retrosplenial cortex was also specifically activated by subsequent retrieval of the associative memory of the context. This activation was not seen in mice with impaired memory. No such differences were seen in the hippocampus, where activation of c-Fos expression occurred in relation to exploration of the novel context and not its association with the footshock. These results provide evidence that the retrosplenial cortex may be part of the neocortex supporting formation of associations between context and aversive unconditioned stimuli.

Neuromagnetic activation and oscillatory dynamics of stimulus-locked processing during naturalistic viewing

Naturalistic stimuli such as watching a movie while in the scanner provide an ecologically valid paradigm that has the potential of extracting valuable information on how the brain processes complex stimuli in realistic visual and auditory contexts. Naturalistic viewing is also easier to conduct with challenging participant groups including patients and children. Given the high temporal resolution of MEG, in the present study, we demonstrate how a short movie clip can be used to map distinguishable activation and connectivity dynamics underlying the processing of specific classes of visual stimuli such as face and hand manipulations, as well as contrasting activation dynamics for auditory words and non-words.MEG data were collected from 22 healthy volunteers (6 females, 3 left handed, mean age – 27.7 ​± ​5.28 years) during the presentation of naturalistic audiovisual stimuli. The MEG data were split into trials with the onset of the stimuli belonging to classes of interest (words, non-words, faces, hand manipulations). Based on the components of the averaged sensor ERFs time-locked to the visual and auditory stimulus onset, four and three time-windows, respectively, were defined to explore brain activation dynamics. Pseudo-Z, defined as the ratio of the source-projected time-locked power to the projected noise power for each vertex, was computed and used as a proxy of time-locked brain activation. Statistical testing using the mean-centered Partial Least Squares analysis indicated periods where a given visual or auditory stimuli had higher activation. Based on peak pseudo-Z differences between the visual conditions, time-frequency resolved analyses were performed to assess beta band desynchronization in motor-related areas, and inter-trial phase synchronization between face processing areas. Our results provide the first evidence that activation and connectivity dynamics in canonical brain regions associated with the processing of particular classes of visual and auditory stimuli can be reliably mapped using MEG during presentation of naturalistic stimuli. Given the strength of MEG for brain mapping in temporal and frequency domains, the use of naturalistic stimuli may open new techniques in analyzing brain dynamics during ecologically valid sensation and perception.

A review of investigations of operant renewal with human participants: Implications for theory and practice.

Operant renewal is the recurrence of a previously eliminated target behavior as a function of changing stimulus contexts. Renewal as a model of treatment relapse in humans suggests that a change in stimulus conditions or context is sufficient to produce relapse of a previously eliminated maladaptive behavior. The extent to which general findings from operant renewal studies involving nonhuman animal subjects are supported by relapse studies involving human participants is unknown. We conducted a systematic review of studies demonstrating or mitigating operant renewal in human participants in peer-reviewed studies found in PsycINFO, ERIC, PubMed, and Scopus between 1980 and 2019. We identified 12 studies involving 61 participants and 93 cases of operant renewal. We coded descriptive data on participant and study characteristics and calculated summary statistics. Results indicated that the renewal effect was a robust phenomenon, supported by demonstrations in both clinical and human-laboratory studies, and across a variety of variables and experimental preparations. However, there were relatively few studies involving human participants that attempted to reduce or eliminate renewal of clinically meaningful behavior. We discuss variables relevant for studying renewal in socially meaningful contexts, practical limitations of observing the renewal effect in real-world settings, implications for theoretical models of renewal, and identify barriers to methodology unique to human participants. We provide directions for future research related to implementing and translating nonhuman animal studies of renewal to applied settings.

Configural superiority for varying contrast levels.

Observers can search for a target stimulus at a particular speed and accuracy. Adding an identical context to each stimulus can improve performance when the resulting stimuli form clearly discriminable configurations. This search advantage is known as the configural superiority effect (CSE). A recent study showed that embedding these stimuli in noise revealed lower contrast thresholds for part-stimuli compared to configural stimuli (Bratch et al., Journal of Experimental Psychology. Human Perception and Performance, 42(9), 1388-1398, 2016). This contrasts with the accuracy advantages traditionally associated with CSEs. In this study, we aimed to replicate the results of Bratch et al. and asked whether the benefit for part-stimuli held across the full psychometric function. Additionally, we tested whether embedding the stimuli in noise was crucial for obtaining their result and whether different contrast definitions affected the results. Furthermore, we used control stimuli that were more directly comparable. Our results showed a detection benefit for the Gestalt context stimuli in all conditions. Together, these results are in line with the literature on CSEs and do not seem to support the recent claim that Gestalts are processed less efficiently than part stimuli. Inspired by this, we sketch how contrast manipulations could be an additional tool to study how Gestalts are processed.

Situation-specific theory of surgical site infection-related stimuli in patients undergoing heart transplantation

Background and objective: Heart transplant is a life-saving treatment and currently is the definitive gold-standard in the treatment of refractory heart failure. Surgical site infection is a serious complication of heart transplantation. A nursing theory predicting consequences related to the management of risk factors for surgical site infection in patients undergoing heart transplantation can be useful to nursing practice. The objective of this study was to develop a situation-specific theory of surgical site infection-related stimuli in patients undergoing heart transplantation.Methods: It was adopted an integrative strategy to develop the theory. Multiple sources of knowledge were accessed. The Roy Adaptation Model was adopted as the foundation for the development of this situation-specific theory in a nursing perspective. A literature review on risk factors for surgical site infection in patients undergoing heart transplantation was conducted. By configuring those sources with practice expertise in a collaborative effort, risk factors for surgical site infection in patients undergoing heart transplantation were classified as contextual or residual stimuli, focal stimulus was defined, and seven theory propositions were developed.Results: Heart transplant surgery was considered as focal stimulus. The contextual stimuli were classified as preoperative, intraoperative, and postoperative contextual stimuli. The residual stimuli were classified as preoperative and intraoperative residual stimuli. No postoperative residual stimulus was identified. Ten theory propositions were created.Conclusions: The emerging theory can help nurses to prevent surgical site infections in patients undergoing heart transplantation. Further developments must be made in order to consider nurse-patient interactions during the prevention of surgical site infections.

The role of ambient sound levels, signal-to-noise ratio, and stimulus pulse rate on behavioural disturbance of seabass in a net pen

Anthropogenic sources increasingly contribute to the underwater soundscape and this may negatively impact aquatic life, including fish. Anthropogenic sound may mask relevant sound, alter behaviour, physiology, and may lead to physical injury. Behavioural effect studies are often seen as critical to evaluate individual and population-level impact. However, behavioural responsiveness likely depends on context and characteristics of sound stimuli. We pose that ambient sound levels, signal-to-noise ratio (SNR), and pulse rate interval (PRI), could affect the behavioural response of fish. To study this, we experimentally exposed groups of tagged European seabass (Dicentrarchus labrax) to different impulsive sound treatments that varied in pulse level, elevated background level, SNR, and PRI. Upon sound exposure, the seabass increased their swimming depth. The variation in the increase in swimming depth could not be attributed to pulse level, background level, SNR or PRI. It may be that the current range of sound levels or PRIs was too narrow to find such effects.

An examination of the Kuleshov effect using still photographs.

The goal of the present study was to examine whether the effect of visual context on the interpretation of facial expression from an actor’s face could be produced using isolated photographic stills, instead of the typical dynamic film sequences used to demonstrate the effect. Two-photograph sequences consisting of a context photograph varying in pleasantness and a photograph of an actor’s neutral face were presented. Participants performed a liking rating task for the context photograph (to ensure attention to the stimulus) and they performed three tasks for the face stimulus: labeling the emotion portrayed by the actor, rating valence, and rating arousal. The results of the labeling data confirmed the existence of a visual context effect, with more faces labeled as “happy” after viewing pleasant context and more faces labeled “sad” or “fearful” after viewing unpleasant context. This effect was demonstrated when no explicit connection between the context stimulus and face stimulus was invoked, with the contextual information exerting its effect on labeling after being held in memory for at least 10 seconds. The results for ratings of valence and arousal were mixed. Overall, the results suggest that isolated photograph sequences produce a Kuleshov-type context effect on attributions of emotion to actors’ faces, replicating previous research conducted with dynamic film sequences.

Electroactive Smart Materials: Novel Tools for Tailoring Bacteria Behavior and Fight Antimicrobial Resistance.

Despite being very simple organisms, bacteria possess an outstanding ability to adapt to different environments. Their long evolutionary history, being exposed to vastly different physicochemical surroundings, allowed them to detect and respond to a wide range of signals including biochemical, mechanical, electrical, and magnetic ones. Taking into consideration their adapting mechanisms, it is expected that novel materials able to provide bacteria with specific stimuli in a biomimetic context may tailor their behavior and make them suitable for specific applications in terms of anti-microbial and pro-microbial approaches. This review maintains that electroactive smart materials will be a future approach to be explored in microbiology to obtain novel strategies for fighting the emergence of live threatening antibiotic resistance.

Mitigating resurgence of destructive behavior using the discriminative stimuli of a multiple schedule.

Results of several recent translational studies have suggested that correlating contextual or discriminative stimuli with the delivery and withholding of reinforcement for the functional communication response (FCR) may mitigate resurgence of destructive behavior, but few, if any, have isolated the effects of those stimuli. In the present study, we first trained the FCR, brought it under stimulus control of a multiple schedule, and thinned its reinforcement schedule in one stimulus context. Next, we conducted resurgence evaluations (i.e., baseline, functional communication training [FCT], extinction challenge) in two novel contexts to test the effects of the discriminative stimuli on resurgence. We programmed one context to include the (a) SD during the FCT phase to signal the availability of reinforcement for the FCR and (b) SΔ during a subsequent extinction challenge to signal the unavailability of reinforcement for the FCR. The other context did not include the SD during the FCT phase, nor the SΔ during the extinction challenge. We expected to see greater persistence of the FCR in the context that included the SD during FCT and less persistence of the FCR and less resurgence of destructive behavior in the context that included the SΔ during the extinction challenge. Obtained results confirmed this latter prediction, but we observed no reliable difference when the SD was present or absent during the FCT phase. Our results have relevance for practitioners in that they provide further empirical support for the use of discriminative stimuli when treating destructive behavior.

Constrained inference in sparse coding reproduces contextual effects and predicts laminar neural dynamics.

When probed with complex stimuli that extend beyond their classical receptive field, neurons in primary visual cortex display complex and non-linear response characteristics. Sparse coding models reproduce some of the observed contextual effects, but still fail to provide a satisfactory explanation in terms of realistic neural structures and cortical mechanisms, since the connection scheme they propose consists only of interactions among neurons with overlapping input fields. Here we propose an extended generative model for visual scenes that includes spatial dependencies among different features. We derive a neurophysiologically realistic inference scheme under the constraint that neurons have direct access only to local image information. The scheme can be interpreted as a network in primary visual cortex where two neural populations are organized in different layers within orientation hypercolumns that are connected by local, short-range and long-range recurrent interactions. When trained with natural images, the model predicts a connectivity structure linking neurons with similar orientation preferences matching the typical patterns found for long-ranging horizontal axons and feedback projections in visual cortex. Subjected to contextual stimuli typically used in empirical studies, our model replicates several hallmark effects of contextual processing and predicts characteristic differences for surround modulation between the two model populations. In summary, our model provides a novel framework for contextual processing in the visual system proposing a well-defined functional role for horizontal axons and feedback projections.