Stimulus Rate Research Articles

Cortical functionality during reversal learning on a decision-making task in young men

The evaluation of external and internal stimuli permits the ongoing actualization of choice-related information and, thus, the association between stimuli and outcomes. This process is essential to decision-making as it allows constant adaptation to environmental changes in order to maximize gains and minimize losses. Reversal learning paradigms are used to study this process, which has been associated with prefrontal cortex activity (frontopolar, dorsolateral) in conjunction with posterior areas (parietal, temporal), due to their participation in integrating and processing the stimuli-reward relation. The aim of this study was to assess the cortical functionality associated with reversal learning during the decision-making process. The EEG activity of 22 young men was recorded while performing a decision-making task in a reversal learning condition compared to an initial learning condition. EEG data were analyzed during evaluation of the stimuli, before motor execution (formation of preferences), and during task feedback (outcome evaluation). The formation of preferences stage was characterized by a higher correlation of the alpha2 band between the parietal cortices. In the feedback stage of the reversal learning condition, a higher absolute power of the theta band in the left dorsolateral (F3), and a lower correlation of the alpha1 band between the right frontopolar and dorsolateral (Fp2-F4), as well as between the right frontopolar and temporal (Fp2-T4), were observed. The data obtained show that the EEG activity of the areas recorded changed in the evaluation of the stimuli information in the reversal learning condition during a decision-making task.

Effect of stimulation parameters on sequential current-steered stimuli in cochlear implants.

Manipulation of cochlear implant (CI) place pitch was carried out with current steering by stimulating two CI electrodes sequentially. The objective was to investigate whether shifts in activated neural populations could be achieved to produce salient pitch differences and to determine which stimulation parameters would be more effective in steering of current. These were the pulse rate and pulse width of electrical stimuli and the distance between the two current-steering electrodes. Nine CI users participated, and ten ears were tested. The pattern of pitch changes was not consistent across listeners, but the data suggest that individualized selection of stimulation parameters may be used to effect place pitch changes with sequential current steering. Individual analyses showed that pulse width generally had little influence on the effectiveness of current steering with sequential stimuli, while more salient place pitch shifts were often achieved at wider electrode spacing or when the stimulation pulse rate was the same as that indicated on the clinical MAP (the set of stimulation parameters) of the listener. Results imply that current steering may be used in CIs that allow only sequential stimulation to achieve place pitch manipulation.

Cross-modal Transfer of Valence or Arousal from Music to Word Targets in Affective Priming?

ABSTRACT This registered report considers how emotion induced in an auditory modality (music) can influence affective evaluations of visual stimuli (words). Specifically, it seeks to determine which emotional dimension is transferred across modalities – valence or arousal – or whether the transferred dimension depends on the focus of attention (feature-specific attention allocation). Two experiments were carried out. The first was an affective priming paradigm that will allow for the orthogonal manipulation of valence and arousal in both the words and music, alongside a manipulation to direct participants’ attention to either the valence or the arousal dimension. Secondly, a lexical decision task allowed cross-modal transfer of valence and arousal to be probed without the focus of participants’ attention being manipulated. Congruence effects were present in the affective priming task – valence was transferred in both the valence and arousal tasks, whereas arousal was transferred in the arousal task only. Contrary to predictions, the lexical decision task did not exhibit any congruence effects.

Brain and behavioral contributions to individual choices in response to affective-cognitive persuasion.

Affective and cognitive information conveyed by persuasive stimuli is evaluated and integrated by individuals according to their behavioral predispositions. However, the neurocognitive structure that supports persuasion based on either affective or cognitive content is poorly understood. Here, we examine the neural and behavioral processes supporting choices based on affective and cognitive persuasion by integrating 4 information processing features: intrinsic brain connectivity, stimulus-evoked brain activity, intrinsic affective-cognitive orientation, and explicit target evaluations. We found that the intrinsic cross-network connections of a multimodal fronto-parietal network are associated with individual affective-cognitive orientation. Moreover, using a cross-validated classifier, we found that individuals' intrinsic brain-behavioral dimensions, such as affective-cognitive orientation and intrinsic brain connectivity, can predict individual choices between affective and cognitive targets. Our findings show that affective- and cognitive-based choices rely on multiple sources, including behavioral orientation, stimulus evaluation, and intrinsic functional brain architecture.

State or trait: the neurobiology of anorexia nervosa — contributions of a functional magnetic resonance imaging study

BackgroundThe understanding of the cerebral neurobiology of anorexia nervosa (AN) with respect to state- versus trait-related abnormalities is limited. There is evidence of restitution of structural brain alterations with clinical remission. However, with regard to functional brain abnormalities, this issue has not yet been clarified.MethodsWe compared women with AN (n = 31), well-recovered female participants (REC) (n = 18) and non-patients (NP) (n = 27) cross-sectionally. Functional magnetic resonance imaging was performed to compare neural responses to food versus non-food images. Additionally, affective ratings were assessed.ResultsFunctional responses and affective ratings did not differ between REC and NP, even when applying lenient thresholds for the comparison of neural responses. Comparing REC and AN, the latter showed lower valence and higher arousal ratings for food stimuli, and neural responses differed with lenient thresholds in an occipital region.ConclusionsThe data are in line with some previous findings and suggest restitution of cerebral function with clinical recovery. Furthermore, affective ratings did not differ from NP. These results need to be verified in intra-individual longitudinal studies.

Stimulus evaluation in the eye of the beholder: Big Five personality traits explain variance in normed picture sets

The use of normed picture sets has become the gold standard in the study of affect, emotion, or attitudes. However, normed picture sets not only show the intended variance between pictures, but for each picture, normed ratings also show substantial variance between persons. Here, we examine whether interindividual variance in the pictures’ evaluations is systematic and associated with personality traits. In a large-scale preregistered study, a heterogeneous sample of English- and German-speaking participants (total N = 901) completed a Big Five questionnaire and evaluated pictures of positive, neutral, and negative average valence from the OASIS database. The findings show that self-reported Neuroticism, Extraversion, and Agreeableness are associated with individual differences in picture evaluations, which supports and extends previous theorizing on personality and affect. Our results suggest that individual differences observed in paradigms employing valenced pictures may come from individual differences in picture evaluations rather than the processes under study.

There is no place like home: home satisfaction and customer satisfaction in online grocery retailing

ABSTRACT This study acknowledges that home is a central and valenced place for most people, and therefore it is assumed that (a) the content in people’s general category for home issues can be activated easily, particularly by various home-related stimuli, and that (b) the affective charge of such content can have a valence-congruent impact on evaluations of home-related stimuli. These assumptions were the basis for two empirical studies carried out in an online grocery shopping context with respect to home delivery. Both studies indicate that home satisfaction had a positive influence on satisfaction with home delivery – and that home satisfaction had an indirect and positive influence of overall satisfaction with the retailer that provides home delivery. These findings, then, emphasize the need to ‘emplace’ the contemporary online shopper: although the shopper faces an abundance of alternatives only a mouse-click away, he or she is still emplaced in an environment when orders are placed and when goods are received. And when this environment is home, it is particularly likely to influence home-related offers.

Accumulation and control of spin waves in magnonic dielectric microresonators by a comb of ultrashort laser pulses.

Spin waves in magnetic microresonators are at the core of modern magnonics. Here we demonstrate a new method of tunable excitation of different spin wave modes in magnetic microdisks by using a train of laser pulses coming at a repetition rate higher than the decay rate of spin precession. The microdisks are etched in a transparent bismuth iron garnet film and the light pulses influence the spins nonthermally through the inverse Faraday effect. The high repetition rate of the laser stimulus of 10 GHz establishes an interplay between the spin wave resonances in the frequency and momentum domains. As a result, scanning of the focused laser spot near the disk boarder changes interference pattern of the magnons and leads to a resonant dependence of the spin wave amplitude on the external magnetic field. Apart from that, we achieved a switching between volume and surface spin waves by a small variation of the external magnetic field.

The relationship of muscular endurance and coordination and dexterity with behavioral and neuroelectric indices of attention in preschool children

This study investigated the associations of non-aerobic fitness (NAF) and motor competence (MC) with attention in 4–6 year-old preschoolers. The allocation of attentional resources and speed of stimulus categorization were examined using the amplitude and latency of P3 of event-related potentials respectively, while cortical activation related to general attention and task-specific discriminative processes were examined using event-related desynchronization (ERD) at lower (8–10 Hz) and upper (10–12 Hz) alpha frequencies, respectively. Seventy-six preschoolers completed NAF (muscular power, muscular endurance, flexibility, balance) and MC (coordination and dexterity, ball skills, agility and balance) test batteries. Electroencephalogram was recorded while participants performed an auditory oddball task. After controlling for age and MC, muscular endurance was positively related to P3 amplitude. MC and its coordination and dexterity sub-component were positively related to task performance, with higher levels of coordination and dexterity showing an additional association with greater upper alpha ERD between 700 and 1000 ms following stimulus onset after controlling for age and NAF. These findings suggest relationships of NAF and MC with early childhood neurocognitive function. Specifically, muscular endurance is related to the neuroinhibition in facilitating effective allocation of attentional resources to stimulus evaluation while coordination and dexterity are related to cortical activation underlying strategic attentional preparation for subsequent stimulus evaluation.

Devaluation of NoGo stimuli is both robust and fragile

ABSTRACT Consistently not responding to stimuli during go/no-go training leads to lower evaluations of these NoGo stimuli. How this NoGo-devaluation-effect can be explained has remained unclear. Here, we ran three experiments to test the hypothesis that people form stimulus-stop-associations during the training, which predict the strength of the devaluation-effect. In Experiment 1, we tried to simultaneously measure the stimulus-stop-associations and NoGo-devaluation, but we failed to find these effects. In Experiment 2, we measured NoGo-devaluation with established procedures from previous work, and stimulus-stop-associations with a novel separate task. Results revealed a clear NoGo-devaluation-effect, which remained visible across multiple rating blocks. Interestingly, this devaluation-effect disappeared when stimulus-stop-associations were measured before stimulus evaluations, and there was no evidence supporting the formation of the stimulus-stop-associations. In Experiment 3, we found evidence for the acquisition of stimulus-stop-associations using an established task from previous work, but this time we found no subsequent NoGo-devaluation-effect. The present research suggests that the NoGo-devaluation-effect and stimulus-stop-associations can be found with standard established procedures, but that these effects are very sensitive to alterations of the experimental protocol. Furthermore, we failed to find evidence for both effects within the same experimental protocol, which has important theoretical and applied implications.

The role of causal structure in implicit evaluation

Causal relationships, unlike mere co-occurrence, allow humans to obtain rewards and avoid punishments by intervening on their environment. Accordingly, explicit (controlled) evaluations of stimuli encountered in the environment are known to be sensitive to causal relationships above and beyond mere co-occurrence. In this project, we conduct stringent tests of whether implicit (automatic) evaluation also reflects causal relationships and begin to probe the representational mechanisms underlying such sensitivity. Participants (N = 4836) observed causal events during which two stimuli were equally contingent with positive or negative outcomes but only one of them was causally responsible for these outcomes. Across 6 studies, varying in design and amount of verbal scaffolding provided, differences in causal status consistently guided not only explicit measures of evaluation (Likert and slider scales; Bayes Factor meta-analysis: Cohen's d = 0.28, BF10 > 1046) but also their implicit counterparts (Implicit Association Tests; Bayes Factor meta-analysis: Cohen's d = 0.22, BF10 > 1029). However, unlike their explicit counterparts, implicit evaluations were not sensitive to causal relationships that had to be flexibly derived by combining disparate past experiences. Taken together, these studies suggest that implicit evaluations are sensitive to causal information. Such sensitivity seems to be mediated via precompiled, causally informed value representations rather than online computations over a causal model.

Children with amblyaudia show less flexibility in auditory cortical entrainment to periodic non-speech sounds

We investigated auditory temporal processing in children with amblyaudia (AMB), a subtype of auditory processing disorder, via cortical neural entrainment. Evoked responses were recorded to click-trains at slow versus fast (8.5 versus 14.9/sec) rates in n = 14 children with AMB and n = 11 age-matched controls. Source and time-frequency analyses decomposed EEGs into oscillations (reflecting neural entrainment) stemming from the bilateral auditory cortex. Phase-locking strength in AMB depended critically on the speed of auditory stimuli. In contrast to age-matched peers, AMB responses were largely insensitive to rate manipulations. This rate resistance was seen regardless of the ear of presentation and in both cortical hemispheres. Children with AMB show a stark inflexibility in auditory cortical entrainment to rapid sounds. In addition to reduced capacity to integrate information between the ears, we identify a new functional characterization of AMB in the form of more rigid tagging of external auditory stimuli. Our neurophysiological findings may account for certain temporal processing deficits commonly observed in AMB and related auditory processing disorders (APDs) behaviorally. More broadly, our findings may inform communication strategies and future rehabilitation programs; increasing the rate of stimuli above a normal (slow) speech rate is likely to make stimulus processing more challenging for individuals with AMB/APD.

Conceptual generalisation in fear conditioning using single and multiple category exemplars as conditional stimuli – electrodermal responses and valence evaluations generalise to the broader category

ABSTRACT Conceptual generalisation occurs when conditional responses generalise to novel stimuli from the same category. Past research demonstrates that physiological fear responses generalise across categories, however, conceptual generalisation of stimulus valence evaluations during fear conditioning has not been examined. We investigated whether conceptual generalisation, as indexed by electrodermal responses and stimulus evaluations, would occur, and differ after training with single or multiple conditional stimuli (CSs). Stimuli from two of four categories (vegetables, farm animals, clothing, and office supplies) were used as the CS+ (followed by an electric stimulus) or CS- (presented alone). Generalisation was assessed by presenting novel stimuli from the CS categories after acquisition, extinction, and reinstatement. One category exemplar was used as the CS+ and CS- in the single group, whereas three exemplars were used as the CS+ and CS- in the multiple group. Electrodermal responses generalised in acquisition and extinction but did not differ between groups. In the multiple group, CS evaluations generalised in acquisition and extinction, whereas generalisation was not evident in the single group. Training with multiple CSs also resulted in the extinction of stimulus valence. The current findings have implications for future research examining the generalisation of valence and for exposure-based treatments of anxiety.

Observational evaluative conditioning is sensitive to relational information.

Social learning represents an important avenue via which evaluations can be formed or changed. Rather than learning slowly through trial and error, we can instead observe how another person (a "model") interacts with stimuli and quickly adjust our own behaviour. We report five studies (n = 912) that focused on one subtype of social learning, observational evaluative conditioning (OEC), and how it is moderated by relational information (i.e., information indicating how a stimulus and a model's reactions are related). Participants observed a model reacting positively to one stimulus and negatively to another, and were either told that these reactions were genuine, faked, or opposite to the model's actual feelings. Stimulus evaluations were then indexed using ratings and a personalised Implicit Association Test (pIAT). When the model's reactions were said to be genuine, OEC effects emerged in the expected direction. When the model's reactions were said to be faked, the magnitude of self-reported, but not pIAT, effects was reduced. Finally, stating that the model's reactions were opposite to his actual feelings eliminated or reversed self-reported effects and eliminated pIAT effects. We consider how these findings relate to previous work as well as mental-process theories.

Classical Conditioning for Pain: The Development of a Customized Single-Case Experimental Design

Single-case experiments are increasingly popular in the behavioral sciences. Due to their flexibility, single-case designs can be customized to test a variety of experimental hypotheses. We were interested in using a single-case experimental approach to test whether pain thresholds can be influenced by Pavlovian classical conditioning. Following the example of earlier studies into this topic, we planned to measure whether participants would more frequently report specific electrocutaneous stimuli as painful when they were presented with specific vibrotactile stimuli that had previously been associated with painful electrocutaneous stimuli. First, we decided on a mean difference effect size measure derived from the Sensation and Pain Rating Scale ratings for the electrocutaneous stimuli provided by the participants. Next, we discussed several possible single-case designs and evaluated their benefits and shortcomings. Then, we ran pilot tests with a few participants based on the possible single-case designs. We also conducted a simulation study to estimate the power of a randomization test to test our hypothesis using different values for effect size, number of participants, and number of measurements. Finally, we decided on a sequentially replicated AB phase design with 30 participants based on the results from the pilot tests and the power study. We plan to implement this single-case design in a future experiment to test our hypothesis

Auditory experience modulates fronto-parietal theta activity serving fluid intelligence.

Children who are hard of hearing are at risk for developmental language and academic delays compared with children with normal hearing. Some work suggests that high-order cognitive function, including fluid intelligence, may relate to language and academic outcomes in children with hearing loss, but findings in these studies have been mixed and to date, there have been no studies of the whole-brain neural dynamics serving fluid intelligence in the context of hearing loss. To this end, this study sought to identify the impact of hearing loss and subsequent hearing aid use on the neural dynamics serving abstract reasoning in children who are hard of hearing relative to children with normal hearing using magnetoencephalography. We found significant elevations in occipital and parietal theta activity during early stimulus evaluation in children who are hard of hearing relative to normal-hearing peers. In addition, we found that greater hearing aid use was significantly related to reduced activity throughout the fronto-parietal network. Notably, there were no differences in alpha dynamics between groups during later-stage processing nor did alpha activity correlate with hearing aid use. These cross-sectional data suggest that differences in auditory experience lead to widespread alterations in the neural dynamics serving initial stimulus processing in fluid intelligence in children.

Classically conditioned modulation of pain depends on stimulus intensity

Innocuous cues that become associated with pain can enhance pain. This is termed classically conditioned hyperalgesia. The size of this effect varies under different conditions. We aimed to test whether the sensitising effect of pain-associated cues depends on the intensity of the paired test stimulus. To do this, two virtual reality environments were paired with either painful or non-painful vibrotactile stimuli in a counterbalanced fashion. The differential effect of the two environments was evaluated using pain intensity ratings of paired electrocutaneous test stimuli at three different intensity levels. Forty healthy participants were included in the study; 30 participants experienced sufficient pain during the learning phase and were included in the main analysis. An effect of environment (p = 0.014) and interaction between environment and test stimulus intensity was found (p = 0.046). Only the most intense test stimulus was modulated by environment. While the effect was small, the results are consistent with the proposition that pain-associated cues may induce hyperalgesia to some degree, under certain conditions. In particular, results highlight the potential relevance of stimulus intensity during and after the initial painful experience. Further attention is needed to comprehensively understand the variables that impact classically conditioned hyperalgesia.

Investigating the relationship between background luminance and self-reported valence of auditory stimuli

The present study investigated the effect of background luminance on the self-reported valence ratings of auditory stimuli, as suggested by some earlier work. A secondary aim was to better characterise the effect of auditory valence on pupillary responses, on which the literature is inconsistent. Participants were randomly presented with sounds of different valence categories (negative, neutral, and positive) obtained from the IADS-E database. At the same time, the background luminance of the computer screen (in blue hue) was manipulated across three levels (i.e., low, medium, and high), with pupillometry confirming the expected strong effect of luminance on pupil size. Participants were asked to rate the valence of the presented sound under these different luminance levels. On a behavioural level, we found evidence for an effect of background luminance on the self-reported valence rating, with generally more positive ratings as background luminance increased. Turning to valence effects on pupil size, irrespective of background luminance, interestingly, we observed that pupils were smallest in the positive valence and the largest in negative valence condition, with neutral valence in between. In sum, the present findings provide evidence concerning a relationship between luminance perception (and hence pupil size) and self-reported valence of auditory stimuli, indicating a possible cross-modal interaction of auditory valence processing with completely task-irrelevant visual background luminance. We furthermore discuss the potential for future applications of the current findings in the clinical field.

The attenuation of spider avoidance action tendencies in spider-fearful individuals and its impact on explicit evaluation of spider stimuli

Researchers have demonstrated that individuals with heightened levels of spider-fear, as compared to relatively lower levels of spider-fear, are characterised a pattern of action tendencies that facilitates the speed to complete ‘avoidance’ movements, as compared to ‘approach movements, in the face of spider-stimuli. However, research has not determined whether such tendencies are able to be manipulated, and the impact of their manipulation, in individuals with heightened spider-fear. Seventy-one participants who reported relatively high levels of spider-fear completed an action tendency manipulation procedure. The procedure was designed to attenuate avoidance action tendencies, by repeatedly requiring completion of approach actions in response to images of spiders (Approach Spider Condition), or to have no impact on action tendencies (Control Condition). Participants completed an assessment of approach and avoidance action tendencies to images of spiders and butterflies, and rated the unpleasantness and disgust of images of spiders and butterflies, before and after completion of the manipulation procedure. Analyses revealed that avoidance action tendencies to spider stimuli were attenuated in the Approach Spider Condition as compared to the Control Condition as intended. However, conditions did not differ in the evaluation of spider stimuli following the manipulation procedure. The findings demonstrate that avoidance action tendencies to spider stimuli can be manipulated amongst individuals with heightened spider-fear, though their manipulation does not lead to change in explicit evaluation of spider stimuli. The implications of these findings and avenues for future research are discussed.

Verbalisation of attention regulation strategies and background music enhance extinction learning and retention

Relapse and return of fear are common following exposure-based treatments which aim to decrease anxiety by reducing danger expectancies and negative stimulus evaluations. Using Pavlovian conditioning and extinction procedures, recent studies found that verbalising catchphrases to prompt attention to, and memory of, stimulus contingencies during extinction prevented US expectancy generalisation to safe stimuli and reduced anxiety ratings. Verbalizations did not improve negative evaluations of conditional stimuli. Given that negative evaluations predict return of fear, the current study examined whether verbalisation strategies combined with listening to liked, non-lyrical background music enhanced expectancy learning and positively changed stimulus evaluations. A differential Pavlovian conditioning procedure was used involving fear acquisition, extinction, and extinction retest phases. Participants were assigned to a verbalisation condition (N = 21), a verbalisation plus liked, non-lyrical music condition (N = 21) or a control condition (N = 21) during extinction. The verbalisation strategies, with and without music, prevented the generalisation of US expectancies to safe stimuli at retest. Verbalisation strategies plus music increased positive evaluations of conditional stimuli during extinction and retest. Further research on the role of verbalising attention regulation strategies and liked, non-lyrical background music during extinction is warranted with clinical samples.