Stimulus Onset Asynchrony Research Articles

The Effect of SOA on An Asynchronous ERP and VEP-Based BCI

Our previous study established an asynchronous BCI system by using the oddball paradigm to simultaneously induce event-related potentials (ERPs) and visual evoked potentials (VEPs) (E-V BCIs). We found that stimulus onset asynchrony (SOA) is an important factor for performance since it significantly affects the ERP and VEP. Increasing the SOA increases the ERP, which improves the accuracy of detecting target stimuli. However, a larger SOA leads to a lower VEP frequency, which causes the VEP to have poor accuracy when discriminating between the brain states. How to balance the two potentials and accuracies is a problem. This study established eight SOAs from 100 ms to 375 ms that were composed of different interstimulus intervals and the same stimulus duration of 80 ms. We used a probability-based Fisher linear discriminant analysis (P-FLDA) classifier to calculate the classification accuracies of the ERP-based visual speller, VEP-based brain state discrimination, and E-V BCI. The results show that as the SOA increases, the amplitudes of N200 and P300 increase, and the accuracy also shows an increasing trend. However, the frequency of the VEP and the accuracies of state discrimination show downward trends. The change in accuracies of the E-V BCI system combining these two parts is nonlinear, and the SOA optimal value is 125 ms. The SOA of 125 ms yields the best accuracies of 95.83% and practical bit rate of 57.17 bits/min in the E-V BCI system, which provides a guideline for selecting the SOA to improve the performance.

Deaf and Hard of Hearing Students' Configurational and Phonological Processing in Chinese One- and Two-Character Word Recognition.

To examine deaf and hard of hearing (DHH) students' configurational and phonological processing in Chinese one- and two-character word recognition, two experiments were conducted in a primed semantic categorization task. Configurational priming was observed in DHH participants' reaction times (RTs) at the SOA (stimulus onset asynchrony) of 47 ms and in their probability of making erroneous responses at SOAs of 47 and 187 ms in Experiment 1. Phonological priming was revealed in hearing and DHH participants' probability of making erroneous responses in Experiment 2. Hearing participants' RTs indicated facilitation and inhibition at the SOAs of 47 and 187 ms, respectively; DHH participants' RTs showed priming at the SOA of 187 ms. It is concluded that DHH college students are more likely to use the configurational information but less likely to use the phonological information than hearing college students in one- and two-character word recognition.

어휘접근 과정에서 나타나는 한국인 L2 학습자의 이중언어 음운적 동시활성화 양상

This study explored the likelihood of cross-language co-activation among Korean L2 learners of English when performing a monolingual phoneme monitoring task. The stimulus onset asynchrony (SOA: -2,000ms, +200ms, +400ms) between picture and target phoneme stimuli were manipulated. Results demonstrated that participants responded faster and showed lower error rates when performing the task in L1 compared to L2. Moreover, interference effects were observed in all three SOA-manipulated experiments irrelevant to the language type, which shows the presence of phonological co-activation of the language not- in-use during monolingual task. Stronger L1 interference effect was shown during L2 task, which reflects the difference in the degree of bilingual phonological co-activation. This study suggests that when given a short period of time to access the semantic system which is shared by two languages, phonological information of both languages are co-activated even for non-proficient L2 learners whose languages have different scripts.

Common principles underlie the fluctuation of auditory and visual sustained attention.

Sustained attention plays an important role in adaptive behaviours in everyday activities. As previous studies have mostly focused on vision, and attentional resources have been thought to be specific to sensory modalities, it is still unclear how mechanisms of attentional fluctuations overlap between visual and auditory modalities. To reduce the effects of sudden stimulus onsets, we developed a new gradual-onset continuous performance task (gradCPT) in the auditory domain and compared dynamic fluctuation of sustained attention in vision and audition. In the auditory gradCPT, participants were instructed to listen to a stream of narrations and judge the gender of each narration. In the visual gradCPT, they were asked to observe a stream of scenery images and indicate whether the scene was a city or mountain. Our within-individual comparison revealed that auditory and visual attention are similar in terms of the false alarm rate and dynamic properties including fluctuation frequency. Absolute timescales of the fluctuation in the two modalities were comparable, notwithstanding the difference in stimulus onset asynchrony. The results suggest that fluctuations of visual and auditory attention are underpinned by common principles and support models with a more central, modality-general controller.

Testing the Process Dissociation Procedure by Behavioral and Neuroimaging Data: The Establishment of the Mutually Exclusive Theory and the Improved PDP.

The process dissociation procedure (PDP) of implicit sequence learning states that the correct inclusion-task response contains the incorrect exclusion-task response. However, there has been no research to test the hypothesis. The current study used a single variable (Stimulus Onset Asynchrony SOA: 850 ms vs. 1350 ms) between-subjects design, with pre-task resting-state fMRI, to test and improve the classical PDP to the mutually exclusive theory (MET). (1) Behavioral data and neuroimaging data demonstrated that the classical PDP has not been validated. In the SOA = 850 ms group, the correct inclusion-task response was at chance, but the incorrect exclusion-task response occurred greater than chance. In the SOA = 850 ms group, the two responses were not correlated, but in the SOA = 1,350 ms group and putting the two groups together, the two responses were in contrast to each other. In each group, brain areas whose amplitude of low frequency fluctuations (ALFFs) in the resting-state related to the two responses were either completely different or opposite to one another. However, the results were perfectly consistent with the MET proposed by the present study which suggests that the correct inclusion-task response is equal to the correct exclusion-task response is equal to C + A1, and the incorrect exclusion-task response is equal to A2. C denotes the controlled response and A1 and A2 denote two different automatic responses. (2) The improved PDP was proposed to categorize the 12 kinds of triplets as delineating four knowledge types, namely non-acquisition of knowledge, uncontrollable knowledge, half-controllable knowledge, and controllable knowledge with the MET. ALFFs in the resting-state could predict the four knowledge types of the improved PDP among two groups. The participants’ control of the four knowledge types (degree of consciousness) gradually improved. Correspondingly, the brain areas in the resting-state positively related to the four knowledge types, gradually changed from the sensory and motor network to the somatic sensorimotor network, and then to the implicit learning network, and then to the consciousness network. The brain areas in the resting-state negatively related to the four knowledge types gradually changed from the consciousness network to the sensory and motor network. As SOA increased, the brain areas associated with almost all the four knowledge types changed. (3) The inhomogeneous hypothesis of the MET is best suited to interpret behavioral and neuroimaging data; it states that the same components among the four knowledge types are not homogeneous, and the same knowledge types are not homogeneous between the two SOA groups.

Response competition better explains Stroop interference than does response exclusion

Researchers debate whether Stroop interference from an incongruent word in color-naming response time is caused by response competition or by response exclusion. According to the former account, the interference reflects competition in lexical response selection during color name planning, whereas according to the latter, the interference reflects the removal of a motor program for the incongruent word from an articulatory buffer after planning. Here, numerical predictions about the magnitude of Stroop interference as a function of stimulus onset asynchrony were derived from these accounts. These predictions were then tested on representative data in the literature. Measures of goodness-of-fit showed that the numerical predictions of a response competition account are closer to the empirical data than those of the response exclusion account. These results indicate that response competition provides a better explanation of interference in naming than does response exclusion.

Cortical Distance but Not Physical Distance Modulates Attentional Rhythms.

It has been well documented that the spotlight of attention is intrinsically rhythmic and oscillates by discretely sampling either single or multiple objects. However, the neural site of attentional rhythms remains poorly understood. Considering the topography of visual cortical areas, we modulated the cortical distances of two gratings while fixing the corresponding retinal distance by setting the gratings on different sides (cortically far, Experiment 1) or on the same side (cortically near, Experiment 2) of the vertical median, to investigate the interhemispheric divide effect in attentional rhythms. The cue-target stimulus onset asynchrony (SOA) varied from 0.1 s to 1.08 s in 20-ms increments, allowing fluctuations below 50 Hz to be examined. The results showed that when the two stimuli were on opposite sides of the vertical meridian, attentional rhythms were observed at theta and alpha frequencies, consistent with the results reported in previous studies. However, when the two stimuli were located on the same side of the vertical meridian, attentional rhythms were not observed. This study indicates that attentional rhythms are modulated by cortical distance but not by physical distance.

Balancing cognitive and environmental constraints when deciding to switch tasks: Exploring self-reported task-selection strategies in self-organised multitasking.

We investigated how people balance cognitive constraints (switch costs) against environmental constraints (stimulus availabilities) to optimise their voluntary task switching performance and explored individual differences in their switching behaviour. Specifically, in a self-organised task-switching environment, the stimulus needed for a task repetition was delayed by a stimulus-onset asynchrony (SOA) that increased with each consecutive repetition until a task switch reset the SOA. As predicted, participants switched tasks when the SOA in task switches approximately matched their individual switch costs and thus they optimised local task performance. Interestingly, self-reports (confirmed by behavioural switching patterns) revealed two individual strategies: some participants (N = 34) indicated to guide their task selection behaviour based on preplanned task sequences over several trials, whereas others (N = 42) indicated to primarily decide on a trial-by-trial basis whether to switch or to repeat tasks. Exploration of switching behaviour based on the two strategy groups revealed additional insights into how people achieved adaptive task selection behaviour in this task environment. Overall, the present findings suggest that individuals select tasks with the aim of improving task performance when dealing with multiple task requirements, but they differ in their preferred individual task selection strategies.

Seeing a Page in a Flipbook: Shorter Visual Temporal Integration Windows in 2‐Year‐Old Toddlers with Autism Spectrum Disorder

Individuals with autism spectrum disorder (ASD) experience differences in visual temporal processing, the part of vision responsible for parsing continuous input into discrete objects and events. Here we investigated temporal processing in 2-year-old toddlers diagnosed with ASD and age-matched typically developing (TD) toddlers. We used a visual search task where the visibility of the target was determined by the pace of a display sequence. On integration trials, each display viewed alone had no visible target, but if integrated over time, the target became visible. On segmentation trials, the target became visible only when displays were perceptually segmented. We measured the percent of trials when participants fixated the target as a function of the stimulus onset asynchrony (SOA) between displays. We computed the crossover point of the integration and segmentation performance functions for each group, an estimate of the temporal integration window (TIW), the period in which visual input is combined. We found that both groups of toddlers had significantly longer TIWs (125 ms) than adults (65 ms) from previous studies using the same paradigm, and that toddlers with ASD had significantly shorter TIWs (108 ms) than chronologically age-matched TD controls (142 ms). LAY SUMMARY: We investigated how young children, with and without autism, organize dynamic visual information across time, using a visual search paradigm. We found that toddlers with autism had higher temporal resolution than typically developing (TD) toddlers of the same age - that is, they are more likely to be able to detect rapid change across time, relative to TD toddlers. These differences in visual temporal processing can impact how one sees, interprets, and interacts with the world. Autism Res 2021, 14: 946-958. © 2020 International Society for Autism Research and Wiley Periodicals LLC.

The role of attentional slippage in Stroop dilution.

The present study examined the cognitive locus of Stroop dilution using a psychological refractory period (PRP) paradigm. Participants were asked to perform a tone discrimination task via a bimanual keypress response and a modified Stroop task via a vocal response serially as Task 1 and Task 2, respectively. In Task 2, a neutral word was added on half of the trials and no neutral word on the other half of the trials to observe the Stroop dilution effect. The amount of Stroop dilution, as well as the Stroop effect, was relatively constant across different stimulus-onset asynchronies (SOAs), which implies that Stroop dilution occurs due to the competition between a neutral word and a color word after a target color bar is selected to be processed further. These results indicate that focused attention plays an important role in the modulation of Stroop interference by the presence of a neutral word.

Does Self-Associating a Geometric Shape Immediately Cause Attentional Prioritization?

In many cognitive tasks, stimuli associated with one's self elicit faster responses than stimuli associated with others. This is true for familiar self-representations (e.g., one's own name), for new self-associated stimuli, and for combinations of both. The current research disentangles the potential of self- versus stranger-representations for familiar, new, and paired (familiar + new) stimuli to guide attention. In Study 1 (N = 34), responses to familiar and new self- versus other representations were tested in a dot-probe task with a short stimulus-onset asynchrony (SOA; 100 ms). Study 2 (N = 31) and Study 3 (N = 35) use a long SOA (1,000 ms) to test whether the findings are mirrored in inhibition of return (IOR). We observe significant performance differences for targets following self- versus stranger-associated stimuli (i.e., a cuing effect or IOR depending on the SOA length), yet only when familiar representations are present. This indicates that, under conditions of attentional competition between self- and stranger-representations, familiar self-representations impact the distribution of attention while new self-representations alone do not.

To stay or not to stay: The stability of choice perseveration in value-based decision making.

In real life, decisions are often naturally embedded in decision sequences. In contrast, in the laboratory, decisions are oftentimes analysed in isolation. Here, we investigated the influence of decision sequences in value-based decision making and whether the stability of such effects can be modulated. In our decision task, participants needed to collect rewards in a virtual two-dimensional world. We presented a series of two reward options that were either quick to collect but were smaller in value or took longer to collect but were larger in value. The subjective value of each option was driven by the options' value and how quickly they could be reached. We manipulated the subjective values of the options so that one option became gradually less valuable over the course of a sequence, which allowed us to measure choice perseveration (i.e., how long participants stick to this option). In two experiments, we further manipulated the time interval between two trials (inter-trial interval), and the time delay between the onsets of both reward options (stimulus onset asynchrony). We predicted how these manipulations would affect choice perseveration using a computational attractor model. Our results indicate that both the inter-trial interval and the stimulus onset asynchrony modulate choice perseveration as predicted by the model. We discuss how our findings extend to research on cognitive stability and flexibility.

The effect of eye disease, cataract surgery and hearing aid use on multisensory integration in ageing

Sensory impairment is common in ageing, as are approaches to treat it. However, the impact of age-related sensory impairment upon multisensory perception remains unexplored, despite the multisensory nature of our environment. Here, we used data from The Irish Longitudinal Study of Ageing (TILDA) to investigate whether common, age-related eye diseases (cataracts, glaucoma and Age-Related Macular Degeneration, ARMD) and clinical intervention to improve sensory function (cataract removal and hearing aids) influence multisensory integration in older adults. Integration was measured using the Sound-Induced Flash Illusion (SIFI), and the extent to which identifying two flashes was improved by accompanying auditory information (“visual gain”). Visual gain was not influenced by eye disease or treatment. For the SIFI, participants self-reporting cataracts, ARMD or glaucoma were as susceptible as healthy controls, even when controlling for age, sex, cognition, self-reported vision/hearing and visual acuity. In a second analysis using retinal photographs, glaucoma and ARMD (hard drusen) did not influence susceptibility relative to controls. However, participants with soft drusen ARMD were more susceptible to the illusion at long Stimulus-Onset Asynchronies (SOAs) compared with controls. Following this, we identified groups reporting bilateral cataract removal or hearing aid acquisition >4 years and <2 years prior to assessment, enabling comparison of longer- and shorter-term effects of interventions. Cataract removal groups did not differ from controls. Longer-term hearing aid users were less susceptible to the SIFI at short SOAs compared with controls. Our findings suggest that multisensory integration in ageing might be specifically influenced by ARMD (soft drusen) and hearing aid use.

Supramodal executive control of attention: Evidence from unimodal and crossmodal dual conflict effects

Although we have demonstrated that the executive control of attention acts supramodally as shown by significant correlation between conflict effect measures in visual and auditory tasks, no direct evidence of the equivalence in the computational mechanisms governing the allocation of executive control resources within and across modalities has been found. Here, in two independent groups of 40 participants each, we examined the interaction effect of conflict processing in both unimodal (visual) and crossmodal (visual and auditory) dual-conflict paradigms (flanker conflict processing in Task 1 and then in the following Task 2) with a manipulation of the stimulus onset asynchrony (SOA). In both the unimodal and the crossmodal dual-conflict paradigms, the conflict processing of Task 1 significantly interfered with the processing of Task 2 when the SOA was short, as shown by an additive interference effect of Task 1 on Task 2 under the time constraints. These results suggest that there is a unified supramodal entity that supports conflict processing by implementing comparable mechanisms in unimodal and crossmodal scenarios.

Impaired mechanism of visual focal attention in posterior cortical atrophy.

Objective: Simultanagnosia, a deficit in holistic visual perception, is among the most prominent features of posterior cortical atrophy (PCA). Deficits in visuoperceptual and attentional mechanisms could contribute to simultanagnosia. In the present study, we explored the impaired visual perception of global configuration with two main hypotheses: (a) It is due to a deficit in processing low-spatial frequency stimuli, and (b) it arises from deficits in adjusting attentional focus. Method: The visuoperceptual mechanism was explored by asking participants (5 PCA patients and 20 age- and education-matched healthy controls) to report the local and global elements of incongruent hierarchical letters. Stimuli were unbiased (black letters/white background) and parvocellular biased (red letters/green background). A cued T-detection task, where the stimulus onset asynchrony and the cues' features varied, was used to explore focal attention. Results: PCA patients systematically failed in reporting the global but not the local element. The parvocellular-biased condition partially improved the performance in only 1 patient. In the T-detection task, controls responded faster to targets cued by red dots and small cues as compared to no cues. Conversely, the cue's features did not affect patients' performance. Conclusions: Results only partially support the hypothesis according to which simultanagnosia is driven by an impairment in processing low-spatial frequencies. Data indicate a deficit in the flexibility of focal attention that prevents PCA patients from adapting the attentional window to the stimulus features. Simultanagnosia in PCA can be conceptualized as a complex result of a deficit involving visuoperceptual and exogenous attentional mechanisms. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Different temporal dynamics of object-based attentional allocation for reward and non-reward objects.

Previous studies have confirmed that both non-reward objects (such as rectangles) and reward objects (such as banknotes) can guide the allocation of our attention; however, it is unclear whether the allocation mode of attention for reward objects is the same as for non-reward objects. This study aims to evaluate different modes of object-based attentional selection elicited by two types of objects: reward objects and non-reward objects. In our analysis, we used a two-rectangle paradigm in which two objects were presented visually. In a series of four experiments, we found a constant object-based effect with non-reward objects, such as rectangles and umbrellas, as stimuli in all of the stimulus onset asynchrony (SOA) conditions (Experiments 1 and 4), but the object-based effect disappeared only at longer SOA with reward objects such as monetary and food objects as stimuli (Experiments 2 and 3). Moreover, we found that monetary and food objects induced similar object-based effects. These results suggest that the temporal dynamics of object-based attentional allocation are different with respect to reward and non-reward objects, and different types of reward objects can guide attentional allocation in a similar way.

Electrophysiological Dynamics of Visual-Tactile Temporal Order Perception in Early Deaf Adults.

Studies of compensatory plasticity in early deaf (ED) individuals have mainly focused on unisensory processing, and on spatial rather than temporal coding. However, precise discrimination of the temporal relationship between stimuli is imperative for successful perception of and interaction with the complex, multimodal environment. Although the properties of cross-modal temporal processing have been extensively studied in neurotypical populations, remarkably little is known about how the loss of one sense impacts the integrity of temporal interactions among the remaining senses. To understand how auditory deprivation affects multisensory temporal interactions, ED and age-matched normal hearing (NH) controls performed a visual-tactile temporal order judgment task in which visual and tactile stimuli were separated by varying stimulus onset asynchronies (SOAs) and subjects had to discern the leading stimulus. Participants performed the task while EEG data were recorded. Group averaged event-related potential waveforms were compared between groups in occipital and fronto-central electrodes. Despite similar temporal order sensitivities and performance accuracy, ED had larger visual P100 amplitudes for all SOA levels and larger tactile N140 amplitudes for the shortest asynchronous (± 30 ms) and synchronous SOA levels. The enhanced signal strength reflected in these components from ED adults are discussed in terms of compensatory recruitment of cortical areas for visual-tactile processing. In addition, ED adults had similar tactile P200 amplitudes as NH but longer P200 latencies suggesting reduced efficiency in later processing of tactile information. Overall, these results suggest that greater responses by ED for early processing of visual and tactile signals are likely critical for maintained performance in visual-tactile temporal order discrimination.

Examining the Temporal Limits of Enhanced Visual Feature Detection in Children With Autism.

The enhanced perceptual processing of visual features in children with autism spectrum disorder (ASD) is supported by an abundance of evidence in the spatial domain, with less robust evidence regarding whether this extends to information presented across time. The current study aimed to replicate and extend previous work finding that children with an ASD demonstrated enhanced perceptual accuracy in detecting feature-based (but not categorically defined) targets in time, when these were presented quickly, at a stimulus onset asynchrony (SOA) of 50 ms per item. Specifically, we extend the range of SOAs to examine the temporal boundaries of this enhanced accuracy and examine whether there is a relationship between ASD-related traits and detection accuracy on temporal visual search tasks. Individuals with autism perceived feature-based targets with statistically higher accuracy than their typically developing peers between SOAs of 39 and 65 ms and were numerically faster at all SOAs. No group differences were noted for category-based task accuracy. Our results also demonstrated that ASD-related traits measured by the autism spectrum quotient were positively correlated with accuracy on the feature-based task. Overall, results suggest that accurate visual perception of features (particularly color) is enhanced in children with ASD across time. LAY SUMMARY: Our results suggest that children with autism are able to process visual features, such as color, more accurately than typically developing children, even when these are presented very rapidly. Accuracy was higher in children with higher levels of autism-related traits and symptoms. Our findings suggest that more accurate visual perception exists not only across space in children with autism, as much of the existing literature demonstrates, but also over time. Autism Res 2020, 13: 1561-1572. © 2020 International Society for Autism Research, Wiley Periodicals, Inc.

Age-Related Changes in Audiovisual Simultaneity Perception and Their Relationship With Working Memory.

Perceiving simultaneity of a visual and an auditory signal is critical for humans to integrate these multisensory inputs effectively and respond properly. We examined age-related changes in audiovisual simultaneity perception, and the relationships between this perception and working memory performances with aging. Audiovisual simultaneity perception of young, middle-aged, and older adults was measured using a simultaneity judgment (SJ) task, in which a flash and a beep were presented at 1 of 11 stimulus-onset asynchronies (SOAs). Participants judged whether these two stimuli were perceived simultaneously. Precision of simultaneity perception, the SOA corresponding to the point of subjective simultaneity (PSS), and response errors at each SOA were estimated using model fitting. The precision and PSS are associated with multisensory perception per se, whereas the response error reflects executive ability when performing the SJ task. Visual working memory of the same middle-aged and older adults was measured using the Cambridge Neuropsychological Test Automated Battery (CANTAB) beforehand. Compared to young adults' performances, middle-aged and older adults showed a decreased precision, a shift of PSS toward the visual-leading SOAs, and increased response errors at the visual-leading SOAs. Among these changes, only the increased response errors correlated with worse spatial recognition memory in middle-aged and older adults. Age-related decrements in audiovisual simultaneity perception start from middle age and are manifested in both perceptual and executive parameters. Furthermore, higher-order executive ability is plausibly a common cause for age-related degenerations in the audiovisual simultaneity perception and visual working memory.

Perceived and one’s own motion in response priming

AbstractIn response priming, motor pre-activations from a prime to the response to a target can be measured, as a function of whether they require the same (compatible) or different (incompatible) responses. With moving primes and static arrow targets, the results depend on the stimulus onset asynchrony between prime and target: with short SOAs, there were faster responses to compatible than incompatible targets, with longer SOAs, the pattern reverses. However, this reversal was not found with more biological motions. The current study comprised 3 experiments in order to replicate several findings from previous research and add evidence regarding the interplay of one’s own and perceived motions. Subjects performed a response priming task with moving prime stimuli while in motion themselves. With this paradigm, we tested the general influence of motion on responding and compatibility effects in response priming with moving prime stimuli. Furthermore, we assessed specific interactions of features of the perceived stimuli (e.g., moving vs. static; direction of the prime or target) and the own motion (e.g., walking vs. standing; direction of being rotated). We used two different own motions (walking on a treadmill, Exp. 1 &amp; 3; rotating in a human gyroscope, Exp. 2) and two different visual stimulus types (rows-of-dots, Exp. 1 &amp; 2; point light displays, Exp. 3). Compatibility effects were, in general, neither increased nor decreased during motion. Their size depended on the stimulus type, the velocity of one’s own motion, and several interactions of perceived and own motion. We discuss our findings with respect to perception-action interactions and previous findings on response priming with moving prime stimuli.