Stimulus Onset Asynchrony Research Articles

Developmental changes in the perception of audiotactile simultaneity

We charted the developmental trajectory of the perception of audiotactile simultaneity by testing three groups of children (aged 7, 9, and 11 years) and one group of adults. A white noise burst and a tap to the index finger were presented at 1 of 13 stimulus onset asynchronies (SOAs), and the participants were asked to report whether the two stimuli were simultaneous. Compared with adults, 7-year-olds made significantly more simultaneous responses at 9 of the 13 SOAs, whereas 9-year-olds differed from adults at only 2 SOAs. The precision of simultaneity perception was lower, and response errors were higher, in younger children than in adults. The 11-year-olds were adult-like on all measures, thereby demonstrating that judgments about simultaneity for audiotactile stimuli are mature by 11 years. This developmental pattern is similar to that for simultaneity perception for visuotactile stimuli but later than that for audiovisual stimuli. The longer developmental trajectories of the perception of simultaneity between touch and vision and between touch and audition may arise from the need to coordinate and recalibrate between different reference frames and different neural transmission times in each sensory system during body growth; in addition, the ubiquity of audiovisual experience in everyday life may accelerate the development of that modality pairing.

Olfactory Object Recognition Based on Fine-Scale Stimulus Timing in Drosophila

SummaryOdorants of behaviorally relevant objects (e.g., food sources) intermingle with those from other sources. Therefore to determine whether an odor source is good or bad—without actually visiting it—animals first need to segregate the odorants from different sources. To do so, animals could use temporal stimulus cues, because odorants from one source exhibit correlated fluctuations, whereas odorants from different sources are less correlated. However, the behaviorally relevant timescales of temporal stimulus cues for odor source segregation remain unclear. Using behavioral experiments with free-flying flies, we show that (1) odorant onset asynchrony increases flies' attraction to a mixture of two odorants with opposing innate or learned valence and (2) attraction does not increase when the attractive odorant arrives first. These data suggest that flies can use stimulus onset asynchrony for odor source segregation and imply temporally precise neural mechanisms for encoding odors and for segregating them into distinct objects.

The time course of distractor-based response activation with predictable and unpredictable target onset.

Electrophysiological recording in a temporal flanker task (i.e., distractors preceding the targets) has demonstrated that distractor processing is adjusted to the overall utility of the distractors. Under high utility, that is, distractors are predictive of the target/response, distractors immediately activate the corresponding response (as indicated by the lateralized readiness potential, LRP). This activation has been shown to be markedly postponed when the target predictably occurs delayed. To investigate the occurrence and time course of distractor-related response activation under conditions of unpredictable target onset, we randomly varied the stimulus-onset asynchrony (SOA) between distractors and targets and recorded the distractor-evoked LRP. When the distractor utility was high, an LRP occurred shortly after distractor presentation. In case of a long SOA the time course of this LRP was characterized by a drop back to baseline and a subsequent re-activation that reached a substantial level before target onset. These results suggest that distractor processing is characterized by sophisticated adjustments to experienced utility and temporal constraints of the task as well as by further control processes that regulate premature response activation.

Lateralized Affective Word Priming and Gender Effect.

Affective priming research suggests that processing of affective words is a quick and short lived process. Using the divided visual field (DVF) paradigm, investigations of the lateralization of affective word processing have yielded inconsistent results. However, research on semantic processing of words generally suggests that the left hemisphere (LH) is the location where rapid processing occurs. We investigated the processing of affective (emotional) words using a combination of the DVF and affective priming paradigms, and four stimulus onset asynchronies (SOAs)—0, 150, 300, and 750 ms. The priming pattern yielded by males (n = 32) showed quick priming (at 0-ms SOA) of affective words in the LH; there was slower right hemisphere (RH) priming of affective words (at 750-ms SOA). In females (n = 28), both hemispheres were associated with quick priming of affective words (at 300-ms SOA in the LH and at 150-ms SOA in the RH). Results demonstrate the capability of both cerebral hemispheres in the processing of words with affective meaning, along with leading role of the left hemisphere in this process. This is similar to the results of semantic research that suggest access to word meanings occurs in both hemispheres, but different mechanisms might be involved. While the LH seems to prime affective words quickly regardless of gender, gender differences are likely in the RH in that affective word processing probably occurs slowly in males but rapidly in females. This gender difference may result from increased sensitivity to the emotional feature of affective words in females.

Improve P300 Speller Performance by Changing Stimulus Onset Asynchrony (SOA) Without Retraining the Subject-Independent Model

P300 speller is a famous brain-computer interface (BCI) method, which translates mental attention by identifying the event-related potentials evoked by target stimulus. To improve its efficiency, subject-independent classification models and dynamical stopping strategies have been introduced into P300 speller. However, it has still not been determined whether these methods remain effective when the configurations of visual stimuli are changed. This study investigates whether subject-independent dynamical stopping model (SIDSM) can maintain high efficiency in the case of stimulus onset asynchrony (SOA) change. The SIDSM was built on a 55-subject database, and the classification efficiency was tested online with 14 new subjects. During the online experiment, four SOA conditions were tested, one of which had the same SOA as the modeling data, while the other three had different SOA settings. The SIDSM obtained comparable classification accuracy under different SOA settings. Thus, the efficiency of information transmission can be significantly improved by changing SOA only, without retraining the model. These results suggest that SIDSM has good robustness to changes in stimulus settings and can provide P300 speller with good flexibility for individual optimization.

Age Related Changes in Attentional Bias Triggered by Gaze Cues

We investigated if attentional bias directed to the right increased with age. We assessed the characteristics of the following types of eye-gaze by using the Posner cueing paradigm. Younger (n =16) and older (n = 20) adults participated in this study. First of all, a face which looked straight ahead was presented at the center of screen, followed by a gaze cue that looked left or right. Immediately after this informative cue, a target stimulus (“*”) appeared to the left or right of the face. The stimulus-onset asynchrony (SOA) between the cue and the target was selected from 300, 700, and 1100 ms. Participants were required to judge whether the target appeared to the left or the right of the gaze cue as quickly and accurately as possible. Results showed that older adults indicate a larger positive gaze-cueing effect when the eye-gaze shifted rightward, whereas this effect was not observed for a leftward shift. Moreover, a negative gaze-cueing effect (inhibition of return) was observed when the SOA was longer only for the leftward eye-gaze shift of older adults. These modulations of the cueing effect did not appear in younger adults. These findings demonstrate that the rightward attentional bias in older adults is more robust than the leftward bias.

Trunk rotation and handedness modulate cortical activation in neglect-associated regions during temporal order judgments.

The rotation of the trunk around its vertical midline could be shown to bias visuospatial temporal judgments towards targets in the hemifield ipsilateral to the trunk orientation and to improve visuospatial performance in patients with visual neglect. However, the underlying brain mechanisms are not well understood. Therefore, the goal of the present study was to investigate the neural effects associated with egocentric midplane shifts under consideration of individual handedness. We employed a visuospatial temporal order judgment (TOJ) task in healthy right- and left-handed subjects while their trunk rotation was varied. Participants responded by a saccade towards the stimulus perceived first out of two stimuli presented with different stimulus onset asynchronies (SOA). Apart from gaze behavior, BOLD-fMRI responses were measured using functional magnetic resonance imaging (fMRI). Based on findings from spatial neglect research, analyses of fMRI-BOLD responses were focused on a bilateral fronto-temporo-parietal network comprising Brodmann areas 22, 39, 40, and 44, as well as the basal ganglia core nuclei (caudate, putamen, pallidum).We observed an acceleration of saccadic speed towards stimuli ipsilateral to the trunk orientation modulated by individual handedness. Left-handed participants showed the strongest behavioral and neural effects, suggesting greater susceptibility to manipulations of trunk orientation. With respect to the dominant hand, a rotation around the vertical trunk midline modulated the activation of an ipsilateral network comprising fronto-temporo-parietal regions and the putamen with the strongest effects for saccades towards the hemifield opposite to the dominant hand. Within the investigated network, the temporo-parietal junction (TPJ) appears to serve as a region integrating sensory, motor, and trunk position information.Our results are discussed in the context of gain modulatory and laterality effects.

Cognitive control in the cocktail party: Preparing selective attention to dichotically presented voices supports distractor suppression.

The goal of the present study was to investigate preparatory mechanisms of auditory selective attention. In two experiments, participants performed a classification task on one of two dichotically presented spoken number words, one spoken by a female, one spoken by a male. A cue indicated which gender participants had to attend to in the upcoming trial, so that attention switches and repetitions occurred randomly. The cue-target interval (CTI) was either 400 ms or 1,200 ms. Stimulus onset asynchrony (SOA) between target and distractor word varied; hence, the distractor could be presented before or after the target. In two experiments, we found robust performance costs of attention switches. Like in previous studies using versions of this paradigm, these switch costs were not significantly reduced by prolonged CTI, even though we found substantial general cue-based preparation effects. The most important finding refers to the influence of SOA, showing that the general preparation effect was greater in the condition with the distractor presented first than in the condition with the target presented first. Thus, increased time to prepare for the attention focus of the upcoming trials seems to benefit distractor suppression more than target enhancement. This occurred in switch trials and repetition trials alike, suggesting that it is a general feature of auditory attention.

Temporal window of integration estimated by omission in bone-conducted ultrasound

Bone-conducted ultrasound (BCU) can be heard for both normal-hearing and some profoundly deaf individuals. Moreover, amplitude-modulated BCU can transmit the speech signal. These characteristics of BCU provide the possibility of the developing a bone-conducted ultrasonic hearing aid. Previous studies on the perception mechanism of speech-modulated BCU have pointed to the importance of temporal rather than frequency information. In order to elucidate the perception of speech-modulated BCU, further investigation is need concerning the processing of temporal information. The temporal processing of air-conducted audible sounds (ACASs) involves the integration of closely presented sounds into a single information unit. The long-temporal window of integration was estimated approximately 150–200 ms, which contribute to the discrimination of speech sound. The present study investigated the long-temporal integration system for BCU evaluated by stimulus omission using magnetoencephalography.Eight participants with normal hearing took part in this study. Ultrasonic tone burst with the duration of 50 ms and frequency of 30 kHz was used as the standard stimulus and presented with steady onset-to-onset times or stimulus-onset asynchronies (SOAs). In each sequence, the duration of the SOAs were set to 100, 125, 150, 175, 200, or 350 ms. For deviant, tones were randomly omitted from the stimulus train. Definite mismatch fields were elicited by sound omission in the stimulus train with an SOA of 100–150 ms, but weren’t with an SOA of 200 and 350 ms for all participants.We found that stimulus train for BCUs can be integrated within a temporal window of integration with an SOA of 100–150 ms, but are regarded as a separate event when the SOA is 200 or 350 ms in duration. Therefore, we demonstrated that the long-temporal window of integration for BCUs estimated by omission was 150–200 ms, which was similar to that for ACAS (Yabe et al. NeuroReport 8 (1997) 1971–1974 and Psychophysiology. 35 (1998) 615–619). These findings contribute to the elucidation and improvement of the perception of speech-modulated BCU.

Human-like perceptual masking is difficult to observe in rats performing an orientation discrimination task.

Visual masking occurs when the perception of a brief target stimulus is affected by a preceding or succeeding mask. The uncoupling of the target and its perception allows an opportunity to investigate the neuronal mechanisms involved in sensory representation and visual perception. To determine whether rats are a suitable model for subsequent studies of the neuronal basis of visual masking, we first demonstrated that decoding of neuronal responses recorded in the primary visual cortex (V1) of anaesthetized rats predicted that orientation discrimination performance should decline when masking stimuli are presented immediately before or after oriented target stimuli. We then trained Long-Evans rats (n = 7) to discriminate between horizontal and vertical target Gabors or gratings. In some trials, a plaid mask was presented at varying stimulus onset asynchronies (SOAs) relative to the target. Spatially, the masks were presented either overlapping or surrounding the target location. In the absence of a mask, all animals could reliably discriminate orientation when stimulus durations were 16 ms or longer. In the presence of a mask, discrimination performance was impaired, but did not systematically vary with SOA as is typical of visual masking. In humans performing a similar task, we found visual masking impaired perception of the target at short SOAs regardless of the spatial or temporal configuration of stimuli. Our findings indicate that visual masking may be difficult to observe in rats as the stimulus parameters necessary to quantify masking will make the task so difficult that it prevents robust measurement of psychophysical performance. Thus, our results suggest that rats may not be an ideal model to investigate the effects of visual masking on perception.

Depression symptomatology correlates with event-related potentials in Parkinson's disease: An affective priming study

BackgroundDepression is a predominant non-motor symptom of Parkinson's disease (PD), which is often under recognised and undertreated. To improve identification of depression in PD it is imperative to examine objective brain-related markers. The present study addresses this gap by using electroencephalography (EEG) to evaluate the processing of emotionally valanced words in PD. MethodsFifty non-demented PD patients, unmedicated for depression or anxiety, completed an affective priming task while EEG was simultaneously recorded. Prime and target word pairs of negative or neutral valence were presented at a short 250 ms stimulus onset asynchrony. Participants were asked to evaluate the valence of the target word by button press. Depression was measured using an established rating scale. Repeated measures analysis of covariance and correlational analyses were performed to examine whether event-related potentials (ERP) varied as a function of depression scores. ResultsKey ERP findings reveal reduced responses in parietal midline P300, N400 and Late Positive Potential (LPP) difference waves between congruent and incongruent neutral targets in patients with higher depression scores. LimitationsComparisons of ERPs were limited by insufficient classification of participants with and without clinical depression. A majority of PD patients who had high depression scores were excluded from the analysis as they were receiving antidepressant and/or anxiolytic medications which could interfere with ERP sensitivity. ConclusionsThe present study suggests that the Pz-P300, N400 and LPP are ERP markers relates to emotional dysfunction in PD. These findings thus advance current knowledge regarding the neurophysiological markers of a common neuropsychiatric deficit in PD.

Mechanisms underlying auditory and cross-modal emotional attentional biases: Engagement with and disengagement from aversive auditory stimuli

There has been no consistent conclusion concerning whether auditory spatial attention or visual spatial attention could be modulated by auditory aversive cues. In three experiments, we used direct aversive auditory stimuli (white noise) as cues and explored which subcomponents of attentional bias contribute to auditory and cross-modal spatial attention in unselected samples. In Experiment 1, in a dot-probe paradigm, we adopted auditory stimuli (aversive or neutral) as cues and a tick sound as target, and we set two stimulus onset asynchrony (SOA) conditions: 150 ms and 500 ms. The results of experiment 1 showed that participants performed faster on congruent trials than on incongruent trials and participants exhibited an auditory emotional attentional bias to aversive auditory stimuli in 150 ms SOA condition. Subsequently, in experiment 2 and experiment 3, we employed an auditory emotional spatial cueing task using neutral and negative auditory stimuli as cues. Targets were auditory stimuli (Experiment 2) or visual stimuli (Experiment 3). The results of experiment 2 showed that participants performed faster to targets primed by negative cues than to those primed by neutral cues in valid condition; and performed slower to targets primed by negative cues than to those primed by neutral cues in invalid condition in 150 ms SOA condition. Experiment 2 revealed that speeded engagement with and delayed disengagement from aversive auditory stimuli were both present at a 150 ms SOA condition; at 500 ms SOA condition, only the former effect was present, and auditory inhibition of return was also observed. Experiment 3 produced similar results cross-modally, but cross-modal inhibition of return was not observed. In all experiments, we conclude that emotional attention can operate within the auditory modality and across sensory modalities, and that both engagement and disengagement bias contribute to auditory and cross-modal emotional attention.

Temporal Generalization of Synchronized Saccades Beyond the Trained Range in Monkeys.

Synchronized movements with external periodic rhythms, such as dancing to a beat, are commonly observed in daily life. Although it has been well established that some vocal learning species (including parrots and humans) spontaneously develop this ability, it has only recently been shown that monkeys are also capable of predictive and tempo-flexible synchronization to periodic stimuli. In our previous study, monkeys were trained to make predictive saccades for alternately presented visual stimuli at fixed stimulus onset asynchronies (SOAs) to obtain a liquid reward. The monkeys generalized predictive synchronization to novel SOAs in the middle of trained range, suggesting a capacity for tempo-flexible synchronization. However, it is possible that when encountering a novel tempo, the monkeys might sample learned saccade sequences from those for the short and long SOAs so that the mean saccade interval matched the untrained SOA. To eliminate this possibility, in the current study we tested monkeys on novel SOAs outside the trained range. Animals were trained to generate synchronized eye movements for 600 and 900-ms SOAs for a few weeks, and then were tested for longer SOAs. The accuracy and precision of predictive saccades for one untrained SOA (1200 ms) were comparable to those for the trained conditions. On the other hand, the variance of predictive saccade latency and the proportion of reactive saccades increased significantly in the longer SOA conditions (1800 and 2400 ms), indicating that temporal prediction of periodic stimuli was difficult in this range, similar to previous results on synchronized tapping in humans. Our results suggest that monkeys might share similar synchronization mechanisms with humans, which can be subject to physiological examination in future studies.

Dual-Tasking in the Near-Hand Space: Effects of Stimulus-Hand Proximity on Between-Task Shifts in the Psychological Refractory Period Paradigm.

Two decades of research indicate that visual processing is typically enhanced for items that are in the space near the hands (near-hand space). Enhanced attention and cognitive control have been thought to be responsible for the observed effects, amongst others. As accumulating experimental evidence and recent theories of dual-tasking suggest an involvement of cognitive control and attentional processes during dual tasking, dual-task performance may be modulated in the near-hand space. Therefore, we performed a series of three experiments that aimed to test if the near-hand space affects the shift between task-component processing in two visual-manual tasks. We applied a Psychological Refractory Period Paradigm (PRP) with varying stimulus-onset asynchrony (SOA) and manipulated stimulus-hand proximity by placing hands either on the side of a computer screen (near-hand condition) or on the lap (far-hand condition). In Experiment 1, Task 1 was a number categorization task (odd vs. even) and Task 2 was a letter categorization task (vowel vs. consonant). Stimulus presentation was spatially segregated with Stimulus 1 presented on the right side of the screen, appearing first and then Stimulus 2, presented on the left side of the screen, appearing second. In Experiment 2, we replaced Task 2 with a color categorization task (orange vs. blue). In Experiment 3, Stimulus 1 and Stimulus 2 were centrally presented as a single bivalent stimulus. The classic PRP effect was shown in all three experiments, with Task 2 performance declining at short SOA while Task 1 performance being relatively unaffected by task-overlap. In none of the three experiments did stimulus-hand proximity affect the size of the PRP effect. Our results indicate that the switching operation between two tasks in the PRP paradigm is neither optimized nor disturbed by being processed in near-hand space.

Impaired Tactile Temporal Discrimination in Patients With Hepatic Encephalopathy.

The sensory system constantly receives stimuli from the external world. To discriminate two stimuli correctly as two temporally distinct events, the temporal distance or stimulus onset asynchrony (SOA) between the two stimuli has to exceed a specific threshold. If the SOA between two stimuli is shorter than this specific threshold, the two stimuli will be perceptually fused and perceived as one single stimulus. Patients with hepatic encephalopathy (HE) are known to show manifold perceptual impairments, including slowed visual temporal discrimination abilities as measured by the critical flicker frequency (CFF). Here, we hypothesized that HE patients are also impaired in their tactile temporal discrimination abilities and, thus, require a longer SOA between two tactile stimuli to perceive the stimuli as two temporally distinct events. To test this hypothesis, patients with varying grades of HE and age-matched healthy individuals performed a tactile temporal discrimination task. All participants received two tactile stimuli with varying SOA applied to their left index finger and reported how many distinct stimuli they perceived (“1” vs. “2”). HE patients needed a significantly longer SOA (138.0 ± 11.3 ms) between two tactile stimuli to perceive the stimuli as two temporally distinct events than healthy controls (78.6 ± 13.1 ms; p < 0.01). In addition, we found that the temporal discrimination ability in the tactile modality correlated positively with the temporal discrimination ability in the visual domain across all participants (i.e., negative correlation between tactile SOA and visual CFF: r = −0.37, p = 0.033). Our findings provide evidence that temporal tactile perception is substantially impaired in HE patients. In addition, the results suggest that tactile and visual discrimination abilities are affected in HE in parallel. This finding might argue for a common underlying pathophysiological mechanism. We argue that the known global slowing of neuronal oscillations in HE might represent such a common mechanism.

V1 activity during feedforward and early feedback processing is necessary for both conscious and unconscious motion perception

The study of blindsight has revealed a seminal dissociation between conscious vision and visually guided behavior: some patients who are blind due to V1 lesions seem to be able to employ unconscious visual information in their behavior. The standard assumption is that these findings generalize to the neurologically healthy. We tested whether unconscious processing of motion is possible without the contribution of V1 in neurologically healthy participants by disturbing activity in V1 using transcranial magnetic stimulation (TMS). Unconscious processing was measured with redundant target effect (RTE), a phenomenon where participants respond faster to two stimuli than to one stimulus, when the task is just to respond as fast as possible when one stimulus or two simultaneous stimuli are presented. We measured the RTE caused by a motion stimulus. V1 activity was interfered with different stimulus onset asynchronies (SOA) to test whether TMS delivered in a specific time window suppresses conscious perception (participant reports seeing only one of the two stimuli) but does not affect unconscious processing (RTE). We observed that at each SOA, when TMS suppressed conscious perception of the stimulus, the RTE was also eliminated. However, when visibility of the redundant target was suppressed with a visual mask, we found unconscious processing of motion. This suggests that unconscious processing of motion depends on V1 in neurologically healthy humans. We conclude that the neural mechanisms that enable motion processing in blindsight are modulated by neuroplastic changes in connectivity between subcortical areas and the visual cortex after the V1 lesion. Neurologically healthy observers cannot process motion unconsciously without functioning of V1.

Laser Evoked potentials: a pain related signal beyond the stimulus salience

Sensitivity to the temporal relationship between auditory and visual stimuli is key to efficient audiovisual integration. However, even adults vary greatly in their ability to detect audiovisual temporal asynchrony. What underlies this variability is currently unknown. We recorded event-related potentials (ERPs) while participants performed a simultaneity judgment task on a range of audiovisual (AV) and visual-auditory (VA) stimulus onset asynchronies (SOAs) and compared ERP responses in good and poor performers to the 200 ms SOA, which showed the largest individual variability in the number of synchronous perceptions. Analysis of ERPs to the VA200 stimulus yielded no significant results. However, those individuals who were more sensitive to the AV200 SOA had significantly more positive voltage between 210 and 270 ms following the sound onset. In a follow-up analysis, we showed that the mean voltage within this window predicted approximately 36% of variability in sensitivity to AV temporal asynchrony in a larger group of participants. The relationship between the ERP measure in the 210–270 ms window and accuracy on the simultaneity judgment task also held for two other AV SOAs with significant individual variability −100 and 300 ms. Because the identified window was time-locked to the onset of sound in the AV stimulus, we conclude that sensitivity to AV temporal asynchrony is shaped to a large extent by the efficiency in the neural encoding of sound onsets.

Audiovisual semantic interactions between linguistic and nonlinguistic stimuli: The time-courses and categorical specificity.

We examined the time-courses and categorical specificity of the crossmodal semantic congruency effects elicited by naturalistic sounds and spoken words on the processing of visual pictures (Experiment 1) and printed words (Experiment 2). Auditory cues were presented at 7 different stimulus onset asynchronies (SOAs) with respect to the visual targets, and participants made speeded categorization judgments (living vs. nonliving). Three common effects were observed across 2 experiments: Both naturalistic sounds and spoken words induced a slowly emerging congruency effect when leading by 250 ms or more in the congruent compared with the incongruent condition, and a rapidly emerging inhibitory effect when leading by 250 ms or less in the incongruent condition as opposed to the noise condition. Only spoken words that did not match the visual targets elicited an additional inhibitory effect when leading by 100 ms or when presented simultaneously. Compared with nonlinguistic stimuli, the crossmodal congruency effects associated with linguistic stimuli occurred over a wider range of SOAs and occurred at a more specific level of the category hierarchy (i.e., the basic level) than was required by the task. A comprehensive framework is proposed to provide a dynamic view regarding how meaning is extracted during the processing of visual or auditory linguistic and nonlinguistic stimuli, therefore contributing to our understanding of multisensory semantic processing in humans. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Common Cognitive Control Processes Underlying Performance in Task-Switching and Dual-Task Contexts.

In the present study, participants performed highly comparable task-switching and dual-task paradigms, and the paradigm-specific performance costs were analysed in the context of the commonly postulated core components of cognitive control (i.e., working memory updating, inhibition, and shifting). In the task-switching paradigm, we found switch costs (i.e., switch trials vs. repetition trials) and mixing costs (i.e., repetition trials in mixed-task blocks vs. single-task trials). In the dual-task paradigm, we observed a psychological refractory period (PRP) effect (i.e., Task 2 [T2] performance after short stimulus-onset asynchrony [SOA] vs. long SOA), dual-task costs (i.e., T2 dual-task performance with a long SOA in trials with a task repetition between Task 1 [T1] and T2 vs. single-task performance), and switch costs in T2 (i.e., dual-task performance in trials with a switch between T1 and T2 vs. dual-task performance in trials with a repetition between T1 and T2). A within-subjects comparison of the performance costs showed a correlation between mixing costs and dual-task costs, possibly indicating shared underlying cognitive control processes in terms of working memory updating. Surprisingly, there was also a correlation between switch costs and the PRP effect, presumably suggesting that cognitive control, as opposed to passive queuing of response selection processes, contributes to the PRP effect.

The influence of phasic alerting on multisensory temporal precision

The relationship between attention and multisensory integration has attracted the attention of many researchers but remains a topic of debate. As a mechanism that regulates the intensity of attention, little is known regarding whether and how phasic alerting affects multisensory perception. Three experiments and warning cues were employed to investigate the influence of phasic alerting on multisensory temporal processing. Experiments 1 and 2 used a temporal order judgement task and a simultaneity judgement task with audiovisual target stimuli presented at varying stimulus onset asynchronies. Experiment 3 further adopted a dual task to generate a new estimate of participants' performance. Although these tasks differ in terms of the required cognitive mechanisms, decreased just noticeable difference scores in trials with warning cues consistently indicated that participants under phasic alerting had enhanced multisensory temporal precision. The point of subjective simultaneity values differed among the three tasks, suggesting that the influence of phasic alerting on perceptual deviation might be modulated by specific task demands. Experiment 4 adopted a strict method to verify that the mechanisms by which warning cues facilitate multisensory temporal precision are most likely transient general arousal rather than temporal expectancy. There is a close relationship between multisensory integration and some neurodevelopmental disorders. Considering that phasic alerting may heighten attentional capacity, future research could explore the potential medical interventions for the patients with relatively limited attention resources.