Stimulus Presentation Research Articles

A user-friendly visual brain-computer interface based on high-frequency steady-state visual evoked fields recorded by OPM-MEG

Objective. Magnetoencephalography (MEG) shares a comparable time resolution with electroencephalography. However, MEG excels in spatial resolution, enabling it to capture even the subtlest and weakest brain signals for brain-computer interfaces (BCIs). Leveraging MEG’s capabilities, specifically with optically pumped magnetometers (OPM-MEG), proves to be a promising avenue for advancing MEG-BCIs, owing to its exceptional sensitivity and portability. This study harnesses the power of high-frequency steady-state visual evoked fields (SSVEFs) to build an MEG-BCI system that is flickering-imperceptible, user-friendly, and highly accurate. Approach. We have constructed a nine-command BCI that operates on high-frequency SSVEF (58–62 Hz with a 0.5 Hz interval) stimulation. We achieved this by placing the light source inside and outside the magnetic shielding room, ensuring compliance with non-magnetic and visual stimulus presentation requirements. Five participants took part in offline experiments, during which we collected six-channel multi-dimensional MEG signals along both the vertical (Z-axis) and tangential (Y-axis) components. Our approach leveraged the ensemble task-related component analysis algorithm for SSVEF identification and system performance evaluation. Main Results. The offline average accuracy of our proposed system reached an impressive 92.98% when considering multi-dimensional conjoint analysis using data from both the Z and Y axes. Our method achieved a theoretical average information transfer rate (ITR) of 58.36 bits min−1 with a data length of 0.7 s, and the highest individual ITR reached an impressive 63.75 bits min−1. Significance. This study marks the first exploration of high-frequency SSVEF-BCI based on OPM-MEG. These results underscore the potential and feasibility of MEG in detecting subtle brain signals, offering both theoretical insights and practical value in advancing the development and application of MEG in BCI systems.

Revisiting perceptual sensitivity to non-native speech in a diverse sample of bilinguals

Werker and Tees (1984) prompted decades of research attempting to detail the paths infants take towards specialisation for the sounds of their native language(s). Most of this research has examined the trajectories of monolingual children. However, it has also been proposed that bilinguals, who are exposed to greater phonetic variability than monolinguals and must learn the rules of two languages, may remain perceptually open to non-native language sounds later into life than monolinguals. Using a visual habituation paradigm, the current study tests this question by comparing 15- to 18-month-old monolingual and bilingual children’s developmental trajectories for non-native phonetic consonant contrast discrimination. A novel approach to the integration of stimulus presentation software with eye-tracking software was validated for objective measurement of infant looking time. The results did not support the hypothesis of a protracted period of sensitivity to non-native phonetic contrasts in bilingual compared to monolingual infants. Implications for diversification of perceptual narrowing research and implementation of increasingly sensitive measures are discussed.

Dissociable neuronal mechanism for different crossmodal correspondence effects in humans.

Crossmodal correspondences (CMCs) refer to associations between seemingly arbitrary stimulus features in different sensory modalities. Pitch‑size correspondences refer to the strong association of e.g., small objects with high pitches. Pitch‑elevation correspondences refer to the strong association of e.g., visuospatial elevated objects with high pitches. We used functional magnetic resonance imaging (fMRI) to study the neural components, which underlie the CMCs in pitch‑size and spatial pitch‑elevation. This study focuses on answering the question of whether or not different CMCs are driven by similar neural mechanisms. The comparison of congruent against incongruent trials allows the estimation of CMC effects across different CMCs. The analysis of the measured neural activity in different CMCs strongly pointed toward different mechanisms which are involved in the processing of pitch‑size and pitch‑elevation correspondences. Differential, whole brain effects were observed within the superior parietal lobule (SPL), cerebellum and Heschls' gyrus (HG). Further, the angular gyrus (AnG), the intraparietal sulcus (IPS) and anterior cingulate cortex (ACC) were engaged in processing the CMCs but showed different effects for processing congruent compared to incongruent stimulus presentations. Within pitch‑size significant effects in the AnG and ACC were found for congruent stimulus presentations whereas for pitch‑elevation, significant effects in the ACC and IPS were found for incongruent stimulus presentations. In summary, the present results indicated differential neural processing in different simple audio‑visual CMCs.

Stimulus-related modulation in the 1/f spectral slope suggests an impaired inhibition during a working memory task in people with multiple sclerosis

Background: An imbalance of excitatory and inhibitory synaptic transmission in multiple sclerosis (MS) may lead to cognitive impairment, such as impaired working memory. The 1/f slope of electroencephalography/magnetoencephalography (EEG/MEG) power spectra is shown to be a non-invasive proxy of excitation/inhibition balance. A flatter slope is associated with higher excitation/lower inhibition. Objectives: To assess the 1/f slope modulation induced by stimulus and its association with behavioral and cognitive measures. Methods: We analyzed MEG recordings of 38 healthy controls (HCs) and 79 people with multiple sclerosis (pwMS) while performing an n-back task including target and distractor stimuli. Target trials require an answer, while distractor trials do not. We computed the 1/f spectral slope through the fitting oscillations and one over f (FOOOF) algorithm within the time windows 1 second before and after each stimulus presentation. Results: We observed a flatter 1/f slope after distractor stimuli in pwMS compared to HCs. The 1/f slope was significantly steeper after stimulus for both HCs and pwMS and was significantly correlated with reaction times. This modulation in 1/f slope was significantly correlated with visuospatial memory assessed by the BVMT-R test. Conclusion: Our results suggest possible inhibitory mechanism deficits in pwMS during a working memory task.

Threat-dependent scaling of prelimbic dynamics to enhance fear representation

Promptly identifying threatening stimuli is crucial for survival. Freezing is a natural behavior displayed by rodents toward potential or actual threats. Although it is known that the prelimbic cortex (PL) is involved in both risk evaluation and in fear and anxiety-like behavior expression, here we explored whether PL neuronal activity can dynamically represent different internal states of the same behavioral output (i.e., freezing). We found that freezing can always be decoded from PL activity at a population level. However, the sudden presentation of a fearful stimulus quickly reshaped the PL to a new neuronal activity state, an effect not observed in other cortical or subcortical regions examined. This shift changed PL freezing representation and is necessary for fear memory expression. Our data reveal the unique role of the PL in detecting threats and internally adjusting to distinguish between different freezing-related states in both unconditioned and conditioned fear representations.

Exploring Binocular Visual Attention by Presenting Rapid Dichoptic and Dioptic Series.

This study addresses an issue in attentional distribution in a binocular visual system using RSVP tasks under Attentional Blink (AB) experimental protocols. In Experiment 1, we employed dichoptic RSVP to verify whether, under interocular competition, attention may be captured by a monocular channel. Experiment 2 was a control experiment, where a monoptic RSVP assessed by both or only one eye determines whether Experiment 1 monocular condition results were due to an allocation of attention to one eye. Experiment 3 was also a control experiment designed to determine whether Experiment 1 results were due to the effect of interocular competition or to a diminished visual contrast. Results from Experiment 1 revealed that dichoptic presentations caused a delay in the type stage of the Wyble's eSTST model, postponing the subsequent tokenization process. The delay in monocular conditions may be further explained by a visual attenuation, due to fusion of target and an empty frame. Experiment 2 evidenced the attentional allocation to monocular channels when forced by eye occlusion. Experiment 3 disclosed that monocular performance in Experiment 1 differs significantly from conditions with interocular competition. While both experiments revealed similar performance in monocular conditions, rivalry conditions exhibit lower detection rates, suggesting that competing stimuli was not responsible for Experiment 1 results. These findings highlight the differences between dichoptic and monoptic presentations of stimuli, particularly on the AB effect, which appears attenuated or absent in dichoptic settings. Furthermore, results suggest that monoptic presentation and binocular fusion stages were a necessary condition for the attentional allocation.

Unveiling Deceptive Intentions: Insights from Eye Movements and Pupil Size

Recognition of deceptive intentions from the eyes has been of appealing interest in the last decades but is still unresolved. Here, we report the development of a paradigm based on the Concealed Information Test enabling the study of various kinds of deception, that is, faking and concealing. Based on a card game, we compared fixation as well as pupil behaviour while participants were instructed to fake, conceal, or tell the truth. We realized two different layouts of stimulus presentation. Fixations differed between concealing versus faking and telling the truth; pupil size additionally unveiled the object of deception. We infer that various kinds of deceptive behaviour must be carefully distinguished, and contribute to how to use gaze measures as indicators of deceptive intentions.

Influence of Speech Rate on Auditory Recognition in Cochlear Implant Users

Introduction: This study aimed to verify the influence of speech stimulus presentation and speed on auditory recognition in cochlear implant (CI) users with poorer performance. Methods: The cross-sectional observational study applied auditory speech perception tests to fifteen adults, using three different ways of presenting the stimulus, in the absence of competitive noise: monitored live voice (MLV); recorded speech at typical speed (RSTS); recorded speech at slow speed (RSSS). The scores were assessed using the Percent Sentence Recognition Index (PSRI). The data were inferentially analysed using the Friedman and Wilcoxon tests with a 95% confidence interval and 5% significance level (p < 0.05). Results: The mean age was 41.1 years, the mean duration of CI use was 11.4 years, and the mean hearing threshold was 29.7 ± 5.9 dBHL. Test performance, as determined by the PSRI, was MLV = 42.4 ± 17.9%; RSTS = 20.3 ± 14.3%; RSSS = 40.6 ± 20.7%. There was a significant difference identified for RSTS compared to MLV and RSSS. Conclusion: The way the stimulus is presented and the speed at which it is presented enable greater auditory speech recognition in CI users, thus favouring comprehension when the tests are applied in the MLV and RSSS modalities.

Linking Cognitive Integrity to Working Memory Dynamics in the Aging Human Brain.

Aging is accompanied by a decline of working memory, an important cognitive capacity that involves stimulus-selective neural activity that persists after stimulus presentation. Here, we unraveled working memory dynamics in older human adults (male and female) including those diagnosed with mild cognitive impairment (MCI) using a combination of behavioral modeling, neuropsychological assessment, and MEG recordings of brain activity. Younger adults (male and female) were studied with behavioral modeling only. Participants performed a visuospatial delayed match-to-sample task under systematic manipulation of the delay and distance between sample and test stimuli. Their behavior (match/nonmatch decisions) was fit with a computational model permitting the dissociation of noise in the internal operations underlying the working memory performance from a strategic decision threshold. Task accuracy decreased with delay duration and sample/test proximity. When sample/test distances were small, older adults committed more false alarms than younger adults. The computational model explained the participants' behavior well. The model parameters reflecting internal noise (not decision threshold) correlated with the precision of stimulus-selective cortical activity measured with MEG during the delay interval. The model uncovered an increase specifically in working memory noise in older compared with younger participants. Furthermore, in the MCI group, but not in the older healthy controls, internal noise correlated with the participants' clinically assessed cognitive integrity. Our results are consistent with the idea that the stability of working memory contents deteriorates in aging, in a manner that is specifically linked to the overall cognitive integrity of individuals diagnosed with MCI.

Evaluation of Visual Cortex Activity Using Functional Near-Infrared Spectroscopy in Primary Open Angle and Primary Angle Closure Glaucoma: A Pilot Study.

Functional near-infrared spectroscopy (fNIRS) was used to assess visual cortical activity in patients with primary open angle (POAG) and primary angle closure (PACG) glaucomas. There was decreased activity in the visual cortex of glaucoma patients correlating with the severity of glaucoma. To evaluate visual cortex activity using fNIRS in POAG and PACG compared with healthy controls. A total of 30 POAGs, 31 PACGs, and 30 healthy aged-matched controls from a single centre were recruited in this cross-sectional observational pilot study with purposive sampling. The POAG and PACG groups were age-matched but were not matched for disease severity at recruitment. All participants underwent fNIRS testing using a multichannel continuous-wave near-infrared system NIRSport 8×7 device (NIRx Medizintechnik GmbH). The visual cortex activity was evaluated in terms of the maximum amplitude of change in oxyhemoglobin (OxyHb) concentration over 10 seconds, and a comparison was done among 3 groups. Both POAG and PACG groups were combined (termed as glaucoma group) to assess the relationship of visual cortical activity with disease severity (by visual field defect (mean deviation) and retinal nerve fibre layer thickness). All participants showed the characteristic response of increased OxyHb and decreased deoxyhemoglobin during stimulus presentation. The maximum amplitude of change in OxyHb concentration over 10 seconds was significantly lower in both POAG and PACG groups compared with control in the right and left middle occipital gyri ( P < 0.05). There was no significant difference between PACG and POAG. Importantly, there was a negative correlation between the visual cortex activity with the visual field defects (mean deviation; P < 0.05) and a positive correlation with retinal nerve fibre layer thickness in the glaucoma group ( P < 0.05). In patients with glaucoma, a reduction in visual cortical activity was observed, which may be indicative of neuronal degeneration occurring in the occipital cortex. Disease severity in glaucoma appears to be closely correlated with visual cortex activity. fNIRS can serve as a useful neuroimaging modality for assessing the hemodynamic and neurodegenerative changes in glaucoma.

Does Timed Testing Affect the Interpretation of Efficiency Scores?—A GLMM Analysis of Reading Components

AbstractThe efficiency of cognitive component skills is typically assessed with speeded performance tests. Interpreting only effective ability or effective speed as efficiency may be challenging because of the within‐person dependency between both variables (speed‐ability tradeoff, SAT). The present study measures efficiency as effective ability conditional on speed by controlling speed experimentally. Item‐level time limits control the stimulus presentation time and the time window for responding (timed condition). The overall goal was to examine the construct validity of effective ability scores obtained from untimed and timed condition by comparing the effects of theory‐based item properties on item difficulty. If such effects exist, the scores reflect how well the test‐takers were able to cope with the theory‐based requirements. A German subsample from PISA 2012 completed two reading component skills tasks (i.e., word recognition and semantic integration) with and without item‐level time limits. Overall, the included linguistic item properties showed stronger effects on item difficulty in the timed than the untimed condition. In the semantic integration task, item properties explained the time required in the untimed condition. The results suggest that effective ability scores in the timed condition better reflect how well test‐takers were able to cope with the theoretically relevant task demands.

Revisiting the Deviation Effects of Irrelevant Sound on Serial and Nonserial Tasks.

Two types of disruptive effects of irrelevant sound on visual tasks have been reported: the changing-state effect and the deviation effect. The idea that the deviation effect, which arises from attentional capture, is independent of task requirements, whereas the changing-state effect is specific to tasks that require serial processing, has been examined by comparing tasks that do or do not require serial-order processing. While many previous studies used the missing-item task as the nonserial task, it is unclear whether other cognitive tasks lead to similar results regarding the different task specificity of both effects. Kattner et al. (Memory and Cognition, 2023) used the mental-arithmetic task as the nonserial task, and failed to demonstrate the deviation effect. However, there were several procedural factors that could account for the lack of deviation effect, such as differences in design and procedures (e.g., conducted online, intermixed conditions). In the present study, we aimed to investigate whether the deviation effect could be observed in both the serial-recall and mental-arithmetic tasks when these procedural factors were modified. We found strong evidence of the deviation effect in both the serial-recall and the mental-arithmetic tasks when stimulus presentation and experimental design were aligned with previous studies that demonstrated the deviation effect (e.g., conducted in-person, blockwise presentation of sound, etc.). The results support the idea that the deviation effect is not task-specific.

Lateralized displays reveal the perceptual locus of the syllable transposition effect in Korean

Studies of letter transposition effects in alphabetic scripts provide compelling evidence that letter position is encoded flexibly during reading, potentially during an early, perceptual stage of visual word recognition. Recent studies additionally suggest similar flexibility in the spatial encoding of syllabic information in the Korean Hangul script. With the present research, we conducted two experiments to investigate the locus of this syllabic transposition effect. In Experiment 1, lexical decisions for foveal stimulus presentations were less accurate and slower for four-syllable nonwords created by transposing two syllables in a base word as compared to control nonwords, replicating prior evidence for a transposed syllable effect in Korean word recognition. In Experiment 2, the same stimuli were presented to the right and left visual hemifields (i.e., RVF and LVF), which project both unilaterally and contralaterally to each participant's left and right cerebral hemisphere (i.e., LH and RH) respectively, using lateralized stimulus displays. Lexical decisions revealed a syllable transposition effect in the accuracy and latency of lexical decisions for both RVF and LVF presentations. However, response times for correct responses were longer in the LVF, and therefore the RH, as compared to the RVF/LH. As the LVF/RH appears to be selectively sensitive to the visual-perceptual attributes of words, the findings suggest that this syllable transposition effect partly finds its locus within a perceptual stage of processing. We discuss these findings in relation to current models of the spatial encoding of orthographic information during visual word recognition and accounts of visual word recognition in Korean.

Electrophysiological correlates of sustained conscious perception

Previous research on the neural correlates of consciousness (NCC) in visual perception revealed an early event-related potential (ERP), the visual awareness negativity (VAN), to be associated with stimulus awareness. However, due to the use of brief stimulus presentations in previous studies, it remains unclear whether awareness-related negativities represent a transient onset-related response or correspond to the duration of a conscious percept. Studies are required that allow prolonged stimulus presentation under aware and unaware conditions. The present ERP study aimed to tackle this challenge by using a novel stimulation design. Male and female human participants (n = 62) performed a visual task while task-irrelevant line stimuli were presented in the background for either 500 or 1000 ms. The line stimuli sometimes contained a face, which needed so-called visual one-shot learning to be seen. Half of the participants were informed about the presence of the face, resulting in faces being perceived by the informed but not by the uninformed participants. Comparing ERPs between the informed and uninformed group revealed an enhanced negativity over occipitotemporal electrodes that persisted for the entire duration of stimulus presentation. Our results suggest that sustained visual awareness negativities (SVAN) are associated with the duration of stimulus presentation.

Spaced conditioned stimulus presentation facilitates the extinction of strong fear memory in mice

Inducing fear memory extinction by re-presenting a conditioned stimulus (CS) is the foundation of exposure therapy for post-traumatic stress disorder (PTSD). Investigating differences in the ability of different CS presentation patterns to induce extinction learning is crucial for improving this type of therapy. Using a trace fear conditioning paradigm in mice, we demonstrate that spaced presentation of the CS facilitated the extinction of a strong fear memory to a greater extent than continuous CS presentation. These results lay the groundwork for developing more effective exposure therapy techniques for PTSD.

Normative values of the nociceptive blink reflex habituation

Introduction: Habituation is a physiological phenomenon, characterized by response reduction to repeated stimulus presentation. In headache disorders, habituation studies have involved different paradigms with several stimulation parameters and sensory modalities, and consistently showed impaired habituation in primary headaches in the interictal phase. The nociceptive blink reflex (nBR) and its related R2 response, modulated by a polysynaptic network in the trigeminocervical complex, is one of the most studied in the field. The lack of nBR habituation normative data hampered the possibility to draw conclusions regarding the functional status of individual patients. The present study aims to define normative values for the nBR habituation process in healthy subjects without a personal diagnosis and family history of migraine, or other headache disorders.Methods: We enrolled 40 healthy subjects (24 females, 32.7±11.6 years) for nBR recording and nBR habituation assessment. To assess the habituation of nBR, 26 consecutive stimuli were administered at three different and randomized stimulus frequencies (0.2, 0.3, 0.5 Hz). After excluding the first response, the remaining 25 area under the curve (AUC) were divided in 5 blocks, and the average values of the AUC was calculated for each block. The percentage reduction in the AUC of the fifth block, compared to the first, represents the habituation index (HI) value. We considered a one-tailed 10th percentile threshold as the lower threshold of normative values for nBR HI.Results: The habituation phenomenon was confirmed for all study frequencies. The absolute AUC of the R2 component across the five blocks of stimulation was higher in female subjects when compared to male for 0.5 Hz (p=0.021) and 0.2 Hz (p=0.007). We found a frequency-dependent habituation pattern, being lower at the 0.2 Hz stimulation when compared to 0.5 Hz (p=0.001), and 0.3 Hz (p=0.008). The average HIs were 73.1±13.6 at 0.5 Hz, 69.2±15.0 at 0.3 Hz, and 61.1±21.4 at 0.2 Hz. HIs were comparable between male and female subjects, without correlations with age, intensity of stimulation, and latency of the R2 component. The 10th percentile of the HIs was 43.5% for 0.5 Hz, 55.8% for 0.3 Hz, and 28.6% for 0.2 Hz.Conclusions: We investigated the nBR habituation in a population of healthy subjects for normative data collection. We described a frequency- dependent degree of habituation, being more pronounced at higher frequencies of stimulation. Moreover, we described gender-related features of response behaviour, which is extremely important in the migraine field. Our study further characterized the physiological habituation phenomenon in healthy controls exposed to a nociceptive stimulation. The definition of a normative habituation value will open novel possibilities in the study of migraine, as well as other headache and pain disorders.

Low-Level Visual Features of Window Views Contribute to Perceived Naturalness and Mental Health Outcomes.

Previous studies have shown that natural window views are beneficial for mental health, but it is still unclear which specific features constitute a 'natural' window view. On the other hand, studies on image analysis found that low-level visual features (LLVFs) are associated with perceived naturalness, but mainly conducted experiments with brief stimulus presentations. In this study, research on the effects of window views on mental health was combined with the detailed analysis of LLVFs. Healthy adults rated window views from their home and sent in photographs of those views for analysis. Content validity of the 'ecological' view assessment was evaluated by checking correlations of LLVFs with window view ratings. Afterwards, it was explored which of the LLVFs best explained variance in perceived percentage of nature and man-made elements, and in ratings of view quality. Criterion validity was tested by investigating which variables were associated with negative affect and impulsive decision-making. The objective and subjective assessments of nature/sky in the view were aligned but objective brightness was unreliable. The perceived percentage of nature was significantly explained by green pixel ratio, while view quality was associated with fractals, saturation, sky pixel ratio and straight edge density. The higher subjective brightness of rooms was associated with a lower negative affect, whereas results for impulsive decision-making were inconsistent. The research highlights the validity to apply LLVFs analysis to ecological window views. For affect, subjective brightness seemed to be more relevant than LLVFs. For impulsive decision-making, performance context needs to be controlled in future studies.

The Effect of the Symbolic Meaning of Speed on Implicit Timing

Abstract It has been demonstrated that the stimulus’s features, including size, brightness, numerosity, and loudness, can affect the perception of subjective and explicit time. But, in a daily life situation, actual events presumably involve an implicit processing of time rather than an explicit processing, with some studies suggesting that the presentation of emotional stimuli before the target stimulus influences implicit timing. The present study aims to test the implicit component of temporal processing that the symbolic meaning of speed might influence. We used a time foreperiod task in which participants were first presented with a warning signal recalling the meaning of fast or slow speed, followed by the target. Our study shows significant main effects of the presented image cue and foreperiod effect. We observed faster reaction time when the target was preceded by a faster image compared to a slow image and in dependence of the factor of weight. Based on this, we conclude the symbolic meaning of speed can affect implicit timing by altering how the brain interprets temporal data.

Closing a conceptual gap in race perception research: A functional integration of the other-race face recognition and "who said what?" paradigms.

White people confuse Black faces more than their own-race faces. This is an example of the other-race effect, commonly measured by the other-race face recognition task. Like this task, the "Who said what?" paradigm uses within-race confusions in memory, but to measure social categorization strength. The former finds a strongly asymmetrical pattern of interrace perception, the other-race effect, yet the latter usually finds symmetrical patterns (equally strong categorization of own-race and other-race faces). In a "Who said what?" meta-analysis, racial categorization and individuation across races were only weakly asymmetrical (Study 1, n = 2,669). We aimed to resolve this empirical misalignment. As tested in other-race face recognition tasks, the weak asymmetry was not due to the limited number of portrait stimuli (Study 2, N = 99) nor to the longer duration of stimulus presentation in the "Who said what?" task (Study 4, n = 358). Pairing portraits with statements reduced the other-race effect (Study 3, n = 126). Showing each portrait repeatedly also reduced the other-race effect (Study 4, n = 358; Study 5, n = 470) but did not decrease infrahumanization of Black portraits (Study 6, n = 487). Consequently, presenting portraits only once in the "Who said what?" paradigm (Study 7, N = 112) resulted in strong interrace categorization and individuation asymmetries. This finding bridges a central conceptual gap between the other-race effect and social categorization strength. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Unsupervised Characterization of Prediction Error Markers in Unisensory and Multisensory Streams Reveal the Spatiotemporal Hierarchy of Cortical Information Processing.

Elicited upon violation of regularity in stimulus presentation, mismatch negativity (MMN) reflects the brain's ability to perform automatic comparisons between consecutive stimuli and provides an electrophysiological index of sensory error detection whereas P300 is associated with cognitive processes such as updating of the working memory. To date, there has been extensive research on the roles of MMN and P300 individually, because of their potential to be used as clinical markers of consciousness and attention, respectively. Here, we intend to explore with an unsupervised and rigorous source estimation approach, the underlying cortical generators of MMN and P300, in the context of prediction error propagation along the hierarchies of brain information processing in healthy human participants. The existing methods of characterizing the two ERPs involve only approximate estimations of their amplitudes and latencies based on specific sensors of interest. Our objective is twofold: first, we introduce a novel data-driven unsupervised approach to compute latencies and amplitude of ERP components accurately on an individual-subject basis and reconfirm earlier findings. Second, we demonstrate that in multisensory environments, MMN generators seem to reflect a significant overlap of "modality-specific" and "modality-independent" information processing while P300 generators mark a shift toward completely "modality-independent" processing. Advancing earlier understanding that multisensory contexts speed up early sensory processing, our study reveals that temporal facilitation extends to even the later components of prediction error processing, using EEG experiments. Such knowledge can be of value to clinical research for characterizing the key developmental stages of lifespan aging, schizophrenia, and depression.