Relationship between early and late stages of information processing: an event-related potential study

Exploring the role of working memory gate opening process in creativity: An ERP study using the reference-back paradigm

We investigated the relationship between the gate opening process of working memory and an individual's proficiency in divergent (DT) and convergent thinking (CT) using the reference-back paradigm. Event-related potentials and reaction times were measured across groups with varying DT (N = 40, 27.35 ± 5.05 years) and CT levels (N = 40, 27.88 ± 4.95 years). Based on the role of striatal dopamine in supporting cognitive flexibility, which facilitates DT, and considering the significance of phasic dopamine activity as the gate opening signal originating from the basal ganglia, we assumed that the gate opening process may contribute differently to DT and CT. Despite the absence of behavioural differences in gate opening costs, distinct neural patterns emerged. In the early time windows (P1, N1), gate opening effects were detected in both DT and CT groups, with a notable interaction influenced by the level of DT, resulting in significant effects within the lower DT group. The P2 component showed a gate opening effect only in the higher DT group. In the P3 time window, the process unfolded comparably in all groups. Our results suggest that groups with different levels of convergent thinking (based on Matrix reasoning) and those with lower DT (based on Creativity Index) tend to select and activate the prefrontal cortex representation containing the required task information at an earlier stage, compared to those with better DT. This could be beneficial especially in the early phase of idea generation, as more elements become available to create associations and original ideas.

The psychotomimetic ketamine disrupts the transfer of late sensory information in the corticothalamic network

In prodromal and early schizophrenia, disorders of attention and perception are associated with structural and chemical brain abnormalities and with dysfunctional corticothalamic networks exhibiting disturbed brain rhythms. The underlying mechanisms are elusive. The non-competitive NMDA receptor antagonist ketamine simulates the symptoms of prodromal and early schizophrenia, including disturbances in ongoing and task & sensory-related broadband beta-/gamma-frequency (17-29 Hz/30-80 Hz) oscillations in corticothalamic networks. In normal healthy subjects and rodents, complex integration processes, like sensory perception, induce transient, large-scale synchronised beta/gamma oscillations in a time window of a few hundred ms (200-700 ms) after the presentation of the object of attention (e.g., sensory stimulation). Our goal was to use an electrophysiological multisite network approach to investigate, in lightly anesthetised rats, the effects of a single psychotomimetic dose (2.5 mg/kg, subcutaneous) of ketamine on sensory stimulus-induced oscillations. Ketamine transiently increased the power of baseline beta/gamma oscillations and decreased sensory-induced beta/gamma oscillations. In addition, it disrupted information transferability in both the somatosensory thalamus and the related cortex and decreased the sensory-induced thalamocortical connectivity in the broadband gamma range. The present findings support the hypothesis that NMDA receptor antagonism disrupts the transfer of perceptual information in the somatosensory cortico-thalamo-cortical system.

Attribution of intentions in autism spectrum disorder: A study of event-related potentials

Autism spectrum disorder (ASD) is characterized by social cognition deficits, including difficulties inferring the intentions of others. Although deficits in attribution of intentions (AI) have been consistently replicated in ASD, their exact nature remains unexplored. Here we registered the electrophysiological correlates of a nonverbal social cognition task to investigate AI in autistic adults. Twenty-one male autistic adults and 30 male neurotypical volunteers performed a comic strips task depicting either intentional action (AI) or physical causality with or without human characters, while their electroencephalographic signal was recorded. Compared to neurotypical volunteers, autistic participants were significantly less accurate in correctly identifying congruence in the AI condition, but not in the physical causality conditions. In the AI condition a bilateral posterior positive event-related potential (ERP) occurred 200-400 ms post-stimulus (the ERP intention effect) in both groups. This waveform comprised a P200 and a P300 component, with the P200 component being larger for the AI condition in neurotypical volunteers but not in autistic individuals, who also showed a longer latency for this waveform. Group differences in amplitude of the ERP intention effect only became evident when we compared autistic participants to a subgroup of similarly performing neurotypical participants, suggesting that the atypical ERP waveform in ASD is an effect of group, rather than a marker of low-task performance. Together, these results suggest that the lower accuracy of the ASD group in the AI task may result from impaired early attentional processing and contextual integration of socially relevant cues. LAY SUMMARY: To understand why autistic people have difficulties in inferring others' intentions, we asked participants to judge the congruence of the endings of comic strips depicting either intentional actions (e.g., fetching a chair to reach for something) or situations solely following physical rules (e.g., an apple falling on someone's head), while their electrical brain activity was recorded. Autistic individuals had more difficulties in inferring intentions than neurotypical controls, which may reflect impaired attention and contextual integration of social cues.

Heartbeat-Evoked Cortical Potential during Sleep and Interoceptive Sensitivity: A Matter of Hypnotizability

Individuals with different hypnotizability display different interoceptive sensitivity/awareness (IS) and accuracy (IA), likely sustained by morphofunctional differences in interoception-related brain regions and, thus, possibly also observable during sleep. We investigated the heartbeat-evoked cortical potential amplitude (HEP) during sleep, its association with IS, and the role of hypnotizability in such association. We performed a retrospective analysis of polysomnographic recordings of 39 healthy volunteers. Participants completed the Multidimensional Assessment of Interoceptive Awareness (MAIA), measuring IS and IA, and underwent hypnotic assessment via the Stanford Hypnotic Susceptibility Scale, form A. The amplitude of the early and late HEP components was computed at EEG frontal and central sites. In both regions, the early HEP component was larger in N3 than in N2 and REM, with no difference between N2 and REM. Greater HEP amplitude at frontal than at central sites was found for the late HEP component. HEP amplitudes were not influenced by the autonomic state assessed by heart rate variability in the frequency and time domains. We report for the first time a positive correlation between the central late HEP component and MAIA dimensions, which became non-significant after removing the effects of hypnotizability. Our findings indicate that hypnotizability sustains the correlation between IS and HEP amplitude during sleep.

Does mobile payment change consumers' perception during payment process? -An ERP study

Innovative payment methods have been getting worldwide attention. Exploring the mechanisms behind consumers' purchase behaviors modulated by different payment methods was critical but challenging. In this paper, we proposed a 2 (payment methods: cash payment vs mobile payment) × 2 (price levels of products: high vs low) Event-Related Potentials (ERPs) experiment to study the difference of cash payment and mobile payment on consumers' purchase intention of products in different price level from a neuroscience perspective. Greater P200 amplitude was found in mobile payment condition, which meant that mobile payment captured more early attention resources than cash. Larger N270 amplitude was found in cash payment condition as the participants had to spend more cognitive resources and struggled more when using cash. Moreover, lower N270 amplitude was found in high-price product condition, which indicated that when there were limited cognitive resources, the affective process played a dominating role. Specifically, buying the high-price products with mobile payment, the consumers would experience the pleasure of consumption more rather than the pain of paying. The study offers insights on the cognitive process of consumers when they pay with different methods.

Brain-behavior relationships in the perceptual decision-making process through cognitive processing stages

Perceptual decision making - the process of detecting and categorizing information - has been studied extensively over the last two decades. In this study, we aim to bridge the gap between neural and behavioral representations of the perceptual decision-making process. The neural characterization of decision-making was investigated by evaluating the duration and neural signature of the information processing stages. We further evaluated the processing stages of the decision-making process at the behavioral level by estimating the drift rate and non-decision time parameters. We asked whether the neural and behavioral characterizations of the decision-making process provided consistent results under different stimulus coherency levels and spatial attention. Our statistical analysis revealed that, at both representational levels, decision-making was affected more by the coherency factor. We further found that among different information processing stages, the decision stage had the highest role in the performance of the decision-making process. Such that, the shorter decision stage duration at the neural level and higher drift rate at the behavioral level lead to faster decision-making. Through our consistent neural and behavioral results, we have shown that the decision-making components at these two representational levels were significantly associated. Moreover, the neural signature of the processing stages gave information about the regions that contributed more to the decision-making process. Our overall results demonstrate that uncovering the cognitive processing stages provided more insights into the decision-making process.

Brain Processing of Complex Geometric Forms in a Visual Memory Task Increases P2 Amplitude

We study the cognitive processing of visual working memory in three different conditions of memory load and configuration change. Altering this features has been shown to alter the brain's processing in memory tasks. Most studies dealing with this issue have used the verbal-phonological modality. We use complex geometric polygons to assess visual working memory in a modified change detection task. Three different types of backgrounds were used to manipulate memory loading and 18 complex geometric polygons to manipulate stimuli configuration. The goal of our study was to test whether the memory load and configuration affect the correct-recall ratios. We expected that increasing visual items loading and changing configuration of items would induce differences in working memory performance. Brain activity related to the task was assessed through event-related potentials (ERP), during the test phase of each trial. Our results showed that visual items loading and changing of item configuration affect working memory on test phase on ERP component P2, but does not affect performance. However frontal related ERP component-P3-was minimally affected by visual memory loading or configuration changing, supporting that working memory is related to a filtering processing in posterior brain regions.

Early cognitive processes in OCD: An ERP study

BACKGROUND

Obsessive-compulsive disorder (OCD) is characterized by persistent, intrusive, and distressing obsessions and/or compulsions and is associated with marked impairments in quality of life. The goal of the present study was to examine initial stages of information processing, specifically, perceptual and attention orientation phases that precede response preparation in OCD.

METHODS

The P3 event-related potential (ERP) component was used as a measure of early cognitive processes of visual stimulus perception. ERPs were recorded while 38 participants diagnosed with OCD and 38 healthy controls performed a passive visual oddball task with neutral and angry schematic faces.

RESULTS

OCD participants demonstrated significantly enhanced P3 amplitude over bilateral parietal areas in response to neutral stimuli that activate basic primary perceptual processes. Emotional valence reduced this effect such that OCD patients did not differ from healthy controls in P3 amplitude under the angry stimuli condition.

LIMITATIONS

Patients in this study were noncomorbid and unmedicated partially limiting the generalizability of the results.

CONCLUSIONS

Our hypothesis of altered early perceptual processes in OCD was supported. These alterations, specific to OCD and not anxiety and depression symptoms, may represent distracted primary cognitive processes in OCD, possibly serving as a basic source for compulsion initiation.

Do Event-Related Evoked Potentials Reflect Apathy Tendency and Motivation?

Apathy is a mental state of diminished motivation. Although the reward system as the foundation of the motivation in the human brain has been studied extensively with neuroimaging techniques, the electrophysiological correlates of motivation and apathy have not been fully explored. Thus, in 14 healthy volunteers, we examined whether event-related evoked potentials (ERP) obtained during a simple number discrimination task with/without rewards reflected apathy tendency and a reward-dependent tendency, which were assessed separately using the apathy scale and the temperament and character inventory (TCI). Participants were asked to judge the size of a number, and received feedback based on their performance in each trial. The P3 amplitudes related to the feedback stimuli increased only in the reward condition. Furthermore, the P2 amplitudes related to the negative feedback stimuli in the reward condition had a positive correlation with the reward-dependent tendency in TCI, whereas the P3 amplitudes related to the positive feedback stimuli had a negative correlation with the apathy score. Our result suggests that the P2 and P3 ERPs to reward-related feedback stimuli are modulated in a distinctive manner by the motivational reward dependence and apathy tendency, and thus the current paradigm may be useful for investigating the brain activity associated with motivation.

Event-Related Potentials Altered in Patients with Borderline Personality Disorder during Working Memory Tasks

Whereas some studies have demonstrated impaired working memory (WM) among patients with borderline personality disorder (BPD), these findings have not been consistent. Furthermore, there is a lack of neurophysiological evidence about WM function in patients with BPD. The goal of this study was to examine WM function in patients with BPD by using event-related potentials (ERPs). An additional goal was to explore whether characteristics of BPD (i.e., impulsiveness and emotional instability) are associated with WM impairment. A modified version of the N-back task (0- and 2-back) was used to measure WM. ERPs were recorded in 22 BPD patients and 21 age-, handedness-, and sex-matched healthy controls (HCs) while they performed the WM task. The results revealed that there were no significant group differences for behavioral variables (reaction time and accuracy rate) or for latencies and amplitudes of P1 and N1 (all p > 0.05). BPD patients had lower P3 amplitudes and longer N2 latencies than HC, independent of WM load (low load: 0-back; high load: 2-back). Impulsiveness was not correlated with N2 latency or P3 amplitude, and no correlations were found between N2 latency or P3 amplitude and affect intensity scores in any WM load (all p > 0.05). In conclusion, the lower P3 amplitudes and longer N2 latencies in BPD patients suggested that they might have some dysfunction of neural activities in sub-processing in WM, while impulsiveness and negative affect might not have a close relationship with these deficits.

Testing the Limits of Skill Transfer for Scrabble Experts in Behavior and Brain

We investigated transfer of the skills developed by competitive Scrabble players. Previous studies reported superior performance for Scrabble experts on the lexical decision task (LDT), suggesting near transfer of Scrabble skills. Here we investigated the potential for far transfer to a symbol decision task (SDT); in particular, transfer of enhanced long-term working memory for vertically presented stimuli. Our behavioral results showed no evidence for far transfer. Despite years of intensive practice, Scrabble experts were no faster and no more accurate than controls in the SDT. However, our fMRI and EEG data from the SDT suggest that the neural repertoire that Scrabble experts develop supports task performance even outside of the practiced domain, in a non-linguistic context. The regions engaged during the SDT were different across groups: controls engaged temporal-frontal regions, whereas Scrabble experts engaged posterior visual and temporal-parietal regions. In Scrabble experts, activity related to Scrabble skill (anagramming scores) included regions associated with visual-spatial processing and long-term working memory, and overlapped with regions previously shown to be associated with Scrabble expertise in the near transfer task (LDT). Analysis of source waveforms within these regions showed that participants with higher anagramming scores had larger P300 amplitudes, potentially reflecting greater working memory capacity, or less variability in the participants who performed the task more efficiently. Thus, the neuroimaging results provide evidence of brain transfer in the absence of behavioral transfer, providing new clues about the consequences of long-term training associated with competitive Scrabble expertise.

Cortical arousal in children and adolescents with functional neurological symptoms during the auditory oddball task

OBJECTIVE

Stress, pain, injury, and psychological trauma all induce arousal-mediated changes in brain network organization. The associated, high level of arousal may disrupt motor-sensory processing and result in aberrant patterns of motor function, including functional neurological symptoms. We used the auditory oddball paradigm to assess cortical arousal in children and adolescents with functional neurological symptom disorder.

METHOD

Electroencephalogram (EEG) data was collected in fifty-seven children and adolescents (41 girls; 16 boys, aged 8.5-18 years) with acute functional neurological symptoms and age- sex- matched controls during a conventional auditory oddball task. The high-resolution fragmentary decomposition technique was used to analyse the amplitude of event-related potentials (ERPs) to target tones at midline sites (Fz, Cz, and Pz).

RESULTS

Compared to age- and sex-matched controls, and across all three midline sites, children and adolescents with functional neurological symptoms showed increased amplitude of all ERP components (P50, N100, P200, N200, and P300) (t-value range 2.28-8.20; p value-range 0.023 to < 0.001) to the emotionally-neutral auditory stimulus.

CONCLUSIONS

Our findings add to a growing literature indicating that a baseline state of high arousal may be a precondition for generating functional neurological symptoms, a finding that helps explain why a range of psychological and physiological stressors can trigger functional neurological symptoms in some patients. Interventions that target cortical arousal may be central to the treatment of paediatric patients with functional neurological symptom disorder.

Evaluation of passive polarized stereoscopic 3D display for visual & mental fatigues

Visual and mental fatigues induced by active shutter stereoscopic 3D (S3D) display have been reported using event-related brain potentials (ERP). An important question, that is whether such effects (visual & mental fatigues) can be found in passive polarized S3D display, is answered here. Sixty-eight healthy participants are divided into 2D and S3D groups and subjected to an oddball paradigm after being exposed to S3D videos with passive polarized display or 2D display. The age and fluid intelligence ability of the participants are controlled between the groups. ERP results do not show any significant differences between S3D and 2D groups to find the aftereffects of S3D in terms of visual and mental fatigues. Hence, we conclude that passive polarized S3D display technology may not induce visual and/or mental fatigue which may increase the cognitive load and suppress the ERP components.

Attention-related EEG markers in adult ADHD

ADHD status affects both bottom-up sensory processing and top-down attentional selection, impairing professional and social functioning. The objective of the study was to investigate the functional mechanisms of attention deficits in adult ADHD by examining the electrophysiological activities associated with bottom-up attentional cueing (temporal and spatial orienting of attention) and top-down control (conflict resolution). Continuous EEG was recorded in 21 adult ADHD patients (40.05±9.5 years) and 20 healthy adults (25.5±4 years) during performance of the Attention Network Test (ANT). We examined the cue and target-related P1, N1 and P3 components as well as the contingent negative variation (CNV) developing between cue and target. Oscillatory responses were analyzed in the alpha (8-13Hz) and beta (14-19Hz) frequency bands. ADHD patients performed similarly to controls but showed reduced P3 amplitude, larger early CNV decrementing over time, reduced preparatory activation in both alpha and beta bands, as well as flattened target-related posterior alpha and beta responses. As compared to controls, the inverted CNV pattern suggested peculiar preparatory processing in ADHD patients. The singular pattern of target-related beta response indicated increased inhibitory processes in the case of easier task resolution and more generally, the lack of association between conflict resolution speed and beta activity supported alternative executive processing in ADHD patients. Overall, the reduced activation of the functional networks devoted to bottom-up and top-down attention suggests that adult ADHD patients engage reduced cortical resources in this composite task, compatible with the cortical hypoarousal model.

Differences in early and late stages of information processing between slow versus fast participants

The human brain is a system consisting of various interconnected neural networks, with functional specialization coexisting with functional integration occurring both; temporally and spatially at many levels. The current study ranked and compared fast and slow participants in processing information by assessing latency and amplitude of early and late Event-Related Potential (ERP) components, including P200, N200, Premotor Potential (PMP) and P300. In addition, the Reaction Time (RT) of participants was compared and related to the respective ERP components. For this purpose, twenty right-handed and healthy individuals were subjected to a classical ERP “Oddball” paradigm. Principal Component Analysis (PCA) and Discriminant Function analyses (DFA) used PRE components and the Reaction Time (RT) to classify individuals. Our results indicate that latencies of P200 (O2 electrode), N200 (O2), PMP (C3) and P300 (Pz) components are significantly reduced in the group of fast responding participants. In addition, the P200 amplitude is significantly increased in the group of fast responding participants. Based on these findings, we suggest that the ERP is able to detect even minimal impairments, in the processing of somatosensory information and cognitive and motor stages. Hence, the study of ERP might also be capable of assessing sensorimotor dysfunctions in healthy old-aged people and in neuropsychiatric patients (suffering from dementia, Parkinson’s disease, and other neurological disorders).

EEG biofeedback improves attentional bias in high trait anxiety individuals

Background

Emotion-related attentional bias is implicated in the aetiology and maintenance of anxiety disorders. Electroencephalogram (EEG) biofeedback can obviously improve the anxiety disorders and reduce stress level, and can also enhance attention performance in healthy subjects. The present study examined the effects and mechanisms of EEG biofeedback training on the attentional bias of high trait anxiety (HTA) individuals toward negative stimuli.

Results

Event-related potentials were recorded while HTA (n=24) and nonanxious (n=21) individuals performed the color-word emotional Stroop task. During the emotional Stroop task, HTA participants showed longer reaction times and P300 latencies induced by negative words, compared to nonanxious participants.

The EEG biofeedback significantly decreased the trait anxiety inventory score and reaction time in naming the color of negative words in the HTA group. P300 latencies evoked by negative stimuli in the EEG biofeedback group were significantly reduced after the alpha training, while no significant changes were observed in the sham biofeedback group after the intervention.

Conclusion

The prolonged P300 latency is associated with attentional bias to negative stimuli in the HTA group. EEG biofeedback training demonstrated a significant improvement of negative emotional attentional bias in HTA individuals, which may be due to the normalization of P300 latency.