P300 Component Of Event-related Potential Research Articles

Sibling experience prevents neural tuning to adult faces in 10-month-old infants

Early facial experience provided by the infant's social environment is known to shape face processing abilities, which narrow during the first year of life towards adult human faces of the most frequently encountered ethnic groups. Here we explored the hypothesis that natural variability in facial input may delay neural commitment to face processing by testing the impact of early natural experience with siblings on infants' brain responses. Event-Related Potentials (ERPs) evoked by upright and inverted adult and child faces were compared in two groups of 10-month-old infants with (N = 21) and without (N = 22) a child sibling. In first-born infants, P1 ERP component showed specificity to upright adult faces that carried over to the subsequent N290 and P400 components. In infants with siblings no inversion effects were observed. Results are discussed in the context of evidence from the language domain, showing that neural commitment to phonetic contrasts emerges later in bilinguals than in monolinguals, and that this delay facilitates subsequent learning of previously unencountered sounds of new languages.

Omega-6/omega-3 ratio and cognition in children with epilepsy

IntroductionCognitive impairment is a common consequence of epilepsy in children. This study aimed to assess the ratio of omega-6 to omega-3 fatty acid levels and its impact on cognitive function in children with idiopathic epilepsy. Patients and methodsWe performed a case-control study in 30 children with idiopathic epilepsy and 20 healthy children. We measured levels of alpha-linolenic acid (omega-3) and linoleic acid (omega-6) by means of gas-liquid chromatography. We assessed cognitive function with the Arabic version of the fourth edition of the Stanford-Binet test and the P300 component of event-related potentials. All children had an intelligent quotient greater than 70. ResultsChildren with epilepsy had lower levels of omega-3 and higher levels of omega-6 fatty acids and an abnormal omega-6/omega-3 ratio compared to non-epileptic children. We found a significant positive correlation of serum omega-3 levels and a significant negative correlation of serum omega-6 levels with cognitive function scores and P300 latency in children with epilepsy. ConclusionChildren with epilepsy have abnormal ratios of omega-6 to omega-3 fatty acid serum levels, which is associated with impaired cognitive function in these children.

Electrophysiological markers of poor versus superior math abilities in healthy individuals.

Interindividual differences in the numerical ability of healthy adults have been previously demonstrated, mainly with tasks involving mental number line or size representation. However, electrophysiological correlates of superior versus poor arithmetic ability (in the healthy population) have been scarcely investigated. We correlated electric potentials with math performance in 13 skilled and 13 poor calculators selected from a sample of 41 graduate students on the basis of their poor or superior math abilities assessed through a timed test. EEG was recorded from 128 channels while participants solved 352 arithmetical operations (additions, subtractions, multiplications, divisions) and decided whether the provided solution was correct or incorrect. Overall skilled individuals correctly solved a higher number of operations than poor calculators and had faster response times. Consistently, the latency of fronto-central P300 component of event-related potentials (ERPs) peaked earlier in the skilled than poor group. The P300 was larger in amplitude to correct than incorrect solutions, but just in the skilled group, with a tendency found in poor calculators. Spearman's ρ correlation coefficient analyses showed that the larger P300 response was to correct arithmetic solutions, the better the performance; conversely, the larger the P300 amplitude was to incorrect solutions, the worse the performance. The results suggest that poor calculators had a less clear representation of arithmetic solutions and difficulty in quickly accessing it. This study provides a standard method for directly investigating math abilities throughout ERP recordings that could be useful for assessing acalculia/dyscalculia in the clinical population (children, elderly, brain-damaged patients).

A Randomized Controlled Trial on the Effects of Aerobic and Coordinative Training on Neural Correlates of Inhibitory Control in Children.

Whereas aerobic training has found to be beneficial for inhibitory control, less is known on the efficiency of other exercise types in children. The present study compared the effects of aerobic and coordinative training on behavioral and neurophysiological measures of inhibitory control. Forty-five children were randomly assigned (1:1:1 ratio) to groups performing aerobic training, coordinative training or assisted homework sessions over 10 weeks. Before and after intervention, all participants completed a Flanker task. The P300 component of event-related potentials elicited from the task was recorded via electroencephalography. Additionally, aerobic fitness and gross-motor skills were assessed using 20 m Shuttle Run and Heidelberg Gross-Motor Test, respectively. Statistical analyses revealed no time by group interactions for the P300 component (amplitude, latency), p = 0.976, η2 = 0.007, and behavioral performance (reaction time, accuracy), p = 0.570, η2 = 0.045. In contrast, there was a significant group-difference in pre- to post-test changes in aerobic fitness, p = 0.008, η2 = 0.246, with greater improvements following aerobic and coordinative training compared to assisted homework sessions. In conclusion, no differences regarding the efficiency of aerobic and coordinative training for the enhancement of inhibitory control were found as both exercise programs failed to elicit changes in speed and accuracy of stimulus evaluation and the allocation of attentional resources.

Effects of white noise duration on somatosensory event-related potentials.

Exposure to auditory white noise has been shown to facilitate cognitive function. This phenomenon is called stochastic resonance. The present study examined the effects of white noise duration on behavioral data [reaction time (RT), the SD of RT, and error rates] and the N140 and P300 components of event-related potentials in somatosensory Go/No-go paradigms. A Go or No-go stimulus was presented to the second or fifth digit of the left hand, respectively, at the same probability. Before recording event-related potentials, participants heard three different white noise durations (1, 3, and 5-min conditions), and performed somatosensory Go/No-go paradigms while listening to white noise. RT was significantly shorter under the 5 and 3-min conditions than under the 1-min condition, whereas SD of RT and error rates remained unchanged. The peak latency of Go-P300 was the shortest under the 5-min condition. White noise did not affect the peak latency of N140 or the peak amplitude of N140 or P300. Our results suggest that 5-min white noise exposure accelerated RT and the latency of Go-P300, reflecting changes in the neural activation of response execution processing.

A study of cognitive assessment in Type 2 diabetes mellitus patients

Background: Studying the deleterious effects of Type 2 diabetes mellitus (T2DM) on cognition is gaining a lot of attention. Cognition is measured by the P300 component of event-related potentials (ERPs). Hence, we studied P300 in T2DM. Aims and Objectives: This study was done with the objective to evaluate cognition of T2DM and also to evaluate factors associated with impaired cognition. Materials and Methods: Thirty T2DM and 30 controls matched for their age and gender were selected considering inclusion and exclusion criteria. Cognitive assessment was done using mini-mental state examination, and subjects with scores higher than 25 (maximum score = 30) were included in the study. After ruling out hearing loss by pure tone audiometry, P300 recording was done on them using RMS EMG EP MARK II machine. The resulting data were statistically analyzed. Results: P300 latencies (P < 0.001**) were longer in T2DM when compared with nondiabetics. P300 latencies showed significant positive correlation (r = 0.390*; P = 0.033) with T2DM duration. A significant difference was found in P300 latency between diabetic hypertensives (P = 0.003) and diabetic nonhypertensive, among diabetics with dyslipidemia (P = 0.047) and diabetics without dyslipidemia and between diabetic smokers (P < 0.001) and diabetic non-smokers. Conclusion: Cognitive function of T2DM subjects should be examined on a regular basis using ERPs because there could be an association between T2DM duration and cognitive deterioration. T2DM, along with dyslipidemia, hypertension, and smoking, further aggravates the possibility of cognitive dysfunction. We conclude that dementia can be diagnosed by ERP P300 in the initial phase.

The auditory P300 component of ERPs elicited during the oddball paradigm in type 2 diabetic patients

Background: There is increasing interest in the impact of diabetes mellitus on cognitive functioning. Several studies found evidence of decreased cognitive performance in type 2 diabetics (T2DM). Since the P300 component of event-related potentials (ERPs) provides valuable information concerning cognition, we studied this component of ERPs in T2DM. Methods: Auditory P300 event-related potentials (P300) were elicited in 43 T2DM patients and 29 age and sex-matched healthy volunteers by use of the auditory oddball paradigm, taking into account the age of the subjects, disease duration and the metabolic control. Results: Compared with controls, diabetics had significantly longer P300 latencies (F= 5.05, p= 0.026) and lower P300 amplitudes both in Cz and Pz electrode positions (F= 8.01, p= 0.005 and F= 13.67, p= 0.000 respectively). In addition, a significant inverse correlation between P300 latency and amplitude was observed in diabetics both in Cz and Pz electrode positions (r= -0.43, p= 0.003 and r= -0.39, p= 0.01 respectively), whereas essentially no relationship between amplitude and latency was observed for the control group. N200 and P300 latencies and the reduction in their amplitudes in Cz and Pz leads were not related to either disease duration or metabolic control. Conclusions: The observed electrophysiological abnormalities may reflect impairment of information processing and working memory, possibly associated with an accelerated ageing process. Our findings suggest that surface-recorded ERPs may be useful for detecting and monitoring the changes in brain function associated with diabetes mellitus.

Auditory and Visual Oddball Stimulus Processing Deficits in Schizophrenia and the Psychosis Risk Syndrome: Forecasting Psychosis Risk With P300.

Identification of neurophysiological abnormalities associated with schizophrenia that predate and predict psychosis onset may improve clinical prediction in the psychosis risk syndrome (PRS) and help elucidate the pathogenesis of schizophrenia. Amplitude reduction of the P300 event-related potential component reflects attention-mediated processing deficits and is among the most replicated biological findings in schizophrenia, making it a candidate biomarker of psychosis risk. The relative extent to which deficits in P300 amplitudes elicited by auditory and visual oddball stimuli precede psychosis onset during the PRS and predict transition to psychosis, however, remains unclear. Forty-three individuals meeting PRS criteria, 19 schizophrenia patients, and 43 healthy control (HC) participants completed baseline electroencephalography recording during separate auditory and visual oddball tasks. Two subcomponents of P300 were measured: P3b, elicited by infrequent target stimuli, and P3a, elicited by infrequent nontarget novel stimuli. Auditory and visual target P3b and novel P3a amplitudes were reduced in PRS and schizophrenia participants relative to HC participants. In addition, baseline auditory and visual target P3b, but not novel P3a, amplitudes were reduced in 15 PRS participants who later converted to psychosis, relative to 18 PRS non-converters who were followed for at least 22 months. Furthermore, target P3b amplitudes predicted time to psychosis onset among PRS participants. These results suggest that P300 amplitude deficits across auditory and visual modalities emerge early in the schizophrenia illness course and precede onset of full psychosis. Moreover, target P3b may represent an important neurophysiological vulnerability marker of the imminence of risk for psychosis.

Effects of stimulus intensity and auditory white noise on human somatosensory cognitive processing: a study using event-related potentials

Exposure to auditory white noise has been shown to facilitate cognitive function. This phenomenon is often called stochastic resonance, and a moderate amount of auditory noise has been suggested to benefit individuals in hypodopaminergic states. Previous studies using psychophysic methods reported that stochastic resonance was sensitive to stimulus intensity; however, the relationship between neural activities elicited by different stimulus intensities and auditory white noise has not yet been clarified Thus, the present study aimed to investigate the effects of stimulus intensity (Experiment 1) and auditory white noise (Experiment 2) on behavioral data (reaction time (RT), the standard deviation of RT, and error rates), and the N140 and P300 components of event-related potentials (ERPs) in somatosensory Go/No-go paradigms. The subjects had to respond to the somatosensory stimuli by pressing a button with their right thumb only after presentation of the Go stimulus. In Experiment 1 with four different stimulus intensity levels, the peak latencies of N140 and P300 became shorter, and the peak amplitudes of N140 and P300 were enhanced with increases in stimulus intensity. In Experiment 2 with weak and mild intensities under auditory white noise and control conditions, the amplitudes of Go-P300 and No-go-P300 were enhanced by white noise, irrespective of weak and mild intensities, during Go/No-go paradigms. Auditory white noise did not significantly affect the amplitude of N140 or the latencies of N140 and P300. These results suggest the presence of a characteristic cross-modal stochastic resonance in neural substrates utilizing somatosensory ERPs.

N-back training and transfer effects revealed by behavioral responses and EEG.

IntroductionCognitive function performance decreases in older individuals compared to young adults. To curb this decline, cognitive training is applied, but it is not clear whether it improves only the trained task or also other cognitive functions. To investigate this, we considered an N‐back working memory (WM) training task and verified whether it improves both trained WM and untrained cognitive functions.MethodsAs EEG studies have noted task difficulty and age‐related changes in time‐locked EEG responses, called event‐related potentials (ERPs), we focused on the relation between the P300 ERP component, task difficulty level, and behavior response accuracy and reaction time (RT) in young and older healthy adults. We used two groups of young and older healthy participants to assess the effect of N‐back training: cognitive training group (CTG) and passive control group (PCG). Before and after training, cognitive tests were administered to both groups to evaluate transfer effects.ResultsDespite the observed age‐related differences in the P300 ERP component and in terms of RT and accuracy, our findings demonstrate a stronger improvement in the trained task for older CTGs compared to younger CTGs, larger near‐ and far‐transfer effect to WM and fluid intelligence for both younger and older CTGs, and a far‐transfer effect to attention but only for older adults. Significant differences in response accuracy were shown between young and older subjects in spatial memory and attention tests.ConclusionThe application of a WM training is a promising tool for both healthy adults, and in particular for older subjects, as it showed physiological and behavioral differences in cognitive plasticity across life span and evidence of benefits in the trained task and near‐/far‐transfer effects to other cognitive functions.

Gender Influences on Colour processing: An event related potential (ERP) study

Background: We assessed cognitive function by using different colours. Colour has been used in different neuropsychology tests for diagnostic and therapeutic purposes.Purposes: As male and female hormones are different, it is important to investigate the effect of different colours on the male and female groups for planning their therapeutic strategy in different diseases.Methods: This prospective study was done between 2012 and 2014. We used the 128-sensor net for an event related potential (ERP) study in male and female groups (n= 22 in each group). Different colours were used as stimuli. Subjects pressed ‘button 1’ when they liked the colour and ‘button 2’ when they disliked it. Reaction time (RT) and differences in like and dislike stimuli were analysed. The values of the mean differences of like and dislike stimuli were calculated using a 10-20 electrode system of 19 electrodes. The amplitudes and latencies of the N200 and P300 ERP components were analysed.Results: No significant differences were found in the mean differences of the amplitudes and latencies of the N200 and P300 ERP components between the male and female groups across 19 electrode sites. RTs were non-significantly longer in the male group. However, colour reflected on the frontal-right occipital area in the female group and the frontal-left occipital area in the male group.Conclusion: There might be a possibility of delayed decision-making due to difficulty assessing emotion in the male group compared with the female group.Bangladesh Journal of Medical Science Vol.17(4) 2018 p.612-618

Evidence for a neural dual-process account for adverse effects of cognitive control.

Advantageous effects of cognitive control are well-known, but cognitive control may also have adverse effects, for example when it suppresses the implicit processing of stimulus-response (S-R) bindings that could benefit task performance. Yet, the neurophysiological and functional neuroanatomical structures associated with adverse effects of cognitive control are poorly understood. We used an extreme group approach to compare individuals who exhibit adverse effects of cognitive control to individuals who do not by combining event-related potentials (ERPs), source localization, time-frequency analysis and network analysis methods. While neurophysiological correlates of cognitive control (i.e. N2, N450, theta power and theta-mediated neuronal network efficiency) and task-set updating (P3) both reflect control demands and implicit information processing, differences in the degree of adverse cognitive control effects are associated with two independent neural mechanisms: Individuals, who show adverse behavioral effects of cognitive control, show reduced small-world properties and thus reduced efficiency in theta-modulated networks when they fail to effectively process implicit information. In contrast to this, individuals who do not display adverse control effects show enhanced task-set updating mechanism when effectively processing implicit information, which is reflected by the P3 ERP component and associated with the temporo-parietal junction (TPJ, BA 40) and medial frontal gyrus (MFG; BA 8). These findings suggest that implicit S-R contingencies, which benefit response selection without cognitive control, are always 'picked up', but may fail to be integrated with task representations to guide response selection. This provides evidence for a neurophysiological and functional neuroanatomical "dual-process" account of adverse cognitive control effects.

ERPs Reveal Disengagement Processes Related to Condom Use Embarrassment in Intention-Behavior Inconsistent Young Adults

The use of barrier protections such as condoms has consistently been reported to reduce the acquisition of sexually transmitted infections. However, it has also been reported that the association between condom use intentions and behavior is, at best, often weak. Furthermore, embarrassment associated with purchasing condoms and negotiating their use has been shown to negatively impact the frequency of condom use. Using electroencephalography to analyze P300 event-related potential components known to measure early attention allocation, we examined electrophysiological evidence of early attention disengagement for embarrassing health information. Forty young adults—34 females and six males—participated in an adapted version of Posner’s visual cueing paradigm. All were high in intention to use condoms, but half were intention-behavior consistent and half were intention-behavior inconsistent. Compared to intention-behavior consistent participants, those with intention-behavior inconsistency showed a reduced P300 component when attending to a visual target opposite to the field in which embarrassing self-relevant health information was presented, indicating more efficient early attention disengagement from such embarrassing health information. In conclusion, our electrophysiological data suggest that high intention alone may be not sufficient to predict adolescents’ condom use behavior.

Feedback processing in adolescents with prenatal cocaine exposure: an electrophysiological investigation

ABSTRACTImpaired cognitive control is a consequence of cocaine exposure. Difficulty with feedback processing may underlie this impairment. We examined neural correlates of feedback processing using event-related potentials (ERPs) in 49 prenatally cocaine-exposed (PCE) and 34 nondrug exposed (NDE) adolescents. Adolescents performed a reward-feedback task with win/no-win feedback in a chance-based task. We investigated amplitude and latency of the feedback-related negativity (FRN) and P300 ERP components and source-based estimates elicited during feedback processing. PCE adolescents had smaller P300 amplitudes for no-win feedback, and source analysis in the P300 time window revealed differences between groups localized to the dorsal anterior cingulate cortex.

An Electrophysiological Study of Cognitive and Emotion Processing in Type I Chiari Malformation.

Type I Chiari malformation (CMI) is a neurological condition in which the cerebellar tonsils descend into the cervical spinal subarachnoid space resulting in cervico-medullary compression. Early case-control investigations have indicated cognitive deficits in the areas of attention, memory, processing speed, and visuospatial function. The present study further examined cognitive and emotional processing deficits associated with CMI using a dual-task paradigm. Nineteen CMI patients were recruited during pre-surgical consultation and 19 matched control participants identified emotional expressions in separate single and asynchronous dual-task designs. To extend earlier behavioral studies of cognitive effects in CMI, we recorded event-related potentials (ERPs) in the dual-task design. Though response times were slower for CMI patients across the two tasks, behavioral and ERP analyses indicated that patients did not differ from matched controls in the ability to allocate attentional resources between the two tasks. P1 ERP component analyses provided no indication of an emotional arousal deficit in our CMI sample while P3 ERP component analyses suggested a CMI-related deficit in emotional regulation. P3 analysis also yielded evidence for a frontalization of neurophysiological activity in CMI patients. Pain and related depression and anxiety factors accounted for CMI deficits in single-task, but not dual-task, response times. Results are consistent with a dysfunctional fronto-parietal attentional network resulting from either the indirect effects of chronic pain or the direct effects of CMI pathophysiology stemming from cervico-medullary compression.

Neuro Cognitive Improvement During Pregnancy: An Auditory Event Related Potential (ERP) and Neuropsychological Study

Background: Although there is increasing research interest in auditory cognitive function among pregnant women, little is known about auditory cognitive function during the second (mid) and third trimesters of pregnancy. Therefore, we investigated auditory cognitive and behavioral functions during the mid- and third trimesters of pregnancy using event related potentials (ERPs) and neuropsychological tests, respectively. Methods: ERPs were examined using a 128-sensor net, and the PAS, WCST, ZCT, RAVLTIM, RAVLTDR, RAVLTTS were administered as neuropsychological assessment tools. Thirty-nine participants were recruited as a control group (G1, n=15, non-pregnant), mid trimester (G2, n=12, 13-26 weeks), and third trimester (G3, n=12, 26-40 weeks). The auditory oddball paradigm was used during the ERP examination. Subjects silently counted the number of occurrences of a target tone while ignoring the standard tone. Results: The value of mean differences of two stimuli were measured in case of amplitudes of P50, N100 and P300 ERP components. The highest (significantly) amplitudes were found in three, three and two sites in P50, N100 and P300 ERP components, respectively. Pregnant group (G2 and G3 both) evoked the highest (significantly) amplitudes in three, one and two sites in P50, N100 and P300 components, respectively, comparing with the control group (G1). Within pregnant group, G3 possesses the highest (significantly) amplitudes at 2 sites (out of 3) in P50, 1 site (out of 3) in N100 and 1 site (out of 2) in P300 components. The highest amplitude of P300 was observed in G2 comparing with the G3. G2 subjects achieved the highest (significantly/nearly significantly) scores on the WCST, RAVLTIM; where G1 subjects had the highest score in ZCT among groups. Conclusion: These findings indicate that pregnant women exhibit good auditory attention, memory and executive function. Pregnant women exhibited better auditory cognitive function in the second trimester compared with those in the third trimester of pregnancy.

University-Affiliated Alcohol Marketing Enhances the Incentive Salience of Alcohol Cues

We tested whether affiliating beer brands with universities enhances the incentive salience of those brands for underage drinkers. In Study 1, 128 undergraduates viewed beer cues while event-related potentials (ERPs) were recorded. Results showed that beer cues paired with in-group backgrounds (logos for students’ universities) evoked an enhanced P3 ERP component, a neural index of incentive salience. This effect varied according to students’ levels of identification with their university, and the amplitude of the P3 response prospectively predicted alcohol use over 1 month. In Study 2 (N = 104), we used a naturalistic advertisement exposure to experimentally create in-group brand associations and found that this manipulation caused an increase in the incentive salience of the beer brand. These data provide the first evidence that marketing beer via affiliating it with students’ universities enhances the incentive salience of the brand for underage students and that this effect has implications for their alcohol involvement.

Chronic effects of exercise implemented during school-break time on neurophysiological indices of inhibitory control in adolescents

Abstract Objection The present study investigated the effects of an exercise intervention, which was implemented during school-break time, on the P300 component of event-related potentials and inhibitory control. Methods Adolescents aged 12–15 years were allocated to an exercise and control group. The exercise group performed 20 min of aerobic and coordinative exercise per school day over a period of 8 weeks. Before and after the intervention, stimulus-locked event-related potentials were recorded during a Stroop task using electroencephalography. Cluster-based permutation testing revealed a greater increase of the P300 amplitude in the exercise compared to the control group, most pronounced for the parieto-occipital region. Additionally, increases in P300 amplitude were associated with decreases in incompatible reaction time on the Stroop task. Conclusion An exercise program implemented during school-break time enhances adolescents' inhibitory control. This benefit seems to be due to an improved allocation of attentional resources towards the cognitive task.

Neural activation patterns and connectivity in visual attention during Number and Non-number processing: An ERP study using the Ishihara pseudoisochromatic plates.

Visual cognitive function is important to build up executive function in daily life. Perception of visual Number form (e.g., Arabic digit) and numerosity (magnitude of the Number) is of interest to cognitive neuroscientists. Neural correlates and the functional measurement of Number representations are complex occurrences when their semantic categories are assimilated with other concepts of shape and colour. Colour perception can be processed further to modulate visual cognition. The Ishihara pseudoisochromatic plates are one of the best and most common screening tools for basic red-green colour vision testing. However, there is a lack of study of visual cognitive function assessment using these pseudoisochromatic plates. We recruited 25 healthy normal trichromat volunteers and extended these studies using a 128-sensor net to record event-related EEG. Subjects were asked to respond by pressing Numbered buttons when they saw the Number and Non-number plates of the Ishihara colour vision test. Amplitudes and latencies of N100 and P300 event related potential (ERP) components were analysed from 19 electrode sites in the international 10-20 system. Abrain topographic map, cortical activation patterns and Granger causation (effective connectivity) were analysed from 128 electrode sites. No major significant differences between N100 ERP components in either stimulus indicate early selective attention processing was similar for Number and Non-number plate stimuli, but Non-number plate stimuli evoked significantly higher amplitudes, longer latencies of the P300 ERP component with a slower reaction time compared to Number plate stimuli imply the allocation of attentional load was more in Non-number plate processing. Adifferent pattern of asymmetric scalp voltage map was noticed for P300 components with a higher intensity in the left hemisphere for Number plate tasks and higher intensity in the right hemisphere for Non-number plate tasks. Asymmetric cortical activation and connectivity patterns revealed that Number recognition occurred in the occipital and left frontal areas where as the consequence was limited to the occipital area during the Non-number plate processing. Finally, the results displayed that the visual recognition of Numbers dissociates from the recognition of Non-numbers at the level of defined neural networks. Number recognition was not only a process of visual perception and attention, but it was also related to a higher level of cognitive function, that of language.

The role of phasic norepinephrine modulations during task switching: evidence for specific effects in parietal areas.

Cognitive flexibility is a major requirement for successful goal-directed behavior and their neurobiological underpinnings are becoming better understood. However, the role of the norepinephrine system during task switching is largely enigmatic, despite neurobiological considerations make it likely that the norepinephrine system likely plays an important role. Theoretical considerations also suggest that the norepinephrine system mainly modulates task-switching processes when these rely upon working memory mechanisms. This topic was examined in the current system neurophysiological study integrating event-related potential (ERP) with pupil diameter data as a proximate the norepinephrine system activity. Combined with source localization methods, human brain structure, brain function, and phasic modulations by an important neurobiological system were integrated. The results show that cognitive-neurophysiological subprocesses during the actual switching processes, reflected by the N2 and P3 ERP components, are not modulated by the norepinephrine system. Rather, this system modulates preparatory processes in the fore period of stimuli signaling possible switches of response sets. The source localization results show that this is achieved by modulating neural processes in the temporo-parietal junction (BA40). Importantly, these phasic modulatory effects of the norepinephrine system were only evident when working memory processes had to be used to guide the selection of the appropriate responses for task switching.