event-related potentials

Stuttering is a neurodevelopmental disorder with structural and functional neurological bases characterized by involuntary prolongations, repetitions and blocks in sounds, syllables and words. Multiple factors are assumed to participate in etiology and severity of stuttering and response inhibition is considered to be an important phenomenon for having a fluent speech. Therefore, this study aimed to evaluate response inhibition of Adults Who Stutter (AWS).

In a case-control study, response inhibition of twenty-eight AWS and fluently-matched control group was compared by a visual stop-signal task and its evoked potentials in the brain. Behavioral measurements of the task, including the Reaction Time (RT) and the response accuracy, were compared between the two groups. Peak amplitude and peak latency of P3 and N2 components in parietal and frontal areas were measured after cue, go and stop stimuli in different trials of the task.

Although AWS reported more scores in anxiety level, they acted similarly to the control group in behavioral measurements. ERP findings, however, represented smaller N2 amplitude in the cues and earlier N2 latency for the Go trials in AWS than in the controls.

Our findings did not support the idea of less efficient inhibitory control in AWS; however, smaller N2 amplitude in the cues may indicated decreased attention resources allocated to the stimuli and different preparation for executing the response. Earlier N2 latency for Go trials in AWS also showed different timing of mental access to go stimuli and faster conflict monitoring in competing stimuli.

Perceptual decision-making is the act of choosing one option from a set of alternatives based on available sensory information. Regarding the serious role of this act in human personal and social lives, the neurophysiological analysis of the brain during this type of decision is of great interest. In this research, the underlying neural mechanism of these decisions is investigated using a perceptual decision-making Electroencephalogram (EEG) dataset with a perceptual discrimination task.

An online available dataset containing the pre-processed EEG signals of 24 healthy participants during the perceptual decision-making task of Random Dot Kinematograms was used. After a secondary pre-processing stage, clean EEG signal was divided into 1.3-second segments and averaged for Event-Related Potential (ERP) and Event-Related Spectral Perturbation (ERSP) calculations. The task engagement index was also calculated and averaged among all participants.

According to the results, the amplitude of the N200 component in O1 and O2 channels was larger for correct choices than incorrect ones. Furthermore, in the O2 channel, it was observed that the average alpha power near 200 milli-seconds after stimulus onset was slightly higher in high and low confidence choices than medium confidence choices. The beta band power in the PO2 channel was also higher for correct choices rather than incorrect ones in this interval. Moreover, the results represented that the task engagement index was higher in medium confidence choices, especially in occipital and parieto-occipital channels.

The larger N200 amplitude and the higher beta power for correct choices, and the lower alpha power for medium confidence choices may be due to more attention of the individuals to the stimuli. This phenomenon can be observed in the task engagement indices as well. This could be because the user expended more efforts in medium confidence to bring one of the choices to the decision threshold.

In recent years, galvanic vestibular stimulation (GVS) has been used as an effective method in rehabilitation and treatment of psychological disorders in children and adults. This study was designed to evaluate the effect of GVS on response inhibition and susta ined attention in children with attention-deficit/hyperactivity disorder (ADHD).

Seventeen children with ADHD, within the age range of 9−12 years, participated in this study. All participants were exposed to the go/no-go task. The behavioral outcomes and event-related potentials were recorded at baseline status, in sham condition, and after 20 minutes of exposure to GVS polarities, with an anode on the right mastoid region and a cathode on the left mastoid region.

The results showed that there was a significant difference in reducing the behavioral response of the commission error (p < 0.05). But the reduction in behavioral responses to omission error and reaction time were not significant (p > 0.05). However, regarding ERPs, reduced latencies and increased amplitudes of N2 and P3 waves were observed in GVS intervention, compared to the baseline and sham conditions (p < 0.05).

The present results indicated the potential of GVS in improving of cognition function in children with ADHD and could help us develop a new strategy for rehabilitation of response inhibition disorders in the future.

Constraint-induced movement therapy (CIMT) has shown positive results in children with hemiplegic cerebral palsy (CP). However, studies on neural basis of such functional gains are limited. This study reports the event-related potential (ERP) changes in two children with hemiplegic CP after receiving CIMT for three weeks. Both cases were nine years old, had a diagnosis of left hemiplegic CP, had normal intelligence, and were able to extend the wrist at least 20° and the metacarpophalangeal joint at least 10° from full flexion. Before and after the three-week intervention, the children participated in ERP sessions with a choice reaction task to capture the changes in neural mechanism after intervention. Both children exhibited improvement in reaction time (RT) in both hand tasks after the intervention. The improvement was larger in the affected hand than the unaffected hand. Improved accuracy rate (AC) and shortened P300 latencies in the affected hand were also demonstrated in both cases. Topographical maps showed that in centro-parietal regions, patterns shifted from central and left-lateralized to more central and right-lateralized. CMIT was a useful method in improving upper limb function in our cases.

Considering the common neurological origins, there is a relationship between the sensory gating and cognitive functions. However, there is no adequate information on this issue. In this study, auditory event-related potentials and the sensory gating performance were assessed in P50, N100 and P200 waves. Besides, their relationship with cognitive performance in auditory and visual modalities was investigated. Nineteen normal primary school students (14 boys) were tested in Tehran, Iran from 2017 to 2018. In the auditory modality, the Persian version of the non-word repetition test and monaural selective auditory attention test (mSAAT) were used for assessment of the working memory and selective attention, respectively. In order to evaluate the visual working memory and visual selective attention, Rey-Osterrieth complex figure, selective and divided attention test were used, respectively. A 32-channel EEG system was used for electrophysiological assessment. The P50 sensory gating was negatively correlated with the visual selective attention (P=0.034, r=-0.49) and N100 sensory gating was negatively correlated with the auditory working memory (P=0.043, r=-0.48) as well as visual selective attention (P=0.039, r=-0.47). For P200, there was a significant negative relationship with auditory selective attention in the right ear (P=0.034, r=-0.49).ConclusionSensory gating in children is not a modality-specific phenomenon. Sensory gating in a modality could be associated with cognitive functions in other modalities

Event-related potentials (ERPs) have been used in addiction studies to evaluate cognitive performance and craving in individuals with substance use dependence (SUD). This paper reviews studies that used ERPs to investigate cue reactivity, inhibitory control and error processing in SUDs. Five abused substances are included in the investigation, i.e. alcohol, nicotine, cannabis, cocaine, and methamphetamine. For each substance, the main recent findings related to the ERPs are specifically discussed, according to the latency of ERPs.


The results show that individuals with SUDs allocate more attention resources to the cognitive processing of substance-related cues, indexed by increased amplitude of middle and late latency ERPs. Laboratory observations also show amplitude enlargement for early latency ERPs. SUDs reveal a deficiency in the inhibitory control and conscious error processing, indexed by attenuated N2 and Pe amplitude. The cognitive and motor inhibitory component (P3) changes show a controversial result.


This study expands the findings of previous related reviews implying that substance abusers allocate more attentional resources to drug cues indexed by enlarged P3 and LPP amplitude. Regarding P3 elicited in inhibitory control tasks, there is not still convergent results, while N2 and Pe become attenuated as reported in previous reviews. The outcomes also show that the chance of relapse to substance abuse could be predicted by recording ERPs reflecting inhibitory control and error processing.

This study examines semantic encoding in mild cognitive impairment (MCI) using the event-related potential (ERP) technique. Subsequent memory effect (SME) is used as an index of successful memory encoding. Typically, SMEs are positive at P550 and late positive component (LPC) time windows.
Ten MCI participants were recruited to complete the ERP experiment. A study and recognition paradigm was employed. Participants determined whether the item referred to by the Chinese character was able to produce sound at study phase and whether the Chinese character was studied at recognition phase while having their electroencephalograms recorded.
Behaviourally, correct percentage at study was 81% and reaction time was 998.5±325.5. Correct percentage at recognition was 61% (d prime=0.87±0.7). Significant SMEs were not identified in P550 and LPC windows.
The behavioural and ERP results showed extensive cerebral deficits in MCI when performing semantic encoding. These deficits may be associated with assessing semantic memory and binding new information with long-term memory store.

Auditory P300 is an event-related potential. Cognitive factors like attention are involved in the generation of P300. It seems that normative variation of P300 is necessary for clinical purposes. Thus, the current study was designed to establish preliminary normative variation of P300 amplitude and latency at Fz and Cz sites in adults.
This cross-sectional study was performed on 20 right-handed volunteers aged 18 to 33 years. P300 was recorded monaurally with two channels at Fz and Cz placements. Two tone bursts of 1000Hz and 2000Hz were used as frequent and target stimuli, respectively.
The mean values of P300 amplitude and latency at Cz were 7.43±2.61 µv and 325.19±21.34 ms in the right ear and 7.38±2.73µv and 320.29±21.56 ms in the left ear, respectively. At Fz, the mean values of P300 amplitude and latency were 5.34±1.74 µv and 330.09±25.58 ms in the right ear and 5.67±2.30 µv and 329.52±29.25 ms in the left ear, respectively. The differences between the ears at Cz and Fz were not statistically significant (p˃0.05).The mean value of amplitude of P300 was significantly greater at Cz than Fz (p=0.001) although the difference in latency was not statistically significant between Cz and Fz (p˃0.05).
Amplitude of P300 was greater at Cz than Fz although latency was not different. Based on these findings, amplitude and latency values can be probably used for clinical purposes to assess auditory disorders.