P300 Event-related Potential Research Articles

Hydrogel electrodes with conductive and substrate-adhesive layers for noninvasive long-term EEG acquisition

Noninvasive brain–computer interfaces (BCIs) show great potential in applications including sleep monitoring, fatigue alerts, neurofeedback training, etc. While noninvasive BCIs do not impose any procedural risk to users (as opposed to invasive BCIs), the acquisition of high-quality electroencephalograms (EEGs) in the long term has been challenging due to the limitations of current electrodes. Herein, we developed a semidry double-layer hydrogel electrode that not only records EEG signals at a resolution comparable to that of wet electrodes but is also able to withstand up to 12 h of continuous EEG acquisition. The electrode comprises dual hydrogel layers: a conductive layer that features high conductivity, low skin-contact impedance, and high robustness; and an adhesive layer that can bond to glass or plastic substrates to reduce motion artifacts in wearing conditions. Water retention in the hydrogel is stable, and the measured skin-contact impedance of the hydrogel electrode is comparable to that of wet electrodes (conductive paste) and drastically lower than that of dry electrodes (metal pin). Cytotoxicity and skin irritation tests show that the hydrogel electrode has excellent biocompatibility. Finally, the developed hydrogel electrode was evaluated in both N170 and P300 event-related potential (ERP) tests on human volunteers. The hydrogel electrode captured the expected ERP waveforms in both the N170 and P300 tests, showing similarities in the waveforms generated by wet electrodes. In contrast, dry electrodes fail to detect the triggered potential due to low signal quality. In addition, our hydrogel electrode can acquire EEG for up to 12 h and is ready for recycled use (7-day tests). Altogether, the results suggest that our semidry double-layer hydrogel electrodes are able to detect ERPs in the long term in an easy-to-use fashion, potentially opening up numerous applications in real-life scenarios for noninvasive BCI.

Aging and sex effects on phoneme perception: An exploratory mismatch negativity and P300 investigation

Background & aimsThe mismatch negativity (MMN) and P300 event-related potentials (ERPs) have been studied in relation to phoneme discrimination and categorization, respectively. Although the effects of aging and sex on pure-tone perception have been widely investigated using these ERPs, evidence relating to phoneme perception is scarce. The current study aimed to provide insight into the effects of aging and sex on phoneme discrimination and categorization, as measured through the MMN and P300. MethodAn inattentive and attentive oddball paradigm containing a phonemic articulation place contrast were administered during EEG registration in sixty healthy individuals (thirty males and females), of which an equal number of young (20–39 years), middle-aged (40–59 years) and elderly (60+ years) subjects were included. The amplitude, onset latency and topographical distribution of the MMN and P300 effect, as well as the amplitude of the P1-N1-P2 complex, were analyzed for age group and sex differences. ResultsWith respect to aging, elderly subjects demonstrated a reduced MMN and P300 amplitude compared to the young group, whereas the scalp distribution of both components was unaffected. No aging effects on the P1-N1-P2 complex were found. In elderly individuals, the P300 was found to be delayed compared to the young group, while no such effect on MMN latency could be observed. No differences in MMN and P300 measures could be identified between males and females. ConclusionDifferential effects of aging were found on the MMN and P300, specifically in terms of latency, in relation to phoneme perception. In contrast, sex was found to scarcely affect both processes.

The P3 ERP in Relation to General Versus Specific Psychopathology in Early Childhood.

There is considerable covariation between externalizing and internalizing problems across the lifespan. Partitioning general and specific psychopathology is crucial to identify (a) processes that confer specific risk for externalizing versus internalizing problems and (b) transdiagnostic processes that confer risk for the covariation between externalizing and internalizing problems. The oddball P3 event-related potential (ERP) component, thought to reflect attentional orienting, has been widely examined in relation to psychopathology. However, prior studies have not examined the P3-or other aspects of neural functioning-in relation to general versus specific psychopathology in children. The present study examined whether children's (N = 124, ages 3-7years) P3 amplitudes were associated with general versus specific psychopathology. Children's electroencephalography data were recorded during an oddball task. Parents rated their children's externalizing and internalizing problems. Using bifactor models to partition variance in parents' ratings of children's psychopathology symptoms, we examined children's P3 amplitudes in relation to three latent factors: (1) the general factor of psychopathology-the covariation of externalizing and internalizing psychopathology, (2) unique externalizing problems-the variance in externalizing problems after controlling for the general factor, and (3) unique internalizing problems. Results indicated that smaller P3 amplitudes were associated with unique externalizing problems at ages 3-5, and with general psychopathology at ages 6-7. Findings suggest that smaller P3 amplitudes may be associated with externalizing problems from a very young age. Moreover, there may be a developmental shift in the functional significance of the P3 in relation to general and specific psychopathology in childhood.

Reduced Visual Evoked Potential Amplitude in Autistic Children with Co-Occurring Features of Attention-Deficit/Hyperactivity Disorder.

Provided the significant overlap in features of autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), there is a critical need to identify transdiagnostic markers that could meaningfully stratify subgroups. The objective of this study was to compare the visual evoked potential (VEP) between 30 autistic children, 17 autistic children with co-occurring ADHD presentation (ASD + ADHD), and 21 neurotypical children (NTC). Electroencephalography was recorded while children passively viewed a pattern-reversal stimulus. Mean amplitude of the P1 event-related potential was extracted from a midline occipital channel and compared between groups. P1 mean amplitude was reduced in the ASD + ADHD group compared to the ASD and NTC groups, indicating a distinct pattern of brain activity in autistic children with co-occurring ADHD features.

Effect of repetitive transcranial magnetic stimulation combined with transcranial direct current stimulation on post-stroke dysmnesia: A preliminary study

ObjectiveThis study examined the effect of repetitive transcranial magnetic stimulation (rTMS) combined with transcranial direct current stimulation (tDCS) as a bimodal neuromodulatory approach for post-stroke dysmnesia. MethodsThirty-four patients with post-stroke dysmnesia were randomly allocated into a sham group treated with neither rTMS nor tDCS, a group treated with rTMS, and a group treated with a combination of rTMS and tDCS. All three groups received cognitive rehabilitation training for 4 weeks. The memory function of each group before and after the intervention was assessed using the Montreal Cognitive Assessment (MoCA) and Rivermead Behavioral Memory Test (RBMT) scales, as well as in terms of the Mismatch Negativity（MMN）and P300 of event-related potentials. ResultsThe sham, rTMS, and rTMS–tDCS groups all showed improvement in the total MoCA score after the intervention. Delayed recall, a MoCA item, scored better in the rTMS–tDCS group than in the rTMS and sham groups. Delayed processing, an RBMT item, scored better in the rTMS–tDCS combination group than in the rTMS and sham groups. MMN and P300 latency was significantly shorter in the rTMS–tDCS combination group. ConclusionrTMS–tDCS bimodal stimulation was more effective than cognitive rehabilitation or rTMS alone in treating patients with post-stroke dysmnesia, offering new possibilities for enhancing cognitive function and treating post-stroke dysmnesia.

Effects of Smoking Social Cues on Inhibitory Control in Smokers: An Event-Related Potential Study

ObjectiveReduced inhibitory control is a general characteristic of smokers and becomes increasingly pronounced in smoking-related contexts. However, research has rarely considered differences in the effects of various smoking-related cues. To fill this research gap, this study compared the effects of smoking object-related and smoking social-related cues on inhibitory control in smokers. MethodsWe used a visual Go/NoGo paradigm with three types of long-lasting backgrounds (neutral, smoking object, and smoking social background) to record the error rates, reaction times, and amplitudes of the N2 and P3 event-related potentials (ERPs) by 25 smokers and 25 non-smokers. Results(1) Smokers displayed smaller NoGo-N2 amplitudes than controls under the neutral background; (2) smokers displayed smaller NoGo-N2 amplitudes under the smoking social background and smoking object background than they did under the neutral background; (3) relative to neutral and smoking object backgrounds, smokers displayed higher commission error rates, shorter reaction times, and larger NoGo-P3 amplitudes under smoking social background. ConclusionSmoking-related stimuli impair inhibitory control in smokers, especially when these stimuli are socially related.

The Efficacy and Cognitive Impact of Perampanel Monotherapy in Patients with Self-Limited Epilepsy with Centrotemporal Spikes: A Retrospective Analysis.

The third generation of antiepileptic medication (ASM) perampanel (PER), is mostly used as an add-on treatment for refractory epilepsy patients, and rarely used as a monotherapy. This study aims to observe the efficacy and assess the cognitive effects of PER monotherapy in patients with self-limited epilepsy with centrotemporal spikes (SeLECTS). Through screening, 86 patients who were first diagnosed with SeLECTS and treated with PER monotherapy were included in this study. All patients were followed up at least 12 months, and Evaluated the efficacy and safety of PER by observing the seizures of patients. At the same time, we used the P300 event-related potential (ERP) component and Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) to evaluate the cognitive changes in children before and after treatment with PER. Ten percent of the children experienced adverse effects, such as dizziness, gait instability, and irritability. The drug retention rate at the last follow-up was 98.83%. Further more, the P300 ERP component and WISC-IV tests were performed no significant difference before and 12 months after PER monotherapy in SeLECTS children. The third-generation of ASM PER monotherapy had a clear effect in children with SeLECTS. A small dose of PER can control seizures well and has no obvious effect on cognitive development.

Forensic Study on Objective Evaluation of Visual Acuity of Ametropia with the Event-related Potential P3.

In this study, we aimed to assess the characteristics of the P3 component from an event-related potential (ERP) that was induced by visual acuity (VA) processing. Furthermore, we sought to provide electrophysiological evidence for the objective evaluation of VA. We recruited 32 participants with myopia-related ametropia. They reported no other ocular diseases and had an uncorrected VA of 4.0 in both eyes. We used the block letter "E" at different visual angles and orientations as the graphic stimuli. The oddball paradigm, consisting of 4 modules, was used for ERP analysis. The standard stimuli of each module were identical, with a visual angle of 1°15'. The visual angles of the target stimuli were 1°15', 55', 24', and 15'. The VA test was performed on each eye separately for all participants, and all characteristics of the P3 component were analyzed. There was no significant difference in the P3 peak letencies between the target stimulation angle 1°15' group and the 55' group, or between the target stimulation angle 24' group and the 15' group. There was a significant difference in the P3 peak letencies between the target stimulation angle 1°15' group and the 24' group as well as the 15' group. There was a significant difference in the P3 peak letencies between the target stimulation angle 55' group and the 24' group as well as the 15' group. No significant differences were observed in the P3 amplitude between modules. In the oddball paradigm, P3 elicitation indicated a cognitive response to the target stimuli. These data showed that the characteristics of P3 can be used as an objective evaluation of VA.

Medial prefrontal transcranial alternating current stimulation for apathy in Huntington's disease

We investigated the effects of transcranial alternating current stimulation (tACS) targeted to the bilateral medial prefrontal cortex (mPFC) and administered at either delta or alpha frequencies, on brain activity and apathy in people with Huntington's disease (HD) (n = 17). Given the novelty of the protocol, neurotypical controls (n = 20) were also recruited. All participants underwent three 20-min sessions of tACS; one session at alpha frequency (Individualised Alpha Frequency (IAF), or 10 Hz when an IAF was not detected); one session at delta frequency (2 Hz); and a session of sham tACS. Participants completed the Monetary Incentive Delay (MID) task with simultaneous recording of EEG immediately before and after each tACS condition. The MID task presents participants with cues signalling potential monetary gains or losses that increase activity in key regions of the cortico-basal ganglia-thalamocortical networks, with dysfunction of the latter network being implicated in the pathophysiology of apathy. We used the P300 and Contingent Negative Variation (CNV) event-related potentials elicited during the MID task as markers of mPFC engagement. HD participants' CNV amplitude significantly increased in response to alpha-tACS, but not delta-tACS or sham. Neurotypical controls' P300 and CNV were not modulated by any of the tACS conditions, but they did demonstrate a significant decrease in post-target response times following alpha-tACS. We present this as preliminary evidence of the ability of alpha-tACS to modulate brain activity associated with apathy in HD.

Neural Indicators of Visual Andauditory Recognition of Imitative Words on Different De-Iconization Stages.

The research aims to reveal neural indicators of recognition for iconic words and the possible cross-modal multisensory integration behind this process. The goals of this research are twofold: (1) to register event-related potentials (ERP) in the brain in the process of visual and auditory recognition of Russian imitative words on different de-iconization stages; and (2) to establish whether differences in the brain activity arise while processing visual and auditory stimuli of different nature. Sound imitative (onomatopoeic, mimetic, and ideophonic) words are words with iconic correlation between form and meaning (iconicity being a relationship of resemblance). Russian adult participants (n = 110) were presented with 15 stimuli both visually and auditorily. The stimuli material was equally distributed into three groups according to the criterion of (historical) iconicity loss: five explicit sound imitative (SI) words, five implicit SI words and five non-SI words. It was established that there was no statistically significant difference between visually presented explicit or implicit SI words and non-SI words respectively. However, statistically significant differences were registered for auditorily presented explicit SI words in contrast to implicit SI words in the N400 ERP component, as well as implicit SI words in contrast to non-SI words in the P300 ERP component. We thoroughly analyzed the integrative brain activity in response to explicit IS words and compared it to that in response to implicit SI and non-SI words presented auditorily. The data yielded by this analysis showed the N400 ERP component was more prominent during the recognition process of the explicit SI words received from the central channels (specifically Cz). We assume that these results indicate a specific brain response associated with directed attention in the process of performing cognitive decision making tasks regarding explicit and implicit SI words presented auditorily. This may reflect a higher level of cognitive complexity in identifying this type of stimuli considering the experimental task challenges that may involve cross-modal integration process.

Study on clinical characteristics of event-related potential P300 in elderly schizophrenics and associated risk factors.

To investigate the clinical characteristics of event-related potential P300 in elderly schizophrenics with different levels of violence and the risk factors of severe violence. A total of 138 elderly schizophrenic patients from January 2020 to December 2021 in the First Hospital of Hebei Medical University were enrolled in this retrospective analysis. Based on the violence risk assessment, 61, 102, and 145 patients were divided into high-risk, medium-risk, and low-risk groups, respectively. Clinical characteristics, P300 latency, and P300 amplitude were compared among the three groups followed by a logistic regression analysis of elderly schizophrenics with severe violence. The latency of P300 in the high-risk group was higher than that in the low-risk group (p<.05). The P300 amplitude of patients in the high-risk group was significantly lower than that in the low-risk group (p<.05). Univariate logistic regression analysis showed that previous history of violence, delusion of persecution, P300 latency, and amplitude were independent influencing factors of severe violence in elderly schizophrenics (odds ratio [OR]: 0.022, 95% confidence interval [CI]: 0.007-0.067, p<.001; OR: 0.118, 95% CI: 0.043-1.763, p=.037; OR: 1.289, 95% CI: 1.142-1.673, p<.001; and OR: 0.049, 95% CI: 0.021-0.067, p<0.001, respectively). After adjusting gender, age, and other confounding factors, multivariate logistic regression analysis showed that delusion of persecution, P300 latency, and P300 amplitude were associated with severe violence in elderly schizophrenics (OR: 2.211, 95% CI: 0.061-4.067, p<.001; OR: 2.006, 95% CI: 1.421-2.721, p=.017; and OR: 0.067, 95% CI: 0.037-0.276; p<.001; respectively). The latency and amplitude of P300 can be used as effective neuroelectrophysiological indicators to evaluate the violence level of elderly schizophrenics. Delusion of persecution, P300 latency, and P300 amplitude were independent influencing factors of severe violence in elderly schizophrenics.

A spatial-temporal linear feature learning algorithm for P300-based brain-computer interfaces

Speller brain-computer interface (BCI) systems can help neuromuscular disorders patients write their thoughts by using the electroencephalogram (EEG) signals by just focusing on the speller tasks. For practical speller-based BCI systems, the P300 event-related brain potential is measured by using the EEG signal. In this paper, we design a robust machine-learning algorithm for P300 target detection. The novel spatial-temporal linear feature learning (STLFL) algorithm is proposed to extract high-level P300 features. The STLFL method is a modified linear discriminant analysis technique focusing on the spatial-temporal aspects of information extraction. A new P300 detection structure is then proposed based on the combination of the novel STLFL feature extraction and discriminative restricted Boltzmann machine (DRBM) for the classification approach (STLFL + DRBM). The effectiveness of the proposed technique is evaluated using two state-of-the-art P300 BCI datasets. Across the two available databases, we show that in terms of average target recognition accuracy and standard deviation values, the proposed STLFL + DRBM method outperforms traditional methods by 33.5, 78.5, 93.5, and 98.5% for 1, 5, 10, and 15 repetitions, respectively, in BCI competition III datasets II and by 71.3, 100, 100, and 100% for 1, 5, 10, and 15 repetitions, respectively, in BCI competition II datasets II and by 67.5 ± 4, 84.2 ± 2.5, 93.5 ± 1, 96.3 ± 1, and 98.4 ± 0.5% for rapid serial visual presentation (RSVP) based dataset in repetitions 1–5. The method has some advantages over the existing variants including its efficiency, robustness with a small number of training samples, and a high ability to create discriminative features between classes.

Клинические и нейрофизиологические корреляты когнитивных нарушений у пациентов с атеросклеротическим поражением сонных артерий

INTRODUCTION: Cognitive disorders often do not come to the fore in the interpretation of clinical manifestations in hemodynamically significant stenoses of brachiocephalic arteries. In this regard, the objectification of cognitive disorders based on a battery of tests, as well as of their neurophysiological correlates, is an important task of both angiology and neurology. Endogenous evoked potential P300 is a frequently used neurophysiological phenomenon characterizing the psychophysiological functions of perception, attention, and thinking. AIM: To study the dynamics of cognitive functions and their neurophysiological correlates in patients with hemodynamically significant carotid artery stenosis before and after carotid endarterectomy. MATERIALS AND METHODS: An open prospective study included 60 patients divided to two groups. Group A included 30 ‘symptomatic’ patients with a hemodynamically significant lesion (stenosis) of the internal carotid artery and a history of acute cerebrovascular accident. Group B included 30 ‘asymptomatic patients’ without a history of cerebrovascular events. Within the study, before surgery for carotid stenosis and 6 months after, the following parameters were assessed: cognitive status (according to the MMSE, FAB, MoCA, NIHSS scales), and also clinical and neurophysiological correlates of cognitive functions (P300 evoked potential). RESULTS: In the group of patients with neurological disorders (group A), a reliably greater number of errors (p = 0.048), as well as a decrease in the amplitude (p = 0.006) and increase in latency (p = 0.022) of P2 component of P300 cognitive evoked potential were determined. Based on the parameters of P300 event-related potential, a logit regression model was created that permitted to classify patients to the above-mentioned groups. The cluster analysis of dynamics of cognitive functions was additionally performed before and after surgery. In cluster 1, there were 45% of symptomatic patients, 55% of asymptomatic ones, in cluster 2 — 58% and 32%, respectively, no reliable differences were found (chi-square 0.58; p = 0.445). Cluster 1 was characterized by initially higher level of test performance with some increase in this parameter after surgery; Cluster 2 was characterized by a lower level of these parameters, with the greatest differences found in frontal assessment battery (FAB) characteristics. Reliable differences in the level of P300 were found only after surgery: the greatest differences were recorded in the amplitude of P2, P3, N2 components. CONCLUSION: The factor of cognitive impairment is a separate phenomenon, not closely related to focal neurological syndrome in patients with carotid atherosclerosis. An objective neurophysiological criterion for cognitive impairment in these patients is the endogenous evoked potential P300. With this, the greatest differences between the neurophysiological correlates of cognitive disorders are determined 6 months after the operation for carotid stenosis.

Immediate effects and duration of a short and single application of transcutaneous auricular vagus nerve stimulation on P300 event related potential.

Transcutaneous auricular vagus nerve stimulation (taVNS) is a neuromodulatory technique that stimulates the auricular branch of the vagus nerve. The modulation of the locus coeruleus-norepinephrine (LC-NE) network is one of the potential working mechanisms of this method. Our aims were 1-to investigate if short and single applications of taVNS can modulate the P300 cognitive event-related potential (ERP) as an indirect marker that reflects NE brain activation under control of the LC, and 2-to evaluate the duration of these changes. 20 healthy volunteers executed an auditory oddball paradigm to obtain P300 and reaction time (RT) values. Then a 7 min active or sham taVNS period was initiated and simultaneously a new P300 paradigm was performed. We successively repeated the paradigm on 4 occasions with different time intervals up to 56 min after the stimulation onset. During active taVNS an immediate and significant effect of increasing the amplitude and reducing the latency of P300, as well as a shortening in the RT was observed. This effect was prolonged in time up to 28 min. The values then returned to pre-stimulation levels. Sham stimulation did not generate changes. Our results, demonstrate differential facilitating effects in a concrete time window after taVNS. Literature about the modulatory effect of taVNS over P300 ERP shows a wide spread of results. There is not a standardized system for taVNS and currently the great heterogeneity of stimulation approaches concerning targets and parameters, make it difficult to obtain conclusions about this relationship. Our study was designed optimizing several stimulation settings, such as a customized earbud stimulator, enlarged stimulating surface, simultaneous stimulation over the cymba and cavum conchae, a Delayed Biphasic Pulse Burst and current controlled stimulation that adjusted the output voltage and guaranteed the administration of a preset electrical dose. Under our stimulation conditions, targeting vagal nerve fibers via taVNS modulates the P300 in healthy participants. The optimal settings of modulatory function of taVNS on P300, and their interdependency is insufficiently studied in the literature, but our data provides several easily optimizable parameters, that will produce more robust results in future.

Perception of self-generated and externally-generated visual stimuli: Evidence from EEG and behavior.

Efference copy-based forward model mechanisms may help us to distinguish between self-generated and externally-generated sensory consequences. Previous studies have shown that self-initiation modulates neural and perceptual responses to identical stimulation. For example, event-related potentials (ERPs) elicited by tones that follow a button press are reduced in amplitude relative to ERPs elicited by passively attended tones. However, previous EEG studies investigating visual stimuli in this context are rare, provide inconclusive results, and lack adequate control conditions with passive movements. Furthermore, although self-initiation is known to modulate behavioral responses, it is not known whether differences in the amplitude of ERPs also reflect differences in perception of sensory outcomes. In this study, we presented to participants visual stimuli consisting of gray discs following either active button presses, or passive button presses, in which an electromagnet moved the participant's finger. Two discs presented visually 500-1250 ms apart followed each button press, and participants judged which of the two was more intense. Early components of the primary visual response (N1 and P2) over the occipital electrodes were suppressed in the active condition. Interestingly, suppression in the intensity judgment task was only correlated with suppression of the visual P2 component. These data support the notion of efference copy-based forward model predictions in the visual sensory modality, but especially later processes (P2) seem to be perceptually relevant. Taken together, the results challenge the assumption that N1 differences reflect perceptual suppression and emphasize the relevance of the P2 ERP component.

Uric acid is negatively associated with cognition in the first- episode of schizophrenia

BackgroundWe explored the relationship between levels of serum uric acid (UA) and cognitive impairment in people with schizophrenia to order to better protect and improve cognitive function in such patients. MethodsA uricase method evaluated serum UA levels in 82 individuals with first-episode schizophrenia and in 39 healthy controls. The Brief Psychiatric Rating Scale (BPRS) and the event-related potential P300 were used to assess the patient's psychiatric symptoms and cognitive functioning. The link between serum UA levels, BPRS scores, and P300 was investigated. ResultsPrior to treatment, serum UA levels and latency N3 in the study group were significantly higher than in the control group, whereas the amplitude P3 was considerably lower. After therapy, the study group's BPRS scores, serum UA levels, latency N3, and amplitude P3 were lower than before treatment. According to correlation analysis, serum UA levels in the pre-treatment study group significantly positively correlated with BPRS score and latency N3 but not amplitude P3. After therapy, serum UA levels were no longer substantially related to the BPRS score or amplitude P3 but strongly and positively correlated with latency N3. ConclusionsFirst-episode schizophrenia patients have higher serum UA levels than the general population which partly reflects poor cognitive performance. Improving patients’ cognitive function may be facilitated by lowering serum UA levels.

High-definition transcranial direct current stimulation over right dorsolateral prefrontal cortex differentially modulates inhibitory mechanisms for speech vs. limb movement.

Evidence suggests that planning and execution of speech and limb movement are subserved by common neural substrates. However, less is known about whether they are supported by a common inhibitory mechanism. P3 event-related potentials (ERPs) is a neural signature of motor inhibition, which are found to be generated by several brain regions including the right dorsolateral prefrontal cortex (rDLPFC). However, the relative contribution of rDLPFC to the P3 response associated with speech versus limb inhibition remains elusive. We investigated the contribution of rDLPFC to the P3 underlying speech versus limb movement inhibition. Twenty-one neurotypical adults received both cathodal and sham high-definition transcranial direct current stimulation (HD-tDCS) over rDLPFC. ERPs were subsequently recorded while subjects were performing speech and limb Go/No-Go tasks. Cathodal HD-tDCS decreased accuracy for speech versus limb No-Go. Both speech and limb No-Go elicited a similar topographical distribution of P3, with significantly larger amplitudes for speech versus limb at a frontocentral location following cathodal HD-tDCS. Moreover, results showed stronger activation in cingulate cortex and rDLPFC for speech versus limb No-Go following cathodal HD-tDCS. These results indicate (1) P3 is an ERP marker of amodal inhibitory mechanisms that support both speech and limb inhibition, (2) larger P3 for speech versus limb No-Go following cathodal HD-tDCS may reflect the recruitment of additional neural resources-particularly within rDLPFC and cingulate cortex-as compensatory mechanisms to counteract the temporary stimulation-induced decline in speech inhibitory process. These findings have translational implications for neurological conditions that concurrently affect speech and limb movement.

Effect of Cognitive Reserve on Physiological Measures of Cognitive Workload in Older Adults with Cognitive Impairments.

Cognitive reserve may protect against cognitive decline. This cross-sectional study investigated the association between cognitive reserve and physiological measures of cognitive workload in older adults with cognitive impairment. 29 older adults with cognitive impairment (age: 75±6, 11 (38%) women, MoCA: 20±7) and 19 with normal cognition (age: 74±6; 11 (58%) women; MoCA: 28±2) completed a working memory test of increasing task demand (0-, 1-, 2-back). Cognitive workload was indexed using amplitude and latency of the P3 event-related potential (ERP) at electrode sites Fz, Cz, and Pz, and changes in pupillary size, converted to an index of cognitive activity (ICA). The Cognitive Reserve Index questionnaire (CRIq) evaluated Education, Work Activity, and Leisure Time as a proxy of cognitive reserve. Linear mixed models evaluated the main effects of cognitive status, CRIq, and the interaction effect of CRIq by cognitive status on ERP and ICA. The interaction effect of CRIq total score by cognitive status on P3 ERP and ICA was not significant. However, higher CRIq total scores were associated with lower ICA (p = 0.03). The interaction effects of CRIq subscores showed that Work Activity affected P3 amplitude (p = 0.03) and ICA (p = 0.03) differently between older adults with and without cognitive impairments. Similarly, Education affected ICA (p = 0.02) differently between the two groups. No associations were observed between CRIq and P3 latency. Specific components of cognitive reserve affect cognitive workload and neural efficiency differently in older adults with and without cognitive impairments.

The auditory P2 differentiates self- from partner-produced sounds during joint action: Contributions of self-specific attenuation and temporal orienting of attention

Sensory attenuation of the auditory P2 event-related potential (ERP) has been shown to differentiate the sensory consequences of one's own from others' action in joint action contexts. However, recent evidence suggests that when people coordinate joint actions over time, temporal orienting of attention might simultaneously contribute to enhancing the auditory P2. The current study employed a joint tapping task in which partners produced tone sequences together to examine whether temporal orienting influences auditory ERP amplitudes during the time window of self-other differentiation. Our findings demonstrate that the combined requirements of coordinating with a partner toward a joint goal and immediately adjusting to the partner's tone timing enhance P2 amplitudes elicited by the partner's tone onsets. Furthermore, our findings replicate prior evidence for self-specific sensory attenuation of the auditory P2 in joint action, and additionally demonstrate that it occurs regardless of the coordination requirements between partners. Together, these findings provide evidence that temporal orienting and sensory attenuation both modulate the auditory P2 during joint action and suggest that both processes play a role in facilitating precise interpersonal coordination between partners.

High-intensity interval vs. continuous moderate-intensity aerobic exercise for improving neurotransmitter level and neurocognitive performance in individuals with Parkinson's disease

In individuals with Parkinson's disease (PD), cognitive impairments can cause their quality of life to deteriorate and aggravate their motor symptoms. No studies have yet explored the neurophysiological and neurobiochemical mechanisms of changes in cognitive processing underlying neuropsychological problems exhibited by this group. The current study aimed to investigate and compare the acute effects of high-intensity interval exercise (HIIE) and continuous moderate-intensity exercise (CMIE) on the neurocognitive performance and neurotransmitter levels of individuals with PD. In addition, the relationship between changes in neurocognitive performance and those in the peripheral dopamine level induced by HIIE and CMIE interventions were also examined. Using a within-subjects design, twenty-three participants with mild to moderate PD completed a single session of both HIIE and CMIE, as well as a session in a control condition (REST) in counterbalanced order. The neurocognitive indices of working memory [i.e., accuracy rate (AR), reaction time (RT), and latencies and amplitudes of N2 and P3 event-related potentials (ERPs)] were assessed. Blood samples were taken before and after the three intervention modes. During the working memory task, acute HIIE and acute CMIE brought about faster RTs and P3 ERP waves with higher amplitudes in individuals with PD. Furthermore, better ARs and a shorter N2 latency were associated with engaging in HIIE and CMIE, respectively. On the other hand, only the acute CMIE intervention was associated with significant increases in the plasma dopamine level. Finally, no significant correlation was obtained between changes in neurocognitive performance and those in the dopamine level which were assessed both before and after taking part in the interventions. For individuals with mild to moderate PD, acute HIIE and CMIE proved to be tolerable, safe, and effective modes of aerobic exercise. These types of exercise are well-suited to be practiced at home and in a community setting in order to decrease the risk of cognitive impairment in general and more specifically the risk of developing dementia as a comorbidity of PD. However, the acute benefits underlying the two dynamic forms of exercise appear to be intensity-dependent in PD.