Individual differences in working memory and general intelligence indexed by P200 and P300: A latent variable model

Neural correlates of intelligence: ERP Components of temporary storage predict fluid intelligence over and above those of executive functions

Previous research has revealed that individuals with different levels of intelligence exhibit distinct patterns of event-related potentials (ERPs) related to executive functions and temporary storage. However, there is a lack of studies investigating the relative contributions of these ERPs in predicting individual differences in fluid intelligence. This study aims to examine the extent to which ERPs associated with executive functions and temporary storage can predict individual differences in fluid intelligence. Special attention is given to determining whether electrophysiological activities of temporary storage can predict fluid intelligence after accounting for executive functions, and vice versa. Both executive attention and temporary storage were measured by two experimental tasks, while electroencephalographic data were collected simultaneously. Fluid intelligence was assessed by two established tests. To address previous inconsistencies due to small sample sizes, a relatively large sample of young adults (N = 136) was recruited. The results revealed that participants with lower fluid intelligence displayed larger P3 amplitudes in the executive functions and temporary storage tasks compared to those with higher fluid intelligence. Additionally, the amplitudes of frontal and parietal P3s elicited by both executive functions and temporary storage significantly predicted fluid intelligence. Interestingly, the frontal and parietal P3s associated with temporary storage predicted fluid intelligence beyond the contributions of executive functions, supporting the storage account of individual differences in fluid intelligence. This study provides an original and fresh understanding of how executive functions and temporary storage contribute to fluid intelligence, offering new insights into the neurocognitive mechanisms underlying intelligence.

The influence of perceptual and semantic chunking on the neural mechanism of remote association

Studies on remote association tests (RATs) have mainly focused on cognitive processes involved in searching for remote associations. However, factors affecting these search processes and remote associations remain unclear. In order to address this issue, this study compared non-chunking condition (e.g., "//") with perceptual chunking (two red color characters in the three-character item "//") and semantic chunking (high-frequency word-pair in the item; e.g., "//", "," literally "philosophy") conditions in the Chinese Remote Association Test (CRAT). The behavioral results on the CRAT found that the semantic ones resulted in significantly lower successful solving rates and longer response times than the other two conditions. The event-related potential (ERP) results showed that in contrast to the perceptual-chunking and the non-chunking condition, the semantic-chunking elicited enhanced P200, which might be related to the intuitive awareness of the mental fixation. However, relative to the non-chunking condition, the two chunking conditions evoked increased N400 and late positive component (LPC), indexing the late reflection and implementation of cognitive control. Our results suggest that it is the early awareness of the semantic chunk, rather than the general cognitive control process involved in representing and solving the semantically and perceptually chunk-induced interferences, that critically determines the final solving of RATs.

Cognitive Functions following Trigeminal Neuromodulation

Vast scientific effort in recent years have been focused on the search for effective and safe treatments for cognitive decline. In this regard, non-invasive neuromodulation has gained increasing attention for its reported effectiveness in promoting the recovery of multiple cognitive domains after central nervous system damage. In this short review, we discuss the available evidence supporting a possible cognitive effect of trigeminal nerve stimulation (TNS). In particular, we ask that, while TNS has been widely and successfully used in the treatment of various neuropsychiatric conditions, as far as research in the cognitive field is concerned, where does TNS stand? The trigeminal nerve is the largest cranial nerve, conveying the sensory information from the face to the trigeminal sensory nuclei, and from there to the thalamus and up to the somatosensory cortex. On these bases, a bottom-up mechanism has been proposed, positing that TNS-induced modulation of the brainstem noradrenergic system may affect the function of the brain networks involved in cognition. Nevertheless, despite the promising theories, to date, the use of TNS for cognitive empowering and/or cognitive decline treatment has several challenges ahead of it, mainly due to little uniformity of the stimulation protocols. However, as the field continues to grow, standardization of practice will allow for data comparisons across studies, leading to optimized protocols targeting specific brain circuitries, which may, in turn, influence cognition in a designed manner.

Short-term transcutaneous trigeminal nerve stimulation does not affect visual oddball task and paired-click paradigm ERP responses in healthy volunteers

Recent research suggests that transcutaneous trigeminal nerve stimulation (TNS) may positively affect cognitive function. However, no clear-cut evidence is available yet, since the majority of it derives from clinical studies, and the few data on healthy subjects show inconsistent results. In this study, we report the effects of short-term TNS on event-related potentials (ERP) recorded during the administration of a simple visual oddball task and a paired-click paradigm, both considered useful for studying brain information processing functions. Thirty-two healthy subjects underwent EEG recording before and after 20 min of sham- or real-TNS, delivered bilaterally to the infraorbital nerve. The amplitude and latency of P200 and P300 waves in the simple visual oddball task and P50, N100 and P200 waves in the paired-click paradigm were measured before and after treatment. Our results show that short-term TNS did not alter any of the ERP parameters measured, suggesting that in healthy subjects, short-term TNS may not affect brain processes involved in cognitive functions such as pre-attentional processes, early allocation of attention and immediate memory. The perspective of having an effective, non-pharmacological, non-invasive, and safe treatment option for cognitive decline is particularly appealing; therefore, more research on the positive effects on cognition of TNS is definitely needed.

Global Functional Connectivity at Rest Is Associated with Attention: An Arterial Spin Labeling Study

Neural markers of attention, including those frequently linked to the event-related potential P3 (P300) or P3b component, vary widely within and across participants. Understanding the neural mechanisms of attention that contribute to the P3 is crucial for better understanding attention-related brain disorders. All ten participants were scanned twice with a resting-state PCASL perfusion MRI and an ERP with a visual oddball task to measure brain resting-state functional connectivity (rsFC) and P3 parameters (P3 amplitudes and P3 latencies). Global rsFC (average rsFC across the entire brain) was associated with both P3 amplitudes (r = 0.57, p = 0.011) and P3 onset latencies (r = -0.56, p = 0.012). The observed P3 parameters were correlated with predicted P3 amplitude from the global rsFC (amplitude: r = +0.48, p = 0.037; latency: r = +0.40, p = 0.088) but not correlated with the rsFC over the most significant individual edge. P3 onset latency was primarily related to long-range connections between the prefrontal and parietal/limbic regions, while P3 amplitudes were related to connections between prefrontal and parietal/occipital, between sensorimotor and subcortical, and between limbic/subcortical and parietal/occipital regions. These results demonstrated the power of resting-state PCASL and P3 correlation with brain global functional connectivity.

Evidence in Support of Analogical Reasoning Improvements with Executive Attention Intervention in Healthy Young Adults

Analogical reasoning improvement is important in educational outcome improvement. Inspired by recent ideas and evidence, we applied anti-saccade task training as an executive attention intervention and tested whether it could improve analogical reasoning performance. A serial-task paradigm was applied where participants performed an anti-saccade followed by an analogical reasoning task including a perception condition. The experimental group finished the anti-saccade task in which the ratio of anti-saccade trials to pro-saccade trials was 5:1 while the counterpart was 1:1 in the active control group. Also, a blank control group was established where participants merely finished the analogical reasoning task. Event-related electroencephalographic (EEG) data were recorded when participants were performing the executive attention and analogical reasoning tasks. In addition, their resting state EEG was collected before and after the executive attention intervention. Behaviorally, the experimental group reacted significantly faster than the other two groups in analogical reasoning but not in perception. At the neural level, in the experimental group alone, the anti-saccade trials elicited a smaller N2 than pro-saccade trials and the resting alpha power was improved after executive attention intervention. No significant difference in P2 was found between the two groups in analogical reasoning or perception but the experimental group showed a larger late positive component than the active control group in analogical reasoning. We also found that the late positive component mediated the relationship between the N2 of anti-saccade trials and analogical reasoning reaction times in the experimental group. We further discussed the role of executive attention in the analogical reasoning process, which may pave the way for the future reliable improvement of fluid intelligence.

Event-related potential and neuropsychological function in depressed older adults with cognitive impairment: A correlational study

Background

Increased depression severity has been linked to cognitive functioning impairment, such as deficits in episodic memory and executive function, causing difficulties in planning strategies, which ultimately lead to impaired decision-making functions. There are number of ways to assess cognitive functions, two most important and routinely done tests are neuropsychological test battery (NBT) and event-related potentials (ERPs).

Objective

This study examines the relationship between conventional neuropsychological tests assessing various cognitive domains and an ERP-P300 in depressed older adults.

Methods

Forty-six depressed elderly subjects participated in the study. NBT (Pennsylvania's Penn Computerized Neurocognitive Battery [Penn CNP]) assessing attention, episodic memory, working memory, social cognition, complex cognition, and sensorimotor speed and ERP-P300 (amplitude μV and latency ms) was recorded using an auditory oddball paradigm.

Results

Correlation test was run and Pearson's analysis and revealed that there was a negative statistically significant linear correlation between working memory on NBT and P300 wave amplitude on ERP-P300 (r = -0.34, P = 0.021) and between complex cognition on NBT and P300 wave latency on ERP-P300 (r = -0.47, P < 0.001). No correlation was found between other tests on NBT and ERP-P300 wave characteristics. Further, the regression analysis (R ²) revealed that P300 amplitude was found to significantly predict the working memory (R ² = 0.116) and P300 latency was found to significantly predict the complex cognition (R ² = 0.224).

Conclusion

Therefore, we conclude that neurophysiological measurements cannot be substituted by neuropsychological tests or vice versa; rather, higher brain functions should be estimated by both of the methods.

Fatigue-Related Effects in the Process of Task Interruption on Working Memory

Interruption generally has a negative effect on performance by affecting working memory (WM). However, the neural mechanism of interruption has yet to be understood clearly, and previous studies have largely ignored the role of fatigue state. To address these issues, the present study explores the behavioral and electrophysiological effects of interruption on WM performance using electroencephalography (EEG) data. The moderating effect of fatigue is also explored. The participants performed spatial 2-back tasks with math task interruption, suspension interruption, and non-interruption under different fatigue states. The results show that interruption led to increased alpha activity and P300 amplitude, indicating inhibitory control to interference from irrelevant information. Analysis of P200 amplitude revealed that interruption affected attentional reallocation when resuming the primary task. Increased theta power indicated an increased demand for information maintenance during the interruption. A speeding-up effect was discovered after interruption; however, fatigue impaired cognitive ability and further exacerbated the negative effects of interruption on WM and behavioral performance. These findings contribute to a better understanding of cognitive activity during the interruption and of the interaction with fatigue, and provide further support for the theory of memory for goals (MFG).

Neurophysiological markers of prospective memory and working memory in typical ageing and mild cognitive impairment

OBJECTIVE

Prospective memory (PM) -the memory of delayed intentions- is impacted by age-related cognitive decline. The current event-related potential study investigates neural mechanisms underpinning typical and atypical (Mild Cognitive Impairment, MCI) age-related decline in PM.

METHODS

Young adults (YA, n = 30, age = 24.7, female n = 13), healthy older adults (OA, n = 39, age = 72.87, female n = 24) and older adults with MCI (n = 27, age = 77.54, female n = 12) performed two event-based PM tasks (perceptual, conceptual) superimposed on an ongoing working memory task. Electroencephalographic data was recorded from 128 electrodes. Groups were compared for P2 (higher order perceptual processing), N300/frontal positivity (cue detection), the parietal positivity (retrieval), reorienting negativity (RON; attention shifting).

RESULTS

Participants with MCI had poorer performance (ongoing working memory task, conceptual PM), lower P2 amplitudes, and delayed RON (particularly for perceptual PM) than YA and OA. MCI had lower parietal positivity relative to YA only. YA had earlier latencies for the parietal positivity than MCI and OA, and lower amplitudes for N300 (than OA) and frontal positivity (than OA and MCI).

CONCLUSIONS

Impaired attention and working memory may underpin PM deficits in MCI.

SIGNIFICANCE

This is the first study to document the role of RON in PM and to investigate neurophysiological mechanisms underpinning PM in MCI.

Interpretability of Spatiotemporal Dynamics of the Brain Processes Followed by Mindfulness Intervention in a Brain-Inspired Spiking Neural Network Architecture

Mindfulness training is associated with improvements in psychological wellbeing and cognition, yet the specific underlying neurophysiological mechanisms underpinning these changes are uncertain. This study uses a novel brain-inspired artificial neural network to investigate the effect of mindfulness training on electroencephalographic function. Participants completed a 4-tone auditory oddball task (that included targets and physically similar distractors) at three assessment time points. In Group A (n = 10), these tasks were given immediately prior to 6-week mindfulness training, immediately after training and at a 3-week follow-up; in Group B (n = 10), these were during an intervention waitlist period (3 weeks prior to training), pre-mindfulness training and post-mindfulness training. Using a spiking neural network (SNN) model, we evaluated concurrent neural patterns generated across space and time from features of electroencephalographic data capturing the neural dynamics associated with the event-related potential (ERP). This technique capitalises on the temporal dynamics of the shifts in polarity throughout the ERP and spatially across electrodes. Findings support anteriorisation of connection weights in response to distractors relative to target stimuli. Right frontal connection weights to distractors were associated with trait mindfulness (positively) and depression (inversely). Moreover, mindfulness training was associated with an increase in connection weights to targets (bilateral frontal, left frontocentral, and temporal regions only) and distractors. SNN models were superior to other machine learning methods in the classification of brain states as a function of mindfulness training. Findings suggest SNN models can provide useful information that differentiates brain states based on distinct task demands and stimuli, as well as changes in brain states as a function of psychological intervention.

Can Working Memory Task-Related EEG Biomarkers Measure Fluid Intelligence and Predict Academic Achievement in Healthy Children?

Background

Educational psychology research has linked fluid intelligence (Gf) with working memory (WM), but it is still dubious whether electroencephalography (EEG) markers robustly indicate Gf. This study addresses this issue and notes the relationship between WM task-related EEG markers with Gf and academic performance.

Method

A sample of 62 healthy children between the ages of 9 and 12 years was selected to perform three tasks: (1) Raven’s Standard Progressive Matrices (RSPM) test to assess Gf; (2) 2-back task to assess central executive system (CES); and (3) delayed match-to-sample task to assess short-term storage. These subjects were divided into high ability (HA) and low ability (LA) groups based on their RSPM scores. Support vector machine and logistic regression were used to train the EEG candidate indicators. A multiple regression was used to predict children’s academic performance using P3 amplitude, P2 latency, and θ-ERS.

Results

Behavioral results demonstrated that the correct rate of the HA group is higher than that of the LA group. The event-related potential results of the 2-back task showed that the P3 amplitude of the HA group was relatively larger and that the P2 latency was shorter than that observed in the LA group. For the delayed matching to sample task, the θ-ERS of the LA group was higher than that of the HA group. However, the area under the curve of these three indicators for Gf was < 0.75 for each and < 0.85 for the combined indicators. In predicting academic performance, only P3 amplitude showed a significant effect.

Conclusion

These results challenge previous findings, which reported that P3, P2, or theta power might be used in standard psychometric tests to assess an individual’s intelligence.