Individuals with depression experience more negative imagery and less vivid positive imagery, and the late positive potential (LPP) is considered as a viable biomarker for negative attentional and memory biases in depression; however, the LPP response to emotional imagery in depressed individuals remains unclear. This study aims to investigate neural response to emotional imagery in depressed individuals. ERPs were recorded from 40 depressed participants and 44 healthy controls during the encoding-imagery task. Depressed participants scored significantly lower in the valence rating of sad and neutral imagery compared to healthy participants. Importantly, the LPP amplitudes to sad imagery in depressed participants were significantly larger than healthy controls, particularly in the middle (800-1,400 ms) and late time windows(1,400-2,000 ms). Furthermore, depressed individuals exhibited significantly higher LPP amplitudes for sad imagery compared to happy imagery, whereas healthy participants showed the opposite pattern. The present study provides evidence that depressed individuals display abnormal electrophysiological reactivity to sad imagery, which offers a new perspective for understanding the mechanisms underlying depression.

Anxiety is a common psychological disorder associated with affective disorders and associated with other mental disorders, with depression being the most common comorbidity. Few studies have examined the neural mechanisms underlying anxiety after controlling for depressive symptoms. This study aimed to explore whether there are differences in cortical activation in anxiety patients with different severity whose depressive symptoms is normal. In current study, depression levels were normal for 366 subjects—139 healthy subjects, 117 with mild anxiety, and 110 with major anxiety. The Hospital Anxiety and Depression Scale (HADS) and a verbal fluency task (VFT) tested subjects’ anxiety and depression and cognitive function, respectively. A 53-channel guided near-infrared spectroscopic imaging technology (fNIRS) detected the concentration of oxyhemoglobin (oxy-Hb). Correlation analysis between anxiety severity and oxy-Hb concentration in the brain cortex was performed, as well as ANOVA analysis of oxy-Hb concentration among the three anxiety severity groups. Results showed that anxiety severity was significantly and negatively correlated with oxy-Hb concentration in the left frontal eye field (lFEF) and in the right dorsolateral prefrontal area (rDLPFC). The oxy-Hb concentration in the lFEF and the rDLPFC were significantly lower in the major anxiety disorder group than that in the control group. This suggests that decreased cortical activity of lFEF and rDLPFC may be neural markers of anxiety symptoms after control depressive symptoms. Anxiety symptoms without depressive symptoms may be result from the dysfunction of cognitive control network (CCN) which includes lFEF and rDLPFC.

Introduction: The rating of perceived exertion (RPE) is a widely used method for monitoring the load during training, as it provides insight into the subjective intensity of effort experienced during exercises. Considering the role of brain in monitoring and perception of the effort, several studies explored the effect of transcranial direct current stimulation (tDCS) on RPE in different populations. The aim of current study is to review the studies investigated the effect of tDCS on RPE in three groups including healthy untrained people, physically active persons and athletes. Method: Nine databases were searched for papers assessing the effect of tDCS on RPE. The data of included studies were extracted and methodological quality examined using the risk of bias 2 (ROB2) tool. Thirty-three studies met the inclusion criteria. Results: According to the meta-analysis, active a-tDCS significantly decreased the RPE compared to the sham-stimulation. The a-tDCS could decrease the RPE when it was applied over M1 or DLPF. Regarding the measurement tool, Borg’s scale 6-20 and OMNI scale could show an improvement in RPE scale. Conclusion: A-tDCS is a promising technique that can decrease improve the RPE. M1 and DLPFC are suggested as the target area of stimulation. From the tools that measure the RPE, Borg’s RPE 6-20 and OMNI scale could better show the effect of a-tDCS.

Disorders marked by high levels of impulsivity and compulsivity have been linked to changes in performance monitoring, specifically the error-related negativity (ERN). We investigated the relationship between performance monitoring and individual differences in impulsivity and compulsivity. A total of 142 participants were recruited into four groups, each with different combinations of impulsivity and compulsivity, and they performed a flanker task to assess error-related brain activity. We defined error-related brain activity as ERN amplitude and theta power. Single trial regression was employed to analyze the amplitude differences between incorrect and correct trials within the ERN time window. The findings revealed that impulsivity, compulsivity and different measures of response processing exhibited distinct interactions, which were influenced by the configuration of impulsivity and compulsivity, but also depending on the measure of response processing. Specifically, high compulsivity predicted larger ERN amplitudes in individuals with low impulsivity, whereas high impulsivity had no effect on ERN amplitude in individuals with low compulsivity. Furthermore, when both impulsivity and compulsivity were high, no increase in ERN amplitude was observed; instead, there was a reduced difference between incorrect and correct trials. No significant differences were found for theta power. While the association between error-related brain activity and transdiagnostic markers or psychopathology may be smaller than generally assumed, considering the interaction between different transdiagnostic markers and their facets can enhance our understanding of the complex associations that arise during the investigation of neural correlates of performance monitoring, specifically the ERN.

The human brain is postulated to function as a prediction machine, constantly comparing incoming sensory input to predictions based on past experiences. When an event contradicts these predictions, it results in a prediction error (PE), which has been shown to enhance subsequent memory. However, the neural mechanisms underlying the influence of PE on subsequent memory remain unclear. This study investigated the electrophysiological correlates during encoding and retrieval of events eliciting PE. We employed a statistical learning task in which participants were presented with pairs of objects in sequence. Subsequently, while recording electroencephalography (EEG), we introduced PE by replacing the second object of each pair with new objects and we then tested the participants’ memory. Behaviorally, PE did not enhance memory. During retrieval, we observed higher amplitudes of the posterior recollection component for violation items that were remembered compared to those that were forgotten. In contrast, no evidence for the presence of the frontal negative familiarity component was found. These results suggest that recollection, but not familiarity, plays a crucial role in the interplay between PE and memory. Contrary to our hypothesis, we did not observe a relationship between PE and the P3 component during encoding. In conclusion, our study contributes to the growing body of knowledge concerning the intricate relationship between PE and episodic memory. It sheds light on the underlying neural mechanisms involved and emphasizes the importance of recollection in this context.

This study aimed to explore the neural mechanism underlying high-altitude (HA) adaptation and deadaptation on perceptual processes in lowlanders. Eighteen healthy lowlanders were administered a facial S1-S2 matching task that included incomplete face (S1) and complete face (S2) photographs, combined with ERP technology. Participants were tested shortly before they went to HA at sea level (Test 1), twenty-five days after entering HA (Test 2), one week (Test 3) and one month (Test 4) after returning to lowlands. Compared with sea level baseline, shorter latencies of P1 and N170 and larger amplitudes of complete face N170 were found in HA. After returning to sea level, compared with HA, the amplitude of the incomplete face P1 was smaller after one week and the complete face was smaller after one month. The right hemisphere N170 amplitude was larger after entering HA and one week after returning to sea level compared to baseline, but it returned to baseline after one month. Taken together, the current findings suggest that HA adaptation increases visual cortex excitation to accelerate perceptual processing. More mental resources are recruited during the configural encoding stage of complete faces after HA exposure. The perceptual processes affected by HA exposure is reversible after returning to sea level, but the low-level processing stage is different between incomplete and complete faces due to neural compensation mechanisms. The configural encoding stage in the right hemisphere is affected by HA exposure and requires more than one week but less than one month to recover to baseline

Background: In applied psychophysiology, bootstrapping procedures are often used to classify individuals into one of two or more independent states (e.g., high risk vs low risk). Although the number of iterations required for a reliable bootstrap test is not universally agreed upon, some research (Rosenfeld et al., 2017b) suggests that 100 iterations is a sufficient number to obtain reliable results when analyzing P300 from a concealed information test. However, no study to-date has evaluated the diagnostic consistency of the 100 iterations test across repeated examinations. Methods: We evaluated the precision of the 100 iteration test by repeating the test 100 times per participant in a sample of 81 participants. The test was designed to classify participants as either knowledgeable or not knowledgeable of critical information related to a mock crime. Results: We found that the test provided variable classifications in approximately a quarter of our sample (n = 19/81 or 23%), specifically when a participant’s score presented near the diagnostic cutpoint. Moreover, the test’s diagnostic results varied by as much as +/-15%, in certain cases. Conclusion: Although the test provided reliable results for the majority of our sample, this was not true for a notable number of cases. We recommend that researchers report the variability of their diagnostic metrics and integrate this variability when classifying individuals. We discuss several simple examples of how to take variability into account when making classifications, such as by calculating the probability of one classification state over another given the data.

Transcranial pulsed current stimulation (tPCS) is a promising non-invasive brain stimulation technique that has gained considerable attention in recent years. The purpose of this review is to provide an overview of the existing literature on tPCS, examine the scope and nature of previous research, investigate its underlying mechanisms, and identify gaps in the literature. A search of online databases resulted in 36 published tPCS studies from inception until May 2023. These studies were categorized into three groups: human studies on healthy individuals, patient studies with pathological conditions, and animal studies. The findings suggest that tPCS has the potential to modulate brain excitability by entraining neural oscillations and utilizing stochastic resonance. However, the mechanisms underlying the effects of tPCS are not yet fully understood and require further investigation. Furthermore, the included studies indicate that tPCS may have therapeutic potential for neurological diseases. However, before tPCS can be applied in clinical settings, a better understanding of its mechanisms is crucial. In this regard, the tPCS studies were categorized into four types of research: basic, strategic, applied, and experimental research, to identify the nature of the literature and gaps. Analysis of these categories revealed that tPCS, with its diverse parameters, effects, and mechanisms, presents a wide range of research opportunities for future investigations.

While historically confined to isolated research laboratories, electroencephalography (EEG) paradigms can finally be used in studies involving walking and other complex behaviors. This transition from isolated/immobile to unstructured mobile research can open new doors to understanding attentional processes as they occur naturally. However, there are current limitations in mobile EEG that must be overcome to achieve great quality signals. We examine the feasibility of mobile paradigms, including ecological validity, artifact correction techniques, and methodological considerations. We review several mobile studies related to attentional demands. This includes the replication of robust effects like the P3 in mobile paradigms in our lab, studies using walking, cycling, and dual tasking to study attention. We discuss how the mobile approach compliments traditional laboratory paradigms while it can add new dimensions to cognitive and attentional research. We discuss promising applications of portable EEG in workplace safety and other areas including road safety, rehabilitation medicine, and brain-computer interfaces.

In behavioural and neurophysiological pain studies, multiple types of calibration methods are used to quantify the individual pain stimuli. Often studies lack calibration procedure implementation, have a vague protocol description, do not provide quality quantification, and omit required control for gender pain differences, hampering study repetition and interexperimental comparisons. Moreover, typical calibration procedures require a high number of stimulations which may cause participants’ discomfort and stimuli habituation. To overcome those shortcomings, we present an automatic calibration procedure with a novel stimuli estimation method for intra epidermal stimulation adjusted to the magnetoencephalography environment. We provide an in-depth data analysis of the collected self-reports from seventy healthy volunteers (37 males) and propose a method based on a dynamic truncated linear regression model (tLRM). We compare its estimates for the sensation (t), and pain (T) thresholds, as well as for the mid-pain stimulation (MP), with those calculated using a traditional estimation method and standard linear regression models. Compared to the other methods, tLRM exhibits higher R2 and requires 36% fewer stimuli application and has significantly higher t and lower T and MP intensities. Regarding sex differences, t and T were found to be lower for females compared to males, regardless of the estimation method. The proposed tLRM method quantifies the calibration procedure quality, minimizes its duration and invasiveness, as well as provides validation of linearity between stimuli intensity and subjective scores, making it an enabling technique for further studies. Moreover, our results highlight the importance of control for gender in pain studies

A document by Nadia Paraskevoudi. Click on the document to view its contents.

A document by Yin-Hua Chen. Click on the document to view its contents.

Exposure to stress can have significant, negative consequences on long-term health. Among potentially modifiable targets for promoting more adaptive stress responses, executive functioning has emerged as a promising candidate. These functions may be involved in limiting excessive stress reactivity when exposed to an acute stressor, while also promoting faster recovery (i.e., return to baseline). Fewer studies have been conducted to date on the role of executive functioning in acute stress – especially with a focus on its distinct facets (e.g., inhibition, flexibility, working memory, and updating). Moreover, there is a need for research focused on potential cognitive and behavioral mediators explaining the relationship between executive functioning and stress responses. Thus, the current study sought to examine the extent to which executive functioning facets may play a beneficial role in acute stress reactivity and recovery. Furthermore, we will examine the mediational role of cognitive appraisals, repetitive negative thinking, and emotion regulation. The findings may shed light on existing cognition-stress pathways that promote more adaptive acute stress responses.

Averaging multiple event-related potential (ERP) segments distorts the brain’s response to a stimulus given the false assumptions that the ERP signal is invariant and hidden by background noise. Our Single Trial Peaks (STP) procedure measures amplitude and latency of multiple peaks in each segment based on the peak latencies of the individual’s averaged ERP. This study examined correct trial data from 70 adults performing two repetitions of a speeded visual flanker task. STP peak data (P1, N1, P2, N2, and P3) were compared to single-trial averaged voltage in time windows (STW) and peaks of averaged ERPs. Results indicated that the STP approach had higher split-half reliability (odd-even, r =.70-.96) and test-retest reliability (r =.66-.97) than the STW approach. The mean signal/noise ratios for the amplitude measures for the STP ranged from 1.62 to 2.9 and were larger than the STW approach, although averaged ERPs had higher ratios than both. Coefficients of variation (CV) for the STP and STW approaches were similar, and both had smaller CVs than averaged ERPs. The validity of the STP approach was determined by regression analyses where mean trial-level peak amplitude, SDs across trials for amplitude and latency, and noise accounted for a significant amount of variance in corresponding peaks of the averaged ERPs (R2 =.73-.95). Curve fitting analyses showed nonlinear systematic patterns in amplitude over trials similar to changes in response time. These results support the validity of the STP approach which can be used to investigate systematic changes of brain activity across trial.