Increasing Task Difficulty Research Articles

Deviant sound frequency and time stimuli in auditory oddball tasks reveal persistent aberrant brain activity in patients with psychosis and symptomatic remission.

The detection of rare or deviant stimuli shares common brain circuits involved in temporal processing and salience, critical for cognitive control. Disruption in these processes may contribute to the mechanisms of the disease and explain cognitive deficits observed in psychosis and related disorders. We designed a neuroimaging study, using oddball task-based functional sequences (fMRI) and diffusion tensor imaging (DTI), comparing healthy controls (HC, n=14, 7 females) and patients with stable psychosis (PSY, n=20, 10 females). The PSY individuals had schizophrenia or bipolar disorder diagnosis (ICD-10), meeting symptom remission criteria in the last 6 months. Two variants of the auditory oddball paradigm were employed, focusing on sound frequency (SF) and time discrimination (TD) tasks, adapted for fMRI. We used a general linear model to analyze fMRI data and a random effects model for group analysis, complemented by an exploratory statistical agnostic mapping analysis. DTI data were processed using FSL (FMRIB Software Library) and TBSS (Tract Based Spatial Statistics). Distinct activation patterns between groups were observed, with increased brain activity in PSY in TD and SF oddball tasks. In response to increased task difficulty, HC predominantly activated cerebellar regions, whereas PSY relied more on frontal regions. Reduced fractional anisotropy in PSY correlated with lower performance scores in the MATRICS (Measurement and Treatment Research to Improve Cognition in Schizophrenia) Consensus Cognitive Battery (MCCB). The study underscores aberrant brain activity and white matter deficits in stable psychosis patients, highlighting distinct responses to cognitive challenges compared to HC. These findings may support the hypothesis of cognitive dysmetria as a potential underlying mechanism in psychosis and highlight future therapeutic strategies, including non-invasive brain stimulation techniques.

Information-seeking in mice (Mus musculus) during visual discrimination: study using a distractor elimination paradigm

Some animals seek information to solve problems when they do not know the answer. Information-seeking behavior has become a key focus in studies of animal metacognition, providing insights into how animals monitor their own knowledge states. This behavior is thought to be a form of metacognitive control. Nevertheless, research on such metacognitive control has been biased toward specific taxa, such as primates, and has not been conducted in rodents, which are the most common experimental animals. This study examined whether mice exhibit information-seeking behavior during two visual discrimination tasks and what factors influence this behavior. We trained mice to discriminate between stimuli differing in luminance or orientation, with more minor differences increasing task difficulty. An information-seeking option was introduced during these tasks, allowing mice to eliminate distractor stimuli and ensure a correct response. The results indicated that mice sought information more frequently during difficult discriminations than easier ones. However, subsequent generalization tests revealed that the mice relied on environmental cues to utilize the information-seeking option. These findings suggest that information-seeking behavior in mice may not solely reflect metacognitive processes, and further investigation is needed to explore alternative explanations.

The Importance of Frailty in Older Adults With Benign Paroxysmal Positioning Vertigo.

Even though Benign Paroxysmal Positioning Vertigo (BPPV) is one of the most reported vestibular disorders, its interaction with frailty and postural control in older adults is hardly or not investigated. Thirty-seven older adults (≥65years) with a diagnosis of BPPV (oaBPPV) (mean age 73.13 (4.8)) were compared to 22 age-, weight-, and height-matched controls (mean age 73.5 (4.5)). Modified Fried criteria were used to assess frailty. Postural control was assessed with the timed chair stand test, mini Balance Systems Evaluation test (mini-BESTest), a Clinical Test of Sensory Interaction on Balance (CTSIB), and 10-m walk test. Falls were inquired. The Dizziness Handicap Inventory, Falls Efficacy Scale, and 15-item Geriatric Depression Scale assessed dizziness-related handicap, fear of falling, and feelings of depression, respectively. To assess the importance of frailty, all variables were also compared between frail oaBPPV, robust oaBPPV, and robust controls in a sub-analysis. The significance level was set at α=0.05. oaBPPV reported significantly more multiple falls ( P =0.05) and difficulties to remain standing with increasing task difficulty of the CTSIB ( P =0.004). They were significantly more (pre-)frail compared to controls ( P <0.001). Moreover, frail oaBPPV had a significantly decreased reactive postural control ( P <0.001) and dynamic gait ( P <0.001). Their fear of falling ( P <0.001) and dizziness-related handicap ( P <0.001) were significantly higher compared to robust oaBPPV. oaBPPV were less healthy and more (pre-)frail compared to controls, impacting their daily functioning. Future research should investigate whether frailty and postural control were already decreased before the BPPV onset and if this recovers after treatment with repositioning maneuvers or if additional rehabilitation is necessary. Older adults with Benign Paroxysmal Positional Vertigo (BPPV) can present with an impaired sensory orientation, declined cognition, significantly more multiple falls, and (pre-)frailty compared to controls. Moreover, frail older adults with BPPV also had a significantly decreased reactive postural control and dynamic gait, and an increased odds of falling compared to robust controls. BPPV and frailty appear to be linked with each other, which cannot be ignored in future research and clinicians treating older adults with BPPV.

Assessment of embodied visuospatial perspective taking in augmented reality: insights from a reaction time task

Understanding another person’s visual perceptions is known as visuospatial perspective taking, with evidence to date demonstrating it is delineated across two levels, depending on how different that perspective is. Some strategies for visuospatial perspective taking have also been found to involve embodied cognition. However, the current generalisation of these findings is limited due to experimental setup and the use of computer monitors as the interface for experimental tasks. Augmented reality interfaces could possibly extend on the generalisation of these findings by situating virtual stimuli in the real environment, thus providing a higher degree of ecological validity and experimental standardisation. This study aimed to observe visuospatial perspective taking in augmented reality. This was achieved in participant experiments (N=24) using the Left-Right behavioural speeded decision task, which requires participants to discriminate between target objects relative to the perspective of an avatar. Angular disparity and posture congruence between the avatar and participant were manipulated between each trial to delineate between the two levels of visuospatial perspective taking and understand its potentially embodied nature. Although generalised linear mixed modeling indicated that angular disparity increased task difficulty, unexpectedly findings on posture congruence were less clear. Together, this suggests that visuospatial perspective taking in this study can be delineated across two levels. Further implications for embodied cognition and empathy research are discussed.

Driver Behavior Mechanisms and Conflict Risk Patterns in Tunnel-Interchange Connecting Sections: A Comprehensive Investigation Based on the Behavioral Adaptation Theory

Tunnel-interchange sections are characterized by complex driving tasks and frequent traffic conflicts, posing substantial challenges to overall safety and efficiency. Enhancing safety in these areas is crucial for the sustainability of traffic systems. This study applies behavior adaptation theory as an integrated framework to examine the impact of environmental stimuli on driving behavior and conflict risk in small-spaced sections. Through driving simulation, 19 observation indicators are collected, covering eye-tracking, heart rate, subjective workload, driving performance, and conflict risk. The analysis, using single-factor ranking (Shapley Additive Explanation), interaction effects (dependence plots), and multi-factor analysis (Structural Equation Modeling), demonstrates that driving workload and performance dominate the fully mediating effects between external factors and conflict risk. High-load environmental stimuli, such as narrow spacing (≤500 m) and overloaded signage information (&gt;6 units), significantly elevate drivers’ stress responses and impair visual acuity, thereby increasing task difficulty and conflict risk. Critical factors like saccade size, heart rate variability, lane deviation, and headway distance emerge as vital indicators for monitoring and supporting driving decisions. These findings provide valuable insights for the operational management of small-spacing sections and enhance the understanding of driving safety in these areas from a human factor perspective.

AI-assisted 3D analysis of grasping and reaching behavior of squirrel monkeys during recovery from cervical spinal cord injury

We have previously demonstrated that machine learning-based video analysis, conducted via DeepLabCut, is more sensitive for detecting subtle deficits in hand grasping behavior than traditional end-point performance assessments. This superiority was observed in a nonhuman primate (NHP) model of cervical spinal cord injury, specifically a dorsal column lesion (DCL). The current study aims to further characterize the kinematic aspects of the deficits in hand reaching, grasping, and retrieving behavior from a 3D perspective following a DCL. Squirrel monkeys were trained to retrieve sugar pellets from eight wells, which were located either on a flat plate or a raised tube with varying well depths. This setup was designed to require coordinated finger movements during the task. Immediately after the DCL, the animals exhibited measurable behavioral deficits. These were characterized by significant increases in grasping speed squared and trial completion time, markedly widened movement trajectories of individual fingers, and abnormalities in inter-finger distance and orientation. Increased task difficulty was associated with more pronounced behavioral deficits. By three months post-DCL, video-based measurements indicated no significant recovery, even though global end-point performance had returned to baseline levels. Our findings demonstrate that deprivation of tactile information results in impaired dexterous hand behavior involving coordinated finger movements, and the impairment is sustained for 20 weeks. This spinal cord injury (SCI) model, along with DeepLapCut analysis, provides a valuable platform for separately evaluating sensory and motor functions and their contributions to dexterous hand behavior and may be used for evaluating therapeutic interventions using more sensitive behavioral outcome readouts.

Support for the Time-Varying Drift Rate Model of Perceptual Discrimination in Dynamic and Static Noise Using Bayesian Model-Fitting Methodology.

The drift-diffusion model (DDM) is a common approach to understanding human decision making. It considers decision making as accumulation of evidence about visual stimuli until sufficient evidence is reached to make a decision (decision boundary). Recently, Smith and colleagues proposed an extension of DDM, the time-varying DDM (TV-DDM). Here, the standard simplification that evidence accumulation operates on a fully formed representation of perceptual information is replaced with a perceptual integration stage modulating evidence accumulation. They suggested that this model particularly captures decision making regarding stimuli with dynamic noise. We tested this new model in two studies by using Bayesian parameter estimation and model comparison with marginal likelihoods. The first study replicated Smith and colleagues' findings by utilizing the classical random-dot kinomatogram (RDK) task, which requires judging the motion direction of randomly moving dots (motion discrimination task). In the second study, we used a novel type of stimulus designed to be like RDKs but with randomized hue of stationary dots (color discrimination task). This study also found TV-DDM to be superior, suggesting that perceptual integration is also relevant for static noise possibly where integration over space is required. We also found support for within-trial changes in decision boundaries ("collapsing boundaries"). Interestingly, and in contrast to most studies, the boundaries increased with increasing task difficulty (amount of noise). Future studies will need to test this finding in a formal model.

Irreversibility in belief dynamics: Unraveling the link to cognitive effort.

The relationship between time irreversibility in neuronal dynamics and cognitive effort is a subject of growing interest in the scientific literature. Although correlations between proxies of both concepts have been experimentally observed, the underlying precise linkage between them remains elusive. Here we investigate the case of learning in decision-making tasks; we do so by introducing a thermodynamically grounded metric-inspired by Landauer's principle-which connects time-irreversible information processing to energy consumption. Equipped with this metric, we investigate the role of macroscopic time-reversal symmetry breaking in belief dynamics for the case of an agent with finite sensitivity while performing a static two-armed bandit task-a standard setup in cognitive neuroscience. To gain insights into the belief dynamics, we analogize it to the dynamics of an active particle subject to state-dependent noise and living in a two-dimensional space. This mapping allows an analytical description of learning-induced biases. We deeply explore the case of Q-learning with forgetting the nonchosen option. In this case, learning-induced risk aversion is formally equivalent to standard thermophoresis, i.e., the net motion towards low-temperature regions. Finally, we quantify the irreversibility of belief dynamics in the steady state for different bandit configurations, sensitivity levels, and exploitative behavior. We found a strong correlation in high-sensitivity learning between heightened irreversibility in belief dynamics and improved decision-making outcomes. Notably, as the task's difficulty increases, a greater degree of irreversibility in belief dynamics becomes necessary for having superior performances; this explicitly unravels a plausible connection between time irreversibility and cognitive effort. In conclusion, our investigation reveals that irreversibility in belief dynamics bridges out-of-equilibrium statistical physics concepts and cognitive neuroscience. In decision-making contexts, this perspective offers insights into the notion of cognitive effort, suggesting a potential mechanism driving the evolution of living systems toward out-of-equilibrium structures.

Perceptions of task difficulty predict cognitive effort for older adults

ABSTRACT This study examined age differences in effort devoted to completing cognitively demanding tasks. Fifty-two younger adults ages 18–30 years (M age = 21.19) and 57 older adults ages 61–93 years (M age = 76.56) completed a series of memory tests. Following each test, participants rated the test’s difficulty and had their blood pressure measured. Effort was indexed by systolic blood pressure response (SBP-R) with greater increases in SBP-R reflecting more effort. Multilevel modeling was used to examine age differences in the intraindividual association between trial-level subjective task difficulty and trial-level effort. Results showed that increases in task difficulty were significantly related to decreases in SBP-R for the older but not younger adults, suggesting the older adults disengaged from the tests they perceived as highly difficult. Findings support Selective Engagement Theory (Hess, 2014), which suggests the perceived cognitive costs of completing difficult tasks may reduce older adults’ motivation to engage in the tasks.

Compensatory brain activity pattern is not present in older adults during the n-back task performance-Findings based on EEG frequency analysis.

Cognitive ability is one of the most important enablers for successful aging. At the same time, cognitive decline is a well-documented phenomenon accompanying the aging process. Nevertheless, it is acknowledged that aging can also be related to positive processes that allow one to compensate for the decline. These processes include the compensatory brain activity of older adults primarily investigated using fMRI and PET. To strengthen the cognitive interpretation of compensatory brain activity in older adults, we searched for its indicators in brain activity measured by EEG. The study sample comprised 110 volunteers, including 50 older adults (60-75 years old) and 60 young adults (20-35 years old) who performed 1-back, 2-back, and 3-back tasks while recording the EEG signal. The study analyzed (1) the level of cognitive performance, including sensitivity index, the percentage of correct answers to the target, and the percentage of false alarm errors; (2) theta and alpha power for electrodes located in the frontal-midline (Fz, AF3, AF4, F3, F4, FC1, and FC2) and the centro-parietal (CP1, CP2, P3, P4, and Pz) areas. Cognitive performance was worse in older adults than in young adults, which manifested in a significantly lower sensitivity index and a significantly higher false alarm error rate at all levels of the n-back task difficulty. Simultaneously, performance worsened with increasing task difficulty regardless of age. Significantly lower theta power in the older participants was observed at all difficulty levels, even at the lowest one, where compensatory activity was expected. At the same time, at this difficulty level, cognitive performance was worse in older adults than in young adults, which could reduce the chances of observing compensatory brain activity. The significant decrease in theta power observed in both age groups with rising task difficulty can reflect a declining capacity for efficient cognitive functioning under increasing demands rather than adapting to this increase. Moreover, in young adults, alpha power decreased to some extent with increasing cognitive demand, reflecting adaptation to them, while in older adults, no analogous pattern was observed. In conclusion, based on the results of the current study, the presence of compensatory activity in older adults cannot be inferred.

Neurovascular Coupling in Acutely Concussed Adolescent Patients.

Neurovascular coupling (NVC) uniquely describes cerebrovascular response to neural activation and has demonstrated impairments following concussion in adult patients. It is currently unclear how adolescent patients experience impaired NVC acutely following concussion during this dynamic phase of physiological development. The purpose of this study was to investigate NVC in acutely concussed adolescent patients relative to controls. We recruited patients presenting to a sports medicine practice within 28 days of a concussion or a musculoskeletal injury (controls). Transcranial Doppler ultrasound was used to measure changes in patients' posterior cerebral artery (PCA) velocity in response to two progressively challenging visual tasks: (1) reading and (2) visual search. Each task was presented in five 1-min trials (20 sec eyes closed/40 sec eyes open). Resting PCA velocity data were derived by averaging PCA velocity across a 2-min baseline period that preceded the visual tasks. Filtered task data were converted to time-series curves representing 40 consecutive 1-sec averages for each trial. Curves were then averaged across the five trials and time-aligned to stimulus onset (eyes open) to generate a single ensemble-averaged 40-sec curve representing NVC response for each participant for each task. Independent t tests were used to assess group differences (concussion vs. control) in resting PCA velocity. Separate linear mixed-effects models were used to evaluate group differences (concussion vs. control) in NVC response profiles for both visual tasks and group-by-task interaction. Twenty-one concussion patients (female = 8 [38.1%]; age = 14.4 ± 1.9 years) and 20 controls (female = 7 [35.0%]; age = 14.4 ± 1.9 years) were included in our analysis. Average resting PCA velocity did not significantly differ between concussion patients (36.6 ± 8.0 cm/sec) and controls (39.3 ± 8.5 cm/sec) (t39 = 1.06; p = 0.30). There were no significant group differences in relative NVC response curves during the reading task (F1,1560 = 2.23; p = 0.14) or the visual search task (F1,1521 = 2.04; p = 0.15). In contrast, the differential response to task (e.g., increase from reading task to visual search task) was significantly greater in concussion patients than in controls (p < 0.0001). The NVC response to the visual search task was 7.1% higher than the response to reading in concussion patients relative to being 5.5% higher in controls. Our data indicate that concussed patients present with a significantly greater response to more difficult tasks than do controls, suggesting that concussed adolescents require increased neural resource allocation as task difficulty increases. The study provides insight into the neurophysiological consequences of concussion in adolescent patients.

Visuospatial cueing differences as a function of autistic traits.

Atypical orienting of visuospatial attention in autistic individuals or individuals with a high level of autistic-like traits (ALTs) has been well documented and viewed as a core feature underlying the development of autism. However, there has been limited testing of three alternative theoretical positions advanced to explain atypical orienting - difficulty in disengagement, cue indifference, and delay in orienting. Moreover, research commonly has not separated facilitation (reaction time difference between neutral and valid cues) and cost effects (reaction time difference between invalid and neutral cues) in orienting tasks. We addressed these limitations in two experiments that compared groups selected for Low- and High-ALT levels on exogenous and endogenous versions of the Posner cueing paradigm. Experiment 1 showed that High-ALT participants exhibited a significantly reduced cost effect compared to Low-ALT participants in the endogenous cueing task, although the overall orienting effect remained small. In Experiment 2, we increased task difficulty of the endogenous task to augment cueing effects. Results were comparable to Experiment 1 regarding the finding of a reduced cost effect for High-ALT participants on the endogenous cueing task and additionally demonstrated a reduced facilitation effect in High-ALT participants on the same task. No ALT group differences were observed on an exogenous cueing task included in Experiment 2. These findings suggest atypical orienting in High-ALT individuals may be attributable to general cue indifference, which implicates differences in top-down attentional processes between Low- and High-ALT individuals. We discuss how indifference to endogenous cues may contribute to social cognitive differences in autism.

Lower cognitive reserve is related to worse working memory performance in older adults after mTBI. An ERP study

ABSTRACT Objective Older adults (OA) after mild traumatic brain injury (mTBI) have a high risk of developing persistent post-injury cognitive impairments. Lower pre-morbid cognitive reserve (CR) is increasingly investigated as a risk factor for cognitive dysfunction in OA. However, how CR protects against effects of mTBI at the brain level remains largely understudied. Methods We examined 22 OA who sustained mTBI (mean 67.69 years, SD 5.11) in the sub-acute phase and 15 age- and CR-matched healthy OA (mean 68 years, SD 5.55) performing a three-level visual N-back task using electroencephalography. We calculated inverse efficiency scores of performance from accuracy and reaction times. Event-related potentials served as neurocognitive correlates of attentional (P2) and working memory (P3) processing. Results Overall, mTBI OA performed worse than healthy OA (p = 0.031). Lower CR generally decreased performance (p < 0.001). Furthermore, with increasing task difficulty, task performance was more affected by CR (p = 0.004). At the brain level, P2 amplitude was lower in mTBI OA than in healthy OA (p = 0.05). There was no clear effect of CR on P2 or P3 measures. Conclusion As mTBI OA with lower CR performed worse on a working-memory task, lower CR may be a risk factor for worse recovery after mTBI in this group.

Knowledge by omission: the significance of omissions in the 5-choice serial reaction time task.

The 5-choice serial reaction time task (5-CSRTT) is commonly used to assess attention in rodents. Manipulation of this task by decreasing the light stimulus duration is often used to probe attentional capacity and causes a decrease in accuracy and an increase in omissions. However, although a decrease in response accuracy is commonly interpreted as a decrease in attention, it is more difficult to interpret an increase in omissions in terms of attentional performance. Here we present a series of experiments in rats that seeks to investigate the origins of these key behavioral measures of attention in the 5-CSRTT. After an initial training in the 5-CSRTT, rats were tested in a variable stimulus duration procedure to increase task difficulty and probe visual attentional capacity under several specific controlled conditions. We found that response accuracy reflects visuospatial sustained attentional processing, as commonly interpreted, while response omission reflects rats' ignorance about the stimulus location, presumably due to failure to pay attention to the curved wall during its presentation. Moreover, when rats lack of relevant information, they choose not to respond instead of responding randomly. Finally, pretreatment with nicotine selectively decreased response omissions, without affecting response accuracy, particularly when the attentional demand was high. Overall, our results indicate that response accuracy and response omission thus correspond to two distinct attentional states.

Does vibrotactile stimulation of the auricular vagus nerve enhance working memory? A behavioral and physiological investigation

BackgroundWorking memory is essential to a wide range of cognitive functions and activities. Transcutaneous auricular vagus nerve stimulation (taVNS) is a promising method to improve working memory performance. However, the feasibility and scalability of electrical stimulation are constrained by several limitations, such as auricular discomfort and inconsistent electrical contact. ObjectiveWe aimed to develop a novel and practical method, vibrotactile taVNS, to improve working memory. Further, we investigated its effects on arousal, measured by skin conductance and pupil diameter. MethodThis study included 20 healthy participants. Behavioral response, skin conductance, and eye tracking data were concurrently recorded while the participants performed N-back tasks under three conditions: vibrotactile taVNS delivered to the cymba concha, earlobe (sham control), and no stimulation (baseline control). ResultsIn 4-back tasks, which demand maximal working memory capacity, active vibrotactile taVNS significantly improved the performance metric d′ compared to the baseline but not to the sham. Moreover, we found that the reduction rate of d′ with increasing task difficulty was significantly smaller during vibrotactile taVNS sessions than in both baseline and sham conditions. Arousal, measured as skin conductance and pupil diameter, declined over the course of the tasks. Vibrotactile taVNS rescued this arousal decline, leading to arousal levels corresponding to optimal working memory levels. Moreover, pupil diameter and skin conductance level were higher during high-cognitive-load tasks when vibrotactile taVNS was delivered to the concha compared to baseline and sham. ConclusionOur findings suggest that vibrotactile taVNS modulates the arousal pathway and could be a potential intervention for enhancing working memory.

Appetitively motivated tasks in the IntelliCage reveal a higher motivational cost of spatial learning in male than female mice.

The IntelliCage (IC) permits the assessment of the behavior and learning abilities of mice in a social home cage context. To overcome water deprivation as an aversive driver of learning, we developed protocols in which spatial learning is motivated appetitively by the preference of mice for sweetened over plain water. While plain water is available at all times, only correct task responses give access to sweetened water rewards. Under these conditions, C57BL/6J mice successfully mastered a corner preference task with the reversal and also learned a more difficult time-place task with reversal. However, the rate of responding to sweetened water decreased strongly with increasing task difficulty, indicating that learning challenges and reduced success in obtaining rewards decreased the motivation of the animals to seek sweetened water. While C57BL/6J mice of both sexes showed similar initial taste preferences and learned similarly well in simple learning tasks, the rate of responding to sweetened water and performance dropped more rapidly in male than in female mice in response to increasing learning challenges. Taken together, our data indicate that male mice can have a disadvantage relative to females in mastering difficult, appetitively motivated learning tasks, likely due to sex differences in value-based decision-making.

Assessment of Drivers' Mental Workload by Multimodal Measures during Auditory-Based Dual-Task Driving Scenarios.

Assessing drivers' mental workload is crucial for reducing road accidents. This study examined drivers' mental workload in a simulated auditory-based dual-task driving scenario, with driving tasks as the main task, and auditory-based N-back tasks as the secondary task. A total of three levels of mental workload (i.e., low, medium, high) were manipulated by varying the difficulty levels of the secondary task (i.e., no presence of secondary task, 1-back, 2-back). Multimodal measures, including a set of subjective measures, physiological measures, and behavioral performance measures, were collected during the experiment. The results showed that an increase in task difficulty led to increased subjective ratings of mental workload and a decrease in task performance for the secondary N-back tasks. Significant differences were observed across the different levels of mental workload in multimodal physiological measures, such as delta waves in EEG signals, fixation distance in eye movement signals, time- and frequency-domain measures in ECG signals, and skin conductance in EDA signals. In addition, four driving performance measures related to vehicle velocity and the deviation of pedal input and vehicle position also showed sensitivity to the changes in drivers' mental workload. The findings from this study can contribute to a comprehensive understanding of effective measures for mental workload assessment in driving scenarios and to the development of smart driving systems for the accurate recognition of drivers' mental states.

Heart rate response to cognitive load as a marker of depression and increased anxiety.

Understanding the interplay between cardiovascular parameters, cognitive stress induced by increasing load, and mental well-being is vital for the development of integrated health strategies today. By monitoring physiological signals like electrocardiogram (ECG) and photoplethysmogram (PPG) in real time, researchers can discover how cognitive tasks influence both cardiovascular and mental health. Cardiac biomarkers resulting from cognitive strain act as indicators of autonomic nervous system function, potentially reflecting conditions related to heart and mental health, including depression and anxiety. The purpose of this study is to investigate how cognitive load affects ECG and PPG measurements and whether these can signal early cardiovascular changes during depression and anxiety disorders. Ninety participants aged 18 to 45 years, ranging from symptom-free individuals to those with diverse psychological conditions, were assessed using psychological questionnaires and anamnesis. ECG and PPG monitoring were conducted as volunteers engaged in a cognitive 1-back task consisting of two separate blocks, each with six progressively challenging levels. The participants' responses were analyzed to correlate physiological and psychological data with cognitive stressors and outcomes. The study confirmed a notable interdependence between anxiety and depression, and cardiovascular responses. Task accuracy decreased with increased task difficulty. A strong relationship between PPG-measured heart rate and markers of depression and trait anxiety was observed. Increasing task difficulty corresponded to an increase in heart rate, linked with elevated levels of depression and trait anxiety. A strong relationship between ECG-measured heart rate and anxiety attacks was observed. Increasing task difficulty corresponded to an increase in heart rate, linked with elevated levels of anxiety attacks, although this association decreased under more challenging conditions. The findings underscore the predictive importance of ECG and PPG heart rate parameters in mental health assessment, particularly depression and anxiety under cognitive stress induced by increasing load. We discuss mechanisms of sympathetic activation explaining these differences. Our research outcomes have implications for clinical assessments and wearable device algorithms for more precise, personalized mental health diagnostics.

A Group Level Analysis of Self-evaluations Associated with Cognitive Load

Self-evaluation, or self-rating, is the process by which people evaluate themselves with the purpose of improving several aspects of their personalities or skills and it is closely related to the cognitive function of metacognition. The purpose of the study was to investigate the degree of implication of various brain areas to meta-cognition as it relates to subjective ratings of cognitive effort when performing mathematical problems of different complexity. To achieve this, participants were recruited to solve mathematical problems (addition, subtraction, multiplication, and division) in three levels of difficulty, while inside an fMRI scanner. After solving a given task, they were asked to evaluate the amount of effort they spent to solve it. Brain signal was collected during their answers, which was then analyzed with the aid of computer software. Results of the analysis show that increases in task difficulty activate the frontal lobe, cingulate and insular cortex areas. The parietal lobule, the precuneus and the cingulate gyrus were found to be active as well as during all four mathematical operations.

Bilingual problem size effect: an ERP study of multiplication verification and production in two languages.

The problem size effect (PSE) is defined by better performance solving small problems (e.g., 2x4) than large problems (e.g., 8x9). For monolinguals, the PSE is larger when problems are presented in unfamiliar formats (e.g., written words), reflecting increased processing difficulty. Bilinguals are typically faster and more accurate at retrieving multiplication facts in the language of learning (LA+) than in their other language (LA-). We hypothesized that the less familiar arithmetic language (i.e., LA-) would elicit larger PSEs than LA+. Here, fluent Spanish-English bilingual adults verified spoken multiplication problems presented in LA+ and LA- while event-related potentials (ERPs) were recorded (Experiment 1A). To further promote language differences, we increased task difficulty by presenting problems at a faster pace (Experiment 1B) and requiring bilinguals to verbally produce solutions (Experiment 2). Language differences in performance were only observed for Experiment 2, where solutions were produced more slowly in LA- than LA+. In the ERPs, a PSE was driven by larger P300s for small than large solutions. A language effect was only observed under time pressure where LA- elicited a PSE at the 2nd operand. Additionally, the PSE was smaller for LA- at the solution. This suggests that categorizing multiplication facts is more effortful in LA-. In sum, very subtle language differences arise in fluent bilinguals when problems are more difficult, such as larger problems presented under time pressure in a weaker language. Critically, the effect of LA+ is at the level of response production and not access to the facts from memory.