Chronic insomnia (CI) is a prevalent disorder associated with prefrontal cortex (PFC) dysfunction, and it can significantly impair quality of life and psychological well-being. This study explores the use of functional near-infrared spectroscopy (fNIRS) as a tool for rapid screening of CI and for evaluating the efficacy of repetitive transcranial magnetic stimulation (rTMS) in improving brain function and clinical symptoms in CI patients.

A total of 60 participants were enrolled, including 30 healthy controls (HCs) and 30 CI patients. CI patients received a two-week intervention of 1 Hz rTMS targeting the right dorsolateral prefrontal cortex (DLPFC). Symptom severity was assessed using the Pittsburgh Sleep Quality Index (PSQI), Self-Rating Anxiety Scale (SAS), and Self-Rating Depression Scale (SDS). Hemodynamic differences between CI patients and HCs during a verbal fluency task (VFT) were analyzed using fNIRS.

HCs exhibited significantly lower PSQI, SAS, and SDS scores compared to CI patients (p < 0.05). During the VFT, oxygenated hemoglobin (oxy-Hb) levels in the DLPFC and medial prefrontal cortex (mPFC) were significantly higher in HCs than in CI patients (p < 0.05). Following rTMS treatment, CI patients demonstrated significantly increased activation in relevant brain regions compared to pre-treatment levels.

fNIRS has shown considerable potential as a valuable tool for the screening and diagnosis of CI. Compared to HCs, CI patients exhibited significantly weaker PFC responses during the VFT. rTMS treatment was found to alleviate symptoms in CI patients, likely due to its ability to enhance PFC activation.

Major depressive disorder (MDD) and generalized anxiety disorder (GAD) are highly prevalent mental disorders in psychiatry, but their overlapping symptoms often complicate precise diagnoses. This study aims to explore differential brain activation patterns in healthy controls (HC), MDD, and GAD groups through functional near-infrared spectroscopy (fNIRS) during the verbal fluency task (VFT) to enhance the accuracy of clinical diagnoses.

This study recruited 30 patients with MDD, 45 patients with GAD, and 34 demographically matched HCs. Hemodynamic changes in the prefrontal cortex (PFC) and temporal lobes were measured using a 48-channel fNIRS during the VFT task. Demographics information, clinical characteristics and VFT performance were also recorded.

Compared to HCs, both MDD and GAD share a neurobiological phenotype of hypoactivation in the dorsolateral prefrontal cortex (DLPFC) and medial prefrontal cortex (mPFC) during VFT. Moreover, MDD patients exhibited significantly greater hypoactivation in the left DLPFC and mPFC than GAD patients.

Although both GAD and MDD patients exhibit disrupted cortical function, the impairment is less severe in GAD. These findings provide preliminary neurophysiological evidence supporting the utility of the fNIRS-VFT paradigm in differentiating GAD from MDD. This approach may complement traditional diagnostic methods, inform targeted interventions, and ultimately enhance patient outcomes.

Depression is a common mental disorder that significantly impacts global well-being. Although stress is a major contributor to depression, not all stress leads to depressive outcomes due to differences in stress perception. Understanding the neural mechanisms of stress perception may help identify biomarkers for targeted interventions to alleviate stress-related depression.

This study included 113 participants. Each participant completed a Verbal Fluency Task (VFT) while undergoing functional near-infrared spectroscopy (fNIRS) to monitor brain activity. Oxyhemoglobin (Oxy-Hb) concentration data were analyzed using Matlab, and PROCESS v4.1 to examine neural mechanisms connecting stress perception and depression.

Correlation analysis showed a significant negative association between depression severity and Oxy-Hb concentration in several brain regions, including the bilateral dorsolateral prefrontal cortex (DLPFC), bilateral Broca's area (BA), right frontal pole (FP), and right orbitofrontal cortex (OFC). Mediation and moderation analyses revealed that the bilateral DLPFC serves as a key mediator in the relationship between stress perception and depression, with the supplementary motor area (SMA) acts as a moderator. Functional differentiation was observed, with the left DLPFC and left SMA influencing the effect of nervous on depression, and the right DLPFC and right SMA influencing the effect of uncontrolled on depression.

The bilateral DLPFC and SMA play critical roles in mediating and moderating stress perception's impact on depression, suggesting these regions as potential targets for interventions in stress-related depressive disorders.

To systematically review technologies that objectively measure cognitive workload (CWL) in surgery, assessing their psychometric and methodological characteristics.

Surgical tasks involving concurrent clinical decision-making and the safe application of technical and non-technical skills require a substantial cognitive demand and resource utilization. Cognitive overload leads to impaired clinical decision-making and performance decline. Assessing CWL could enable interventions to alleviate burden and improve patient safety.

Ovid MEDLINE, OVID Embase, the Cochrane Library, and IEEE Xplore databases were searched from inception to August 2023. Full-text, peer-reviewed original studies in a population of surgeons, anesthesiologists or interventional radiologists were considered, with no publication date constraints. Study population, task paradigm, stressor, cognitive load theory (CLT) domain, objective and subjective parameters, statistical analysis, and results were extracted. Studies were assessed for (1) definition of CWL; (2) details of the clinical task paradigm; and (3) objective CWL assessment tool. Assessment tools were evaluated using psychometric and methodological characteristics.

A total of 10,790 studies were identified; 9004 were screened; 269 full studies were assessed for eligibility, of which 67 met inclusion criteria. The most widely used assessment modalities were autonomic (32 eye studies and 24 cardiac). Intrinsic workload (eg, task complexity) and germane workload (effect of training or expertize) were the most prevalent designs investigated. CWL was not defined in 30 of 67 studies (44.8%). Sensitivity was greatest for neurophysiological instruments (100% EEG, 80% fNIRS); and across modalities accuracy increased with multisensor recordings. Specificity was limited to cardiac and ocular metrics, and was found to be suboptimal (50% and 66.67%). Cardiac sensors were the least intrusive, with 54.2% of studies conducted in naturalistic clinical environments (higher ecological validity).

Physiological metrics provide an accessible, objective assessment of CWL, but dependence on autonomic function negates selectivity and diagnosticity. Neurophysiological measures demonstrate favorable sensitivity, directly measuring brain activation as a correlate of cognitive state. Lacking an objective gold standard at present, we recommend the concurrent use of multimodal objective sensors and subjective tools for cross-validation. A theoretical and technical framework for objective assessment of CWL is required to overcome the heterogeneity of methodological reporting, data processing, and analysis.

Stress is both a driver of objective performance impairments and a source of negative user experience of technology. This review addresses future directions for research on stress and ergonomics in the digital age. The review is structured around three levels of analysis. At the individual user level, stress is elicited by novel technologies and tasks including interaction with AI and robots, working in Virtual Reality, and operating autonomous vehicles. At the organisational level, novel, potentially stressful challenges include maintaining cybersecurity, surveillance and monitoring of employees supported by technology, and addressing bias and discrimination in the workplace. At the sociocultural level, technology, values and norms are evolving symbiotically, raising novel demands illustrated with respect to interactions with social media and new ethical challenges. We also briefly review the promise of neuroergonomics and emotional design to support stress mitigation. We conclude with seven high-level principles that may guide future work.

Functional near-infrared spectroscopy (fNIRS) offers a portable, cost-effective alternative to functional magnetic resonance imaging (fMRI) for noninvasively measuring neural activity. However, fNIRS measurements are limited to cortical regions near the scalp, missing important medial and deeper brain areas. We introduce a predictive model that maps prefrontal fNIRS signals to whole-brain fMRI activity during movie-watching. By aligning neural responses to a common audiovisual stimulus, our approach leverages shared dynamics across imaging modalities to map fNIRS signals to broader neural activity patterns. We scanned participants with fNIRS and utilized a publicly available fMRI dataset of participants watching the same TV episode. The model was trained on the first half of the episode and tested on a held-out participant watching the second half to assess cross-individual and cross-stimulus generalizability. The model significantly predicted fMRI time courses in 66 out of 122 brain regions, including areas otherwise inaccessible to fNIRS. It also replicated intersubject functional connectivity patterns and retained semantic information about the movie content. The model generalized to an independent dataset from a different TV series, suggesting it captures robust cross-modal mappings across stimuli. Our publicly available models enable researchers to infer broader neural dynamics from localized fNIRS data during naturalistic tasks.

BackgroundBalance impairments and fatigue are common after stroke and impact physical therapy assessments and treatments. Reasons are multifactorial and include motor dysfunction and changes to cortical activation poststroke. The prefrontal cortex (PFC) is involved in motor control; yet, limited research has explored cortical activation during common physical therapy balance tasks or the link with fatigue.ObjectivesDuring standing balance tasks, the objective was to determine whether PFC activation levels: (1) change between tasks, (2) are asymmetric, and (3) are associated with fatigue.MethodsPatients with hemiparesis were recruited from an inpatient stroke unit and functional near-infrared spectroscopy was applied bilaterally over the PFC to measure cortical activation during balance tasks. Fatigue was assessed using the Fatigue Severity Scale (FSS).ResultsNine participants were included. PFC activation during semi-tandem stance showed greater amplitude than during double-leg stance, indicating more cortical activation. Bilateral PFC activation was observed during both tasks. Participants with greater fatigue (higher FSS score) showed more activation in the ipsilesional PFC than the contralesional PFC.ConclusionPFC activation may occur when performing more challenging balance postures, potentially indicating compensatory activation, and may be linked with greater fatigue.

Chronic post-surgical pain (CPSP) poses significant socioeconomic and humanitarian challenges. This study investigated relationships between resting-state neural activation in the somatosensory cortex (SMC) and emotional functioning outcomes (depression, anxiety, perceived stress), and between prefrontal cortex (PFC) activation and chronic stress, measured by hair cortisol concentration (HCC); and whether pain intensity moderates these relationships in females with CPSP. Twenty-nine females with CPSP reported baseline pain, completed emotional functioning questionnaires, underwent functional Near-Infrared Spectroscopy, and provided hair samples for HCC analysis. Pearson's correlation examined associations between emotional functioning and SMC activation, and between HCC and PFC activation. Benjamini-Hochberg correction adjusted for multiple comparisons. Significant correlations were further tested using moderation analyses to assess whether pain intensity influenced these associations. Left SMC activation was positively correlated with depressive symptoms (r = 0.505, pFDR = 0.036) and anxiety(r = 0.705, pFDR = 0.039). Right lateral PFC activation showed a negative correlation with HCC (r = -0.475, pFDR = 0.048). Pain intensity did not significantly moderate these relationships. Findings suggest associations between brain activity and emotional functioning in females with CPSP, highlighting potential neural targets for future interventions. This study supports the utility of multimodal approaches to further phenotype CPSP and inform precision medicine strategies.

Early infant phonological and non-phonological perceptual abilities are crucial for future language learning. Previous studies have focused on the changes in the cerebral cortex of infants and toddlers during speech perception, while the changes in the cerebral cortex during non-speech perception remain poorly understood.

This study aimed to investigate cortical activation patterns and differences in full-term healthy newborns under different speech and non-speech stimuli by functional near-infrared spectroscopy (fNIRS).

The cohort included 36 full-term healthy neonates (7.4 ± 6.0 days) exposed to two types of speech stimuli (native Mandarin and non-native Spanish) and three non-speech stimuli (music, cat calls, and noise) in a block design. Brain activity was monitored across eight brain regions of interest (ROIs) were monitored using fNIRS (54 channels): frontal pole area (FPA), middle frontal gyrus (MFG), primary sensorimotor cortex, middle temporal gyrus (MTG), superior temporal gyrus (STG), fusiform gyrus (FFG), Wernicke's area, and Broca's area.

Mandarin stimulation activated all ROIs in newborns. Changes in oxygenated hemoglobin concentrations in FPA, MFG, STG, MTG, FFG, Wernicke's area, and Broca's area were significantly higher during Mandarin exposure compared to Spanish (p < 0.05). MTG activation was significantly greater during Mandarin exposure compared to cat calls (p = 0.005), music (p = 0.040), and noise (p < 0.001). Similarly, MFG and Broca's area showed significantly greater activation during music exposure compared to Spanish and noise stimuli (p < 0.05).

The newborn brain can perceive various speech and non-speech stimuli, demonstrating a preference for native language stimuli, followed by music. The ability to perceive non-native languages, animal calls, and noise appears more limited. These findings could provide some references for future research on infant and toddler language development.

Attention plays a vital part in the cognitive process, where different kinds of attention are associated with separate brain mechanisms. The objective of this research was to investigate the patterns of brain activation and functional connectivity in middle-aged and elderly individuals, while they were engaged in various attentional tasks, with the intention of establishing a reference foundation for the clinical treatment of attention disorders.

A total of 44 healthy middle-aged and elderly persons (47.1% women) aged over 40 were enrolled in this study. The digital cancellation test (DCT), the paced auditory serial addition test (PASAT), the Stroop colour-word test, and the trail making test (TMT) are, respectively, associated with four types of attention tasks: sustained attention, divided attention, selective attention, and attention shifting. Functional near-infrared spectroscopic imaging was employed to measure the concentration of brain oxyhaemoglobin in the subjects, while they were performing these four attention tasks.

In this study, we found distinct activation patterns in brain areas, such as BA-3, BA-4, BA-6, and others. Functional connectivity analysis revealed that the frontal and right parietal lobes consistently showed higher density and strength of connections across tasks, with the PASAT task exhibiting the highest number of connections exceeding the threshold. Notably, the DCT task demonstrated significant correlations in oxygen fluctuations among several brain regions, while the TMT-B task highlighted strong functional connectivity within the bilateral frontal and parietal lobes.

This research provides evidence that middle-aged and elderly people have different brain activation and functional connectivity patterns in different attentional tasks, suggesting individualized treatment for attention disorder patients based on impairment type and location.

This study has been registered through the Chinese Clinical Trial Registry (ChiCTR2400087755).

Classroom teaching is essential for cognitive development and cultural evolution, yet its neurocognitive mechanisms remain unclear. Here, this is explored in a university graduate course by combining wearable functional near-infrared spectroscopy (fNIRS) and machine learning models. The results show that blended teaching involving both students' recalling and teachers' lecturing leads to better learning outcomes than lecturing alone. Moreover, during the same lecturing phase, blended teaching induces knowledge construction in the middle frontal cortex (MFC), while lecturing alone induces knowledge representation in the right temporoparietal junction (TPJ), with the former significantly correlating with the final learning outcomes. Additionally, the MFC's construction begins during earlier recalling but is significantly facilitated by later lecturing. Finally, when teacher's TPJ activity precedes that of students' MFC, significant teacher-student neural synchronization is observed during lecturing of blended teaching and is correlated with learning outcomes. These findings suggest that, in the real classroom teaching, the MFC serves as a hub of a rapid cortical learning process, supporting knowledge construction through a projection from the teacher's TPJ.

Empirical studies have shown immediate detrimental effects of TV viewing on children's executive functions (EFs). Existing theories of TV viewing have proposed that such depletion could occur due to fantastical cartoons triggering an attention bias towards salient features of the stimuli (e.g., stimulus-driven exogenous attention). However, a co-occurrence of salient visual features known to drive attention exogenously in fantastical cartoons means it is unclear which aspect of the content is problematic. In the present study, we matched clips on visual saliency to isolate and test the short-term impact of fantastical content. Specifically, we tested (1) performance on an inhibitory control (IC) task (a gaze-contingent anti-saccade task) as a measure of EF depletion, whilst 36 toddlers (18 months) viewed cartoons with and without fantastical events (7-min viewing duration), and (2) whether differences in IC are associated with increased stimulus-driven exogenous attention. Results confirmed an immediate detrimental effect of fantastical cartoons on toddlers' endogenous control (indexed by anti-saccade behaviours), with toddlers less able to inhibit looks to a distractor to make anticipatory looks to a target. However, fixation durations (FDs) during cartoon viewing and speed of orienting to a distractor on the anti-saccade task did not differ between the two viewing conditions, suggesting no effects on exogenously driven attention. These results point to a detrimental impact of fantastical cartoons on endogenous control mechanisms, which may have arisen from cognitive processing difficulties.

Short-term memory poses a significant challenge, involving complex processes of image perception, memory formation, and execution. However, the mechanisms underlying the formation, storage, and execution of short-term memory remain poorly understood.

In this study, 41 healthy college students participated in a memory challenge test designed to investigate these processes. Functional near-infrared spectroscopy (fNIRS) was employed to measure dynamic changes in hemoglobin concentrations in specific cortical regions, while facial expressions and vital signs were recorded in real-time during the tests.

The results revealed heightened activity in the inferior prefrontal gyrus, visual association cortex, pre-motor cortex, and supplementary motor cortex. Functional connectivity between these regions was significantly enhanced during the tasks, and inter-group differences decreased over time. Participants with superior short-term memory exhibited lower levels of negative emotional expressions and higher heart rates compared to those with weaker memory performance. These findings suggest that cortical interconnectivity and adequate cerebral blood oxygenation play critical roles in enhancing short-term memory capacity. This has important implications for education, as it highlights strategies for cultivating attention, training memory skills, and improving memory integration abilities.

This study aimed to investigate age-related changes in brain functional connectivity during various motor and cognitive tasks, providing evidence for evaluating and intervening in brain aging.

15 elderly participants (ELD) and 30 young controls (YOU) were assessed. fNIRS haemodynamic responses were recorded during the Purdue nail board motor task, continuous minus 7 cognitive task, and motor-cognitive dual task. Differences in brain activation, functional connectivity, integral values, and barycentre values between the groups were compared using oxygenated haemoglobin (HbO) concentrations over time.

The ELD group performed significantly worse than the YOU group (p < 0.05). ELD participants showed significantly lower activation in the LSMA during motor tasks (p < 0.05), the RDLPFC and LDLPFC during cognitive tasks (p < 0.05), and both RSMA and LSMA during dual tasks (p < 0.05). Functional connectivity between LDLPFC, RSMA, LSMA, and RDLPFC-LDLPFC, LSMA-RSMA in the ELD group was significantly lower than in the YOU group (p < 0.05). The ELD group also had lower connectivity in RSMA, RDLPFC-LDLPFC, and LSMA-RSMA during cognitive tasks (p < 0.05). The centre of gravity for the ELD group was significantly lower during dual tasks compared to the YOU group (p < 0.05). In cognitive tasks, the ELD group showed significantly lower RSMA centre of gravity and integral values compared to dual tasks (p = 0.05).

Elderly individuals exhibit lower cortical brain connectivity than young people across various tasks. fNIRS-based cerebral haemodynamics provide a useful quantitative measure for evaluating age-related brain changes.

Occupational workload can contribute to significant health problems such as chronic stress, fatigue and burnout. To investigate the underlying mechanisms, it is necessary to monitor brain activity in real work environments. Functional near-infrared spectroscopy (fNIRS) is a portable, non-invasive neuroimaging method that captures neural correlates of occupational workload under natural conditions. However, despite its increasing application, a comprehensive overview of fNIRS-based research in this field is lacking. Therefore, this systematic review examines how fNIRS can be utilized to investigate occupational workload.

Following PRISMA 2020 guidelines, we conducted our systematic review by searching Web of Science, PubMed, and Scopus between November 15, 2023 and March 20, 2025. We included all studies published in English or German at any date, as long as they examined healthy adult professionals performing occupational tasks with functional near-infrared spectroscopy (fNIRS). Extracted data included study characteristics, workload details, signal processing methods, main fNIRS findings, and study quality, assessed using the JBI Critical Appraisal Tool.

We included 41 studies. Of these, 23 reported a significant increase in oxygenated hemoglobin (HbO) concentration and functional connectivity in the prefrontal cortex (PFC) under higher occupational workload conditions. Only five studies examined typical office tasks. Nine studies analyzed differences in cortical activation between experts and novices, with experts showing increased HbO concentration in the PFC than novices. Regarding methodology, 26 studies used standardized optode placements, while only 17 applied systemic and extracerebral artifact correction. Small sample sizes and the absence of randomized controlled trials limited the reliability and reproducibility of the findings.

Functional near-infrared spectroscopy effectively detects neural correlates of occupational workload and provides objective insights into cognitive demands in real-world work settings. Standardizing optode placement, harmonizing signal-processing methods, and increasing sample sizes would enhance the validity and comparability of future research. Expanding investigations to typical office environments is also crucial for understanding daily workload and for developing interventions that promote employee well-being and productivity. Overall, fNIRS represents a promising tool for establishing evidence-based workplace health promotion strategies across diverse occupational settings.

Subjective evaluation of a sport event in real time is normally assessed using self-report measures, but neural indices of evaluative processing may provide new insights. The extent of evaluative processing of a sporting event at the neural level may depend on the degree of emotional investment by the viewer, as well as the key moment of the game play being observed. Those with high ego involvement might show more activation within evaluative processing nodes, and this pattern may be most pronounced during critical moments of game play. In the current study, we examined neural activations within the medial and lateral prefrontal cortex during game play as a function of ego involvement, using video clips featuring key moments in a European league ice hockey game. A total of 343 participants were pre-screened to identify high (n = 11) and low (n = 9) ego-involved individuals. These subgroups then viewed a game segment containing 12 key play moments, while undergoing neuroimaging using functional near-infrared spectroscopy (fNIRS). Findings indicated more engagement of the dorsomedial prefrontal cortex (dmPFC) throughout all key moments for high ego-involved participants, but particularly during critical game moments. Overall, findings suggest that neural indices of evaluative processing might contribute meaningfully to understanding when emotionally invested individuals are most engaged in an action sequence during a sporting event.

Functional near-infrared spectroscopy (fNIRS) has become a well-established tool for neuroscience research and been suggested as a potential biomarker during clinical assessment in individuals with mental disorders. Biomarker need to be objective indications of biological processes which can be measured accurately and reproducibly. Despite various applications in clinical research, test-retest reliability of the fNIRS signal has not yet been evaluated sufficiently. To assess reliability of the fNIRS signal during tasks of executive functions, a group of 34 healthy subjects (13 male, 21 female) were tested twice for inhibitory control and working memory. On a group level results show a specific activation pattern throughout the two sessions, reflecting a task-related frontal network associated with the assessed cognitive functions. On the individual level the retest reliability of the activation patterns were considerably lower and differed strongly between participants. In conclusion, the interpretation of fNIRS signal on a single subject level is partially hampered by its low reliability. More studies are needed to optimize the retest reliability of fNIRS and to be applied on a routine basis in developmental research.

Individuals' risk preferences have been shown to influence their decision-making in various contexts. However, the neural mechanisms underlying the relationship between risk preference and decision-making in a social setting remain unclear. This study utilized functional near-infrared spectroscopy (fNIRS) to investigate the neural correlates of dyadic decision-making under risk and the modulating effect of individual risk preference.

This study examined the impact of risk preference on group decision-making using a two-phase experimental design. Based on G-power software calculations, 168 right-handed participants (62 males, 106 females, mean age 21.26±1.70) were recruited. Participants first completed a single-player Sequential Risk Task to measure risk preference, followed by group classification into three groups: Risky&Risky, Risky&Safe, and Safe&Safe. Task performance and decision-making behavior were recorded. Functional Near-Infrared Spectroscopy (fNIRS) was employed to measure cortical activation in the prefrontal cortex, focusing on inter-brain synchrony and coupling directionality using wavelet coherence and Granger causality(GC) analyses. Data were preprocessed to remove noise, and statistical analyses included repeated measures ANOVAs, Support Vector Regression and multiple regression analyses.

The study investigated dyadic risky decision-making among different paired groups, and the "Risky&Risky" group showed the highest risk-seeking behavior, with a significant main effect (F(2,81) = 7.438, P = 0.001). Inter-brain synchrony showed significance during outcome periods characterized by positive feedback, notably being higher within the "Risky&Risky" group. Granger causality analysis unveiled unique brain connectivity patterns, indicating that the GC values of "Risky&Safe" pairs increased during the diversion condition and decreased during the cooperation condition in comparison to other pairs, albeit without reaching statistical significance. Regression analysis indicated that OFC-mdlPFC GC values and personality traits were significant predictors of risk-taking, with the moderation of these effects by group membership (R²adjusted = 0.173 and 0.191).

This study employed fNIRS hyperscanning to investigate how individual differences in risk preference impact decision-making in dyadic contexts. The results indicated that variations in connectivity and information transfer between the orbitofrontal and medial prefrontal cortices underlie the distinct risk-taking behaviors exhibited by dyadic pairs. These findings underscore the pivotal role of affective and cognitive control mechanisms and individual risk personality traits in cooperative decision-making under conditions of uncertainty.

Reinvestment is a psychological phenomenon during which people consciously engage in controlling their movements (i.e., movement-specific reinvestment) or decision making (i.e., decision-specific reinvestment). This can result in performance deterioration and can have detrimental consequences for individuals in various sports.

This systematic review aimed to identify psychophysiological correlates of reinvestment to tackle the need for more objective measurements of reinvestment and to develop interventions to counteract performance-related decrements in the future. Considering brain, parasympathetic and oculomotor activity, jointly adds a holistic perspective on mechanisms underlying reinvestment.

We conducted a systematic literature search using the PRISMA guidelines in three electronic databases (Pubmed, Web of Science and SportDiscus) on 20th of November 2024. The included studies assessed reinvestment together with psychophysiological parameters. The risk of bias of the included studies was assessed by the authors using "The Joanna Briggs Institute Critical Appraisal Checklist for Analytical Cross Sectional Studies" (Moola et al., 2020).

A total of N = 21 studies containing a total of 791 participants were included. Of these, twelve studies considered brain activity, five considered parasympathetic cardiac activity, and two considered heart rate. Finally, two studies considered gaze behavior.

The findings indicate potential relationships between reinvestment and the considered psychophysiological parameters, but methods and findings appear heterogeneous in terms of task variability, population groups, and study design. To be able to draw more accurate conclusions, more systematic research programs are required to move towards a better holistic understanding of the psychophysiological correlates of reinvestment.

Flow is the state of optimal experience which can lead to outstanding performance. Our study demonstrates the feasibility of detecting and monitoring flow using wearable devices. Twenty-eight Hungarian adults participated in the experiment. They played a game at different levels to induce flow and anti-flow states, which was tested with questionnaires. We measured electroencephalography (EEG), heart rate (HR), blood oxygen saturation (SpO2) and galvanic skin response (GSR) signals as well as head and hand motion. We isolated EEG delta, theta, alpha and beta band power, HR, SpO2 and GSR average and standard deviation, as well as acceleration and angular velocity standard deviation. In flow condition, alpha and theta power were the dominant components, in accordance with the transient hypofrontality hypothesis. We also replicated the U-shaped characteristic of the heart rate variability; in addition, we propose an inverse U-shaped and a U-shaped characteristic for SpO2 and SpO2 variability, respectively. On the basis of motion tracking, subjects were the least physically active in flow, signifying a focused state, and the most active in boredom. Our results support the applicability of lightweight, wearable devices for monitoring mental state that can be utilized to improve well-being at work or in everyday situations.

A shared understanding of terminology is essential for clear scientific communication and minimizing misconceptions. This is particularly challenging in rapidly expanding, interdisciplinary domains that utilize functional near-infrared spectroscopy (fNIRS), where researchers come from diverse backgrounds and apply their expertise in fields such as engineering, neuroscience, and psychology.

The fNIRS Glossary Project was established to develop a community-sourced glossary covering key fNIRS terms, including those related to the continuous-wave (CW), frequency-domain (FD), and time-domain (TD) NIRS techniques.

The glossary was collaboratively developed by a diverse group of 76 fNIRS researchers, representing a wide range of career stages (from PhD students to experts) and disciplines. This collaborative process, structured across five phases, ensured the glossary's depth and comprehensiveness.

The glossary features over 300 terms categorized into six key domains: analysis, experimental design, hardware, neuroscience, mathematics, and physics. It also includes abbreviations, symbols, synonyms, references, alternative definitions, and figures where relevant.

The fNIRS glossary provides a community-sourced resource that facilitates education and effective scientific communication within the fNIRS community and related fields. By lowering barriers to learning and engaging with fNIRS, the glossary is poised to benefit a broad spectrum of researchers, including those with limited access to educational resources.

The influence of hypoxia - a condition where tissues are under oxygen deficiency - on the human brain under functional load has not been fully understood yet. This study aims to analyse the effects of hypoxia on the brain's haemodynamic response under visual stimulation, using the in-house developed functional near-infrared spectroscopy system and to quantify the hemodynamic response. Our results (median, 25th and 75th percentile) demonstrate the amplitude of the oxygenated haemoglobin functional response during hypoxia 0.30 µM (0.27, 0.41) was lower compared with the normoxia 0.63 µM (0.54, 0.93) and hyperoxia 0.73 µM (0.43, 1.09). No statistical significance is observed for the deoxygenated haemoglobin changes. The hypoxia has a statistically significant effect on the amplitude of the haemodynamic response (p < 0.001).

A fundamental characteristic of social exchanges is the synchronization of individuals' behaviors, physiological responses, and neural activity. However, the association between how individuals communicate in terms of emotional content and expressed associative knowledge and interpersonal synchrony has been scarcely investigated so far. This study addresses this research gap by bridging recent advances in cognitive neuroscience data, affective computing, and cognitive data science frameworks. Using functional near-infrared spectroscopy (fNIRS) hyperscanning, prefrontal neural data were collected during social interactions involving 84 participants (i.e., 42 dyads) aged 18-35 years. Wavelet transform coherence was used to assess interpersonal neural synchrony between participants. We used manual transcription of dialogues and automated methods to codify transcriptions as emotional levels and syntactic/semantic networks. Our quantitative findings reveal higher than random expectations levels of interpersonal neural synchrony in the superior frontal gyrus (q = .038) and the bilateral middle frontal gyri (q< .001, q< .001). Linear mixed models based on dialogues' emotional content only significantly predicted interpersonal neural synchrony across the prefrontal cortex (Rmarginal2=3.62%). Conversely, models relying on syntactic/semantic features were more effective at the local level, for predicting brain synchrony in the right middle frontal gyrus (Rmarginal2=9.97%). Generally, models based on the emotional content of dialogues were not effective when limited to data from one region of interest at a time, whereas models based on syntactic/semantic features show the opposite trend, losing predictive power when incorporating data from all regions of interest. Moreover, we found an interplay between emotions and associative knowledge in predicting brain synchrony, providing quantitative support to the major role played by these linguistic components in social interactions and in prefrontal processes. Our study identifies a mind-brain duality in emotions and associative knowledge reflecting neural synchrony levels, opening new ways for investigating human interactions.

Repetitive transcranial magnetic stimulation (rTMS) emerges as a promising non-invasive neuromodulation technique for the treatment of patients with disorders of consciousness (DOC). The selection of rTMS parameters significantly influences the clinical therapeutic effects. However, the differences in spatiotemporal responsiveness of the brain under different rTMS stimulation frequencies remain unclear. In this pilot study, functional near-infrared spectroscopy (fNIRS) was used to evaluate the spatiotemporal differences in hemodynamic responses elicited by rTMS at different frequencies (1, 5, 10, 15, and 20 Hz) over left dorsolateral prefrontal cortex (F3). The results showed that the distribution patterns of the rTMS-evoked hemodynamic responses varied across different frequencies, indicating that rTMS frequency influences the hemodynamic responses in patients with DOC. Specifically, 10 Hz rTMS evoked strong positive hemodynamic responses over the frontal cortex, particularly in the right dorsolateral prefrontal cortex (R-DLPFC). Additionally, 20 Hz rTMS produced largepositive hemodynamic responses over the motor-related cortex, especially the right premotor cortex (R-PreM) and right primary sensorimotor cortex (PSMC). The current findings suggested that fNIRS can be used as a promising tool for evaluating the effects of rTMS in patients with DOC. Moreover, it provides useful guidance for the personalized design of rTMS parameters in a clinical environment.

This pilot study used functional near-infrared spectroscopy (fNIRS) to examine brain activity in selected regions of the left motor and sensory cortex while doing swallowing-related tasks. Specifically, differences in cortical activation during normal saliva swallows, effortful swallows, and tongue pressing were investigated. Nine healthy, right-handed adults (5 female, 4 male; Age: 22-30 years) were recruited. The tasks included were (1) normal saliva swallowing, (2) effortful saliva swallowing, and (3) lingual pressing against the palate. Each task was completed three times in a block, for a total of five blocks. Blocks were randomized and presented with set time intervals using PsychoPy. Motor activity was highest during effortful swallows, followed by normal swallows, and lingual presses. Activation in the sensory region was not significantly different across tasks; however, effortful swallows elicited the highest mean peak activation. Our findings suggest that fNIRS can be a viable imaging method used to examine differences in cortical activity in the context of swallowing. Its applicability in future dysphagia research should be explored.

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that may persist into adulthood, with no established objective diagnostic tool yet. This study aims to propose a multimodal objective assessment tool involving clinical assessments, functional neuroimaging, and oculomotricity measurement for ADHD in young adults.

Seventy-one medication-naïve patients and 71 healthy controls (HCs) aged 18 to 28 underwent clinical interviews, Conners' Adult ADHD Rating Scale (CAARS) questionnaire, functional near-infrared spectroscopy (fNIRS), oculomotricity task, and Conners' Continuous Performance Task (CPT) 3rd edition. Student's t-tests with Bonferroni's correction were performed to compare the performance between groups, and logistic regression was used for classification.

ADHD patients had significantly lower frontal hemodynamic response during verbal fluency task (VFT) (P = 0.0003), more anticipatory eye movements during overlap task (P = 0.0006), higher latency (P < 0.0001), anticipatory (P < 0.0001), and errors (P < 0.0001) during anti-saccade task, as well as higher commission errors (P < 0.0001) and standard deviation in hit reaction time (HRT) (P = 0.0018). The multivariate logistic regression model featuring these seven parameters from the three objective tests (fNIRS-VFT, oculomotricity, and CPT) yielded an area under the receiver operating characteristic curve (AUC) value of 0.892 (95% confidence interval (CI): 0.840-0.944), with sensitivity and specificity of 80.28% and 84.51%, respectively.

This multimodal assessment offered an accurate diagnostic tool for ADHD in young adults and laid the foundation for future machine-learning approaches.

In recent years, functional near-infrared spectroscopy (fNIRS) has gained increasing attention in the field of neurofeedback. However, there is a lack of freely accessible tools for research in this area that reflect the state of the art in research and technology.

To address this need, we introduce Non-commercial Interface for Neuro-Feedback Acquisitions (NINFA), a user-friendly and flexible freely available neurofeedback application for real-time fNIRS, which is also open to other modalities such as electroencephalography (EEG).

NINFA was developed in MATLAB and the lab streaming layer connection offers maximum flexibility in terms of combination with different fNIRS or EEG acquisition software and hardware.

The user-friendly interface allows measurements without requiring programming expertise. New neurofeedback protocols can be easily created, saved, and retrieved. We provide an example code for real-time data preprocessing and visual feedback; however, users can customize or expand it with appropriate programming skills.

NINFA enables real-time recording, analysis, and feedback of brain signals. We were able to demonstrate the stability and reliability of the computational performance of preprocessing and analysis methods in the current version. NINFA is intended as an application that can, should, and may evolve with the help of contributions from the community.

Visuospatial working memory capacity is crucial for daily life and various cognitive processes. Previous studies have shown that physical training not only improves physical fitness but also visual visuospatial working memory capacity. However, few studies have explored visuospatial working memory improvement and brain plasticity changes with long-term volleyball exercise. Therefore, the purpose of this study was to gain insight into whether there is a relationship between long-term volleyball practice and visuospatial working memory and the effects on the prefrontal lobes of the brain.

Neural correlates of visuospatial working memory in elite (n = 23; raining age mean: 8.27 ± 1.75 years; age: 21.07 ± 1.58 years) and novice (n = 23; raining age mean: 1.81 ± 0.56 years; age: 20.53 ± 1.36 years) volleyball athletes are examined to uncover potential skill-based differences. Functional near-infrared spectroscopy (fNIRS) data from 46 participants performing visuospatial working memory test reveal compelling results.

Compared with the novice group, the experts showed a higher accuracy rate (ACC) (p = 0.021) and shorter reaction time (RT) (p = 0.019) in the visuospatial working memory test. fNIRS data showed increased oxygen activation in the right dorsolateral prefrontal lobe (p < 0.05) and the right frontal region (p < 0.05).

Studies have shown that long-term volleyball training can significantly enhance individuals' visuospatial working memory capacity. This enhancement was mainly reflected in the fact that athletes who participated in long-term volleyball training demonstrated faster operational processing speed and higher accuracy in visuospatial working memory tasks, and plasticity changes in dorsolateral prefrontal and prefrontal pole regions. We also found no significant linear relationship between specific brain activation and behavioral performance in expert athletes.

This study aimed to explore the brain activity characteristics of individuals with Internet Gaming Disorder (IGD) during mobile gameplay, focusing on neural responses to positive and negative game events. The findings may enhance our understanding of the neural mechanisms underlying IGD.

Functional near-infrared spectroscopy (fNIRS) was employed to measure hemodynamic responses (HbO/HbR) in the prefrontal cortex of both IGD participants and recreational gaming users (RGU), during solo and multiplayer mobile gameplay.

In solo mode, IGD participants exhibited stronger activation in the dorsolateral prefrontal cortex (dLPFC), frontopolar area (FPA), orbitofrontal cortex (OFC) in response to positive events compared to RGU. Negative events led to reduced activation in the FPA among IGD participants. In multiplayer mode, IGD participants displayed lower activation in the dLPFC and ventrolateral prefrontal cortex (vLPFC), although overall brain response trends to positive and negative events were similar between IGD and RGU.

This study suggests that individuals with IGD exhibit heightened sensitivity to rewards and diminished sensitivity to losses, along with potential impairments in the executive control network. These results contribute to a better understanding of the neural mechanisms of IGD and offer insights for developing targeted interventions aimed at addressing abnormal reward and loss processing.

Many patients with coronavirus disease 2019 (COVID-19) may experience emotional issues and cognitive impairment. However, it remains unclear whether the brain mediates the impact of COVID-19 on the emergence of psychopathological symptoms. It remains unclear whether anxiety and depression are caused by stressors or viral infection.

To use functional near-infrared spectroscopy (fNIRS) to detect cortical hemodynamic changes in patients with COVID-19 and their relationship with mental symptoms (mainly depression and anxiety), to investigate whether COVID-19 causes these changes by affecting brain function.

A total of 58 subjects, comprising 29 patients with first acute COVID-19 infection and 29 healthy controls without COVID-19 infection and without anxiety or depression were recruited. Then cortical activation during the performance of the verbal fluency test (VFT) and brain connectivity during the resting state (rs) were evaluated by 53-channel fNIRS. For the COVID-19-infected group, Patient Health Questionnaire-9 (PHQ-9) and General Anxiety Disorder-7 (GAD-7) were used to assess the emotional state before fNIRS measures.

For the rs, compared to the uninfected group, the infected group exhibited lower rs functional connectivity (FC) in the dorsolateral prefrontal cortex (DLPFC), which was correlated with both the PHQ score and GAD score. During the VFT, the infected group exhibited significantly lower cortical activation than the uninfected group in both Broca-left and Broca-right. Besides, the integral value in the DLPFC-L showed a significant negative correlation with the PHQ-9 score during the VFT in the infected group.

There were significant differences in the bilateral Broca area and DLPFC between the COVID-19-infected and uninfected groups, which may be the reason why COVID-19 infection impairs cognitive function and language function and leads to psychiatric symptoms. In addition, the rsFC in patients with COVID-19 was positively correlated with the severity of depression and anxiety, which may be related to the fact that the mental symptoms of patients with COVID-19 are characterized by depression and anxiety, rather than depression or anxiety alone. Our study provides evidence that the psychological and emotional issues caused by COVID-19 are not only due to external social factors but also involve more direct brain neural mechanisms and abnormal neural circuits, which also provide insights into the future treatment and prognosis of individuals with COVID-19.

Understanding the intricate functions of the human brain requires multimodal approaches that integrate complementary neuroimaging techniques. This review systematically examines the integration of functional magnetic resonance imaging (fMRI) and functional near-infrared spectroscopy (fNIRs) in brain functional research, addressing their synergistic potential, methodological advancements, clinical and neuroscientific applications, and persistent challenges. We conducted a comprehensive literature review of 63 studies (from PubMed and Web of Science up to September 2024) using keyword combinations such as fMRI, fNIRs, and multimodal imaging. Our analysis reveals three key findings: (1) Methodological Synergy: Combining fMRI's high spatial resolution with fNIRs's superior temporal resolution and portability enables robust spatiotemporal mapping of neural activity, validated across motor, cognitive, and clinical tasks. Additionally, this study examines experimental paradigms and data processing techniques essential for effective multimodal neuroimaging. (2) Applications: The review categorizes integration methodologies into synchronous and asynchronous detection modes, highlighting their respective applications in spatial localization, validation of efficacy, and mechanism discovery. Synchronous and asynchronous integration modes have advanced research in neurological disorders (e.g., stroke, Alzheimer's), social cognition, and neuroplasticity, while novel hyperscanning paradigms extend applications to naturalistic, interactive settings. (3) Challenges: Hardware incompatibilities (e.g., electromagnetic interference in MRI environments), experimental limitations (e.g., restricted motion paradigms), and data fusion complexities hinder widespread adoption. The future direction emphasizes hardware innovation (such as fNIR probe compatible with MRI), standardized protocol and data integration driven by machine learning, etc. to solve the depth limitation of fNIR and infer subcortical activities. This synthesis underscores the transformative potential of fMRI-fNIRs integration in bridging spatial and temporal gaps in neuroimaging, while enhancing diagnostic and therapeutic strategies and paving the way for future innovations in brain research.

The act of performing music may induce a specific state of mind, musicians potentially becoming immersed and detached from the rest of the world. May this be measured? Does this state of mind change based on repetition? In collaboration with Stavanger Symphony Orchestra (SSO), we developed protocols to investigate ongoing changes in the brain activation of a first violinist and a second violinist in real time during seven sequential, public concerts using functional near-infrared spectroscopy (fNIRS). Using wireless fNIRS systems (Brite MKII) from Artinis, we measured ongoing hemodynamic changes and projected the brain activation to the audience through the software OxySoft 3.5.15.2. We subsequently developed protocols for further analyses through the Matlab toolboxes Brainstorm and Homer2/Homer3. Our developed protocols demonstrate how one may use "functional dissection" to imply how the state of mind of musicians may alter while performing their art. We focused on a subset of cortical regions in the right hemisphere, but the current study demonstrates how fNIRS may be used to shed light on brain dynamics related to producing art in ecological and natural contexts on a general level, neither restricted to the use of musical instrument nor art form.

Functional Near-Infrared Spectroscopy (fNIRS) enables neuroimaging in scenarios where other modalities are less suitable, such as during motion tasks or in low-resource environments. Sparse fNIRS arrays with 30mm channel spacing are widely used but have limited spatial resolution. High-density (HD) arrays with overlapping, multi-distance channels improve sensitivity and localization but increase costs and setup times. A statistical comparison of HD and sparse arrays is needed for evaluating the benefits and trade-offs of HD arrays.

This study provides a statistical comparison of HD and sparse fNIRS performance to inform array selection in future research.

We measured prefrontal cortex (PFC) activation during congruent and incongruent Word-Color Stroop (WCS) tasks using both Sparse and HD arrays for 17 healthy adult participants, comparing dorsolateral PFC channel and image results at the group level.

While both arrays detected activation in channel space during incongruent WCS, channel and image space results demonstrated superior localization and sensitivity with the HD array for all WCS.

Sparse channel data may suitably detect activation from cognitively demanding tasks, like incongruent WCS. However, the HD array outperformed Sparse in detecting and localizing brain activity in image space, particularly during lower cognitive load tasks, making them more suitable for neuroimaging applications.

Cognitive dysfunction in hemodialysis patients is associated with a decrease in regional cerebral oxygenation (rSO2). Intradialytic exercise improves cognitive function; nonetheless, the acute effect of intradialytic exercise on cerebral circulation remains unknown. This study aimed to evaluate the acute effect of intradialytic exercise on rSO2 during hemodialysis.

This single-center, open-label, randomized crossover trial included 20 hemodialysis patients. Patients received the control condition as usual care and the intradialytic exercise condition in random order. The intradialytic exercise condition involved the performance of anaerobic threshold–intensity interval exercise for 35 minutes. Cerebral oxygenation (rSO2, oxygenated hemoglobin, deoxygenated hemoglobin, and total hemoglobin) in the prefrontal cortex was measured using near-infrared spectroscopy during hemodialysis. Cardiovascular responses, including the heart rate, cardiac index, mean arterial pressure, and blood gas, were also assessed. The two conditions were compared using two-way repeated-measures analysis of variance.

The analysis included 16 patients, four of whom were excluded because of artifacts in the cerebral oxygenation data. The rSO2 (P < 0.001), oxygenated hemoglobin (P < 0.001), and total hemoglobin (P = 0.004) showed significant interactions and were increased at end of exercise (rSO2, 1.3%; 95% confidence interval [CI], 0.5 to 2.1; oxygenated hemoglobin, 0.01 mM; 95% CI, 0.00 to 0.02; total hemoglobin, 0.01 mM; 95% CI, 0.00 to 0.03) and 15 minutes after exercise (rSO2, 1.1%; 95% CI, 0.2 to 2.0; oxygenated hemoglobin, 0.01 mM; 95% CI, 0.00 to 0.03; total hemoglobin, 0.02 mM; 95% CI, 0.00 to 0.03) in the intradialytic exercise condition compared with the control condition. The rSO2 at the end of hemodialysis in the control condition was significantly decreased compared with that during predialysis (−1.5%; 95% CI, −2.7 to −0.3), but not in the intradialytic exercise condition (−1.2%; 95% CI, −2.8 to 0.5).

Intradialytic exercise significantly increased rSO2 during and after exercise and improved rSO2 to the same extent as predialysis.

Cognitive impairment refers to the impairment of higher brain functions such as perception, thinking or memory that affects the individual's ability to perform daily or social activities. Studies have found that changes in neuronal activity during tasks in patients with cognitive impairment are closely related to changes in cerebral cortical hemodynamics. Functional near-infrared spectroscopy is an indirect method to measure neural activity based on changes in blood oxygen concentration in the cerebral cortex. Due to its strong anti-motion interference, high compatibility, and almost no restriction on participants and environment, it has shown great potential in the research field of cognitive impairment. Recognizing these benefits, this comprehensive review systematically elucidates the rationale, historical development, advantages and disadvantages of functional near-infrared spectroscopy, and also discusses the applications of combining functional near-infrared spectroscopy with other detection techniques. Additionally, this review summarized how functional near-infrared spectroscopy can be applied to cognitive impairment caused by different diseases, ultimately aiding the study of neural mechanisms of cognitive activities, which is crucial for the diagnosis, differentiation and treatment of cognitive impairment.

Maintaining balance while simultaneously performing other tasks is common during everyday activities. However, this dual-tasking (DT) divides attention and increases cognitive demand, which can be detrimental to stability in older adults. It is unknown if the focus of attention influences how a dual-task affects balance and whether this is detectable in middle-aged adults. This study investigates the effect of dual-task and attentional focus on prefrontal cortex (PFC) activity in young (YA) and middle-aged (MA) adults using functional-near infrared spectroscopy. Blood oxygen level of the PFC was measured during a quiet standing cognitive-motor dual-task where MA (n = 15, mean age 57.2 ± 4.8 years, 5 female) and YA (n = 20, mean age 24.9 ± 4.7 years, 9 female) stood on a forceplate while either fixating their gaze on a target ('fixed') or viewing their real-time postural oscillations in the anteroposterior direction ('sway') with and without serial 7 subtractions. It was expected that the MA group would show higher PFC activity, larger COP excursions, and poorer performance during DT than the YA group. PFC activity was larger during DT and during the fixed condition but did not differ between groups. COP excursion was also greater when attention was 'fixed' and was consistently larger in MA. MA drove a positive correlation between PFC activity and COP excursion during DT indicative of a higher attentional demand during distraction. Taken together, this study suggests that PFC processing and posture control are different in middle aged adults compared to young adults.