Instantaneous effects of prefrontal transcranial magnetic stimulation on brain oxygenation: A systematic review

This systematic review investigated how prefrontal transcranial magnetic stimulation (TMS) immediately influences neuronal excitability based on oxygenation changes measured by functional magnetic resonance imaging (fMRI) or functional near-infrared spectroscopy (fNIRS). A thorough understanding of TMS-induced excitability changes may enable clinicians to proactively adjust TMS parameters and optimize treatment plans. Five databases were searched for human studies evaluating brain excitability using concurrent TMS/fMRI or TMS/fNIRS. Thirty-seven studies (13 concurrent TMS/fNIRS studies, 24 concurrent TMS/fMRI studies) were included in a qualitative synthesis. Despite methodological inconsistencies, a distinct pattern of activated nodes of the frontoparietal central executive network, the cingulo-opercular salience network and the default-mode network emerged. Nodes included the prefrontal cortex (especially dorsolateral prefrontal cortex), insula cortex, striatal regions (especially caudate, putamen), anterior cingulate cortex and thalamus. Meanwhile, high-frequency repetitive TMS most consistently induced expected facilitatory effects in these brain regions. However, varied stimulation parameters (e.g., intensity, coil orientation, target sites) and the inter and intra-individual variability of brain state contribute to the observed heterogeneity of target excitability and co-activated regions. Given the considerable methodological and individual variability across the limited evidence, conclusions should be drawn with caution.

A simultaneous EEG-fNIRS dataset of the visual cognitive motivation study in healthy adults

This article described a publicly available dataset of the visual cognitive motivation study in healthy adults. To gain an in-depth understanding and insights into motivation, Electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) were measured simultaneously at shared locations while participants performed a visual cognitive motivation task. The participants' choices in the cognitive motivation task were recorded. The effects of their motivation were identified in the recognition test afterward. This dataset comprised EEG and fNIRS data from sixteen healthy adults (age: 21- 37 years; 14 males and 2 females) during the cognitive motivation task with visual scenic stimuli. In addition, the motivation and the corresponding motivation effect were also provided. This dataset provides understanding and analyzing opportunities for the process of attention and decision while the brain undergoes an induced motivated state and its effect on the recognition performance.

Efficacy and executive function of solution-focused brief therapy on adolescent depression

Objective

To investigate the efficacy and impact on executive function of Solution-Focused Brief Therapy (SFBT) in treating Major Depressive Disorder (MDD) in adolescents.

Methods

A total of 129 adolescents diagnosed with MDD were enrolled in the study. Out of these, 28 adolescents were assigned to the SFBT group, while 25 were part of the Active Control group (AC group), receiving psychodynamic psychotherapy. Executive function, depressive and anxiety symptoms were assessed at baseline, at the time of the third intervention, the sixth intervention, and the 10th intervention.

Results

After the third intervention, the scores of the Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7) of the participants in the SFBT group decreased significantly, which had the cumulative effect at the 6th and 10th interventions. The verbal fluency task (VFT) performances of the SFBT group participants yielded significantly higher scores after the third intervention and remained increasing at the 6th and 10th interventions. The AC group steadily decreased after the intervention. Analysis of functional near-infrared spectroscopy (fNIRS) data revealed a progressive and significant increase in the average oxyhemoglobin (oxy-Hb) levels in the dorsolateral prefrontal cortex (DLPFC) in the SFBT group compared to the AC group after the 10th intervention.

Conclusions

SFBT might improve depressive and anxiety symptoms as well as executive function of adolescent depression.

Clinical trial registration

https://www.chictr.org.cn, identifier ChiCTR2300067909.

Rock music improvisation shows increased activity in Broca's area and its right hemisphere homologue related to spontaneous creativity

OBJECTIVE

The neural correlates of creativity are not well understood. Using an improvised guitar task, we investigated the role of Broca's area during spontaneous creativity, regardless of individual skills, experience, or subjective feelings.

RESULTS

Twenty guitarists performed improvised and formulaic blues rock sequences while hemodynamic responses were recorded using functional near-infrared spectroscopy. We identified a new significant response in Broca's area (Brodmann area [BA] 45L) and its right hemisphere homologue during improvised playing but not during formulaic playing. Our results indicate that bilateral BA45 activity is common during creative processes that involve improvisation across all participants, regardless of subjective feelings, skill, age, difficulty, history, or amount of practice. While our previous results demonstrated that the modulation of the neural network according to the subjectively experienced level of creativity relied on the degree of deactivation in BA46L, our current results independently show a common concurrent activity in BA45 in all participants. We suggest that this is related to the sustained execution of improvisation in "motor control," analogous to motor planning in speech control.

Relationship between accelerometer-measured sleep duration and Stroop performance: a functional near-infrared spectroscopy study among young adults

Objectives

Short sleep is becoming more common in modern society. This study aimed to explore the relationship between accelerometer-measured sleep duration and cognitive performance among young adults as well as the underlying hemodynamic mechanisms.

Methods

A total of 58 participants were included in this study. Participants were asked to wear an ActiGraph GT3X+ accelerometer to identify their sleep duration for 7 consecutive days. Cognitive function was assessed by the Stroop test. Two conditions, including the congruent and incongruent Stroop, were set. In addition, stratified analyses were used to examine sensitivity. 24-channel functional near-infrared spectroscopy (fNIRS) equipment was applied to measure hemodynamic changes of the prefrontal cortex (PFC) during cognitive tasks.

Results

Results showed that sleep duration was positively associated with accuracy of the incongruent Stroop test (0.001 (0.000, 0.002), p = 0.042). Compared with the regular sleep (≥7 h) group, lower accuracy of the incongruent Stroop test (-0.012 (-0.023, -0.002), p = 0.024) was observed in the severe short sleep (<6 h). Moreover, a stratified analysis was conducted to examining gender, age, BMI, birthplace, and education's impact on sleep duration and the incongruent Stroop test accuracy, confirming a consistent correlation across all demographics. In the severe short sleep group, the activation of left middle frontal gyri and right dorsolateral superior frontal gyri were negatively associated with the cognitive performance.

Conclusions

This study emphasized the importance of maintaining enough sleep schedules in young college students from a fNIRS perspective. The findings of this study could potentially be used to guide sleep time in young adults and help them make sleep schemes.

Prefrontal cortex activation while walking did not change but gait speed improved after a randomized physical therapy intervention

BACKGROUND

Higher prefrontal cortex (PFC) activation while walking may indicate reduced gait automaticity.

AIM

We examine whether PFC activation during walking improves after training in older adults at risk for mobility disability.

METHODS

Forty-two adults aged ≥ 65 participated in a randomized clinical trial (NCT026637780) of a 12-week timing and coordination physical therapy intervention to improve walking (n = 20 intervention, n = 22 active control). PFC activation was measured by functional near-infrared spectroscopy (fNIRS) during four walking tasks over 15 m, each repeated 4 times: even surface walking, uneven surface walking, even dual-task, uneven dual-task; dual-task was reciting every other letter of the alphabet while walking. Gait speed and rate of correct letter generation were recorded. Linear mixed models tested between arm differences in change of fNIRS, gait speed, and letter generation from baseline to follow-up (12-week, 24-week, and 36-week).

RESULTS

Intervention arms were similar in mean age (74.3 vs. 77.0) and baseline gait speed (0.96 vs. 0.93 m/s). Of 24 comparisons of between arm differences in the fNIRS signals, only two were significant which were not supported by differences at other follow-up times or on other tasks. Gait speed, particularly during dual-task conditions, and correct letter generation did improve post-intervention but improvements did not differ by arm.

DISCUSSION AND CONCLUSIONS

After training, PFC activation during walking generally did not improve and did not differ by intervention arm. Improvements in gait speed without increased PFC activation may point toward more efficient neural control of walking.

Brain activation during standing balance control in dual-task paradigm and its correlation among older adults with mild cognitive impairment: a fNIRS study

BACKGROUND

This study aimed to compare the balance ability and functional brain oxygenation in the prefrontal cortex (PFC) among older adults with mild cognitive impairment (MCI) under single and dual tasks, and also investigate their relationship. Neural regulatory mechanisms of the brain in the MCI were shed light on in balance control conditions.

METHODS

21 older adults with MCI (female = 12, age: 71.19 ± 3.36 years) were recruited as the experimental group and 19 healthy older adults (female = 9, age: 70.16 ± 4.54 years) as the control group. Participants completed balance control of single task and dual task respectively. Functional near-infrared spectroscopy (fNIRS) and force measuring platform are used to collect hemodynamic signals of the PFC and center of pressure (COP) data during the balance task, respectively.

RESULTS

The significant Group*Task interaction effect was found in maximal displacement of the COP in the medial-lateral (ML) direction (D-ml), 95% confidence ellipse area (95%AREA), root mean square (RMS), the RMS in the ML direction (RMS-ml), the RMS in the anterior-posterior (AP) direction (RMS-ap), sway path (SP), the sway path in the ML direction (SP-ml), and the sway path in the AP direction (SP-ap). The significant group effect was detected for five regions of interest (ROI), namely the left Brodmann area (BA) 45 (L45), the right BA45 (R45), the right BA10 (R10), the left BA46 (L46), and the right BA11 (R11). Under single task, maximal displacement of the COP in the AP direction (D-ap), RMS, and RMS-ap were significantly negatively correlated with R45, L45, and R11 respectively. Under dual task, both RMS and 95%AREA were correlated positively with L45, and both L10 and R10 were positively correlated with RMS-ap.

CONCLUSION

The MCI demonstrated worse balance control ability as compared to healthy older adults. The greater activation of PFC under dual tasks in MCI may be considered a compensatory strategy for maintaining the standing balance. The brain activation was negatively correlated with balance ability under single task, and positively under dual task.

TRIAL REGISTRATION

ChiCTR2100044221 , 12/03/2021.

Interpretable deep learning model for major depressive disorder assessment based on functional near-infrared spectroscopy

BACKGROUND

Major depressive disorder (MDD) affects a substantial number of individuals worldwide. New approaches are required to improve the diagnosis of MDD, which relies heavily on subjective reports of depression-related symptoms.

AIM

Establish an objective measurement and evaluation of MDD.

METHODS

Functional near-infrared spectroscopy (fNIRS) was used to investigate the brain activity of MDD patients and healthy controls (HCs). Leveraging a sizeable fNIRS dataset of 263 HCs and 251 patients with MDD, including mild to moderate MDD (mMDD; n = 139) and severe MDD (sMDD; n = 77), we developed an interpretable deep learning model for screening MDD and staging its severity.

RESULTS

The proposed deep learning model achieved an accuracy of 80.9% in diagnostic classification and 78.6% in severity staging for MDD. We discerned five channels with the most significant contribution to MDD identification through Shapley additive explanations (SHAP), located in the right medial prefrontal cortex, right dorsolateral prefrontal cortex, right superior temporal gyrus, and left posterior superior frontal cortex. The findings corresponded closely to the features of haemoglobin responses between HCs and individuals with MDD, as we obtained a good discriminative ability for MDD using cortical channels that are related to the disorder, namely the frontal and temporal cortical channels with areas under the curve of 0.78 and 0.81, respectively.

CONCLUSION

Our study demonstrated the potential of integrating the fNIRS system with artificial intelligence algorithms to classify and stage MDD in clinical settings using a large dataset. This approach can potentially enhance MDD assessment and provide insights for clinical diagnosis and intervention.

fNIRS-based graph frequency analysis to identify mild cognitive impairment in Parkinson's disease

BACKGROUND

Early identification of mild cognitive impairment (MCI) is essential for its treatment and the prevention of dementia in Parkinson's disease (PD). Existing approaches are mostly based on neuropsychological assessments, while brain activation and connection have not been well considered.

NEW METHOD

This paper presents a neuroimaging-based graph frequency analysis method and the generated features to quantify the brain functional neurodegeneration and distinguish between PD-MCI patients and healthy controls. The Stroop color-word experiment was conducted with 20 PD-MCI patients and 34 healthy controls, and the brain activation was recorded with functional near-infrared spectroscopy (fNIRS). Then, the functional brain network was constructed based on Pearson's correlation coefficient calculation between every two fNIRS channels. Next, the functional brain network was represented as a graph and decomposed in the graph frequency domain through the graph Fourier transform (GFT) to obtain the eigenvector matrix. Total variation and weighted zero crossings of eigenvectors were defined and integrated to quantify functional interaction between brain regions and the spatial variability of the brain network in specific graph frequency ranges, respectively. After that, the features were employed in training a support vector machine (SVM) classifier.

RESULTS

The presented method achieved a classification accuracy of 0.833 and an F1 score of 0.877, significantly outperforming existing methods and features.

COMPARISON WITH EXISTING METHODS

Our method provided improved classification performance in the identification of PD-MCI.

CONCLUSION

The results suggest that the presented graph frequency analysis method well identify PD-MCI patients and the generated features promise functional brain biomarkers for PD-MCI diagnosis.

Mother-infant social gaze dynamics relate to infant brain activity and word segmentation

The 'social brain', consisting of areas sensitive to social information, supposedly gates the mechanisms involved in human language learning. Early preverbal interactions are guided by ostensive signals, such as gaze patterns, which are coordinated across body, brain, and environment. However, little is known about how the infant brain processes social gaze in naturalistic interactions and how this relates to infant language development. During free-play of 9-month-olds with their mothers, we recorded hemodynamic cortical activity of ´social brain` areas (prefrontal cortex, temporo-parietal junctions) via fNIRS, and micro-coded mother's and infant's social gaze. Infants' speech processing was assessed with a word segmentation task. Using joint recurrence quantification analysis, we examined the connection between infants' ´social brain` activity and the temporal dynamics of social gaze at intrapersonal (i.e., infant's coordination, maternal coordination) and interpersonal (i.e., dyadic coupling) levels. Regression modeling revealed that intrapersonal dynamics in maternal social gaze (but not infant's coordination or dyadic coupling) coordinated significantly with infant's cortical activity. Moreover, recurrence quantification analysis revealed that intrapersonal maternal social gaze dynamics (in terms of entropy) were the best predictor of infants' word segmentation. The findings support the importance of social interaction in language development, particularly highlighting maternal social gaze dynamics.

Hemodynamic signal changes during volitional swallowing in dysphagia patients with different unilateral hemispheric stroke and brainstem stroke: A near-infrared spectroscopy study

BACKGROUND AND OBJECTIVES

Strokes will result in decreased in cortical excitability and changed in the balance between the affected and unaffected hemispheres. Previous studies have focused on cortical changes in healthy subjects during swallowing, while they remain unknown in patients with stroke at different locations. Thus, the purpose of this study was to research cortical activation patterns of swallowing in patients with dysphagia and healthy subjects by the functional near-infrared spectroscopy (fNIRS). We also focus on the comparability of brain activation areas associated with swallowing between patients with different stroke locations and healthy subjects.

METHODS

total of 104 participants were invited to our study, involving 86 patients with dysphagic unilateral hemispheric stroke and 18 age and sex matched healthy controls. The stroke patients were categorized into patients with left unilateral stroke lesions (n = 30), patients with right unilateral stroke lesions (n = 32) and patients with brainstem injury (n = 24) according to different stroke sites. All patients underwent a series of clinical swallowing function assessments, such as the Fiberoptic endoscopic dysphagia severity scale (FEDSS), penetration-aspiration scale (PAS) of Rosenbek, the gugging swallowing screen (GUSS) and the functional oral Intake scale (FOIS) after informed consent has been signed. All participants received the fNIRS system assessment.

RESULTS

The results showed that extensive areas of the cerebral cortex activated during the swallowing tasks in healthy participants (P < FDR 0.05). For patients with left unilateral stroke lesions, the HbO concentration were strongest over the right hemisphere (P < FDR 0.05). In addition, a less severe activation was also observed in the left hemisphere. Comparable to patients with left unilateral stroke lesions, the strongest activation during swallowing task were found in the left hemisphere in patients with right unilateral stroke lesions (P < FDR 0.05). Similarly, the right hemisphere also has activated less. In contrast, patients with brain stem injury showed more bilaterally activation patterns.

CONCLUSION

Our finding states that cortical activation areas differ between patients with different stroke locations and healthy subjects during swallowing. There was a more bilateral activation in healthy participants and patients with lesions in the brainstem while more cortical activation in unaffected hemisphere in patients with unilateral hemispheric stroke. It also provides a basis for the future treatment of dysphagia after stroke.

Mild exercise improves executive function with increasing neural efficiency in the prefrontal cortex of older adults

This study examined whether a 3-month mild-exercise intervention could improve executive function in healthy middle-aged and older adults in a randomized control trial. Ultimately, a total of 81 middle-aged and older adults were randomly assigned to either an exercise group or a control group. The exercise group received 3 months of mild cycle exercise intervention (3 sessions/week, 30-50 min/session). The control group was asked to behave as usual for the intervention period. Before and after the intervention, participants did color-word matching Stroop tasks (CWST), and Stroop interference (SI)-related reaction time (RT) was assessed as an indicator of executive function. During the CWST, prefrontal activation was monitored using functional near-infrared spectroscopy (fNIRS). SI-related oxy-Hb changes and SI-related neural efficiency (NE) scores were assessed to examine the underlying neural mechanism of the exercise intervention. Although the mild-exercise intervention significantly decreased SI-related RT, there were no significant effects of exercise intervention on SI-related oxy-Hb changes or SI-related NE scores in prefrontal subregions. Lastly, changes in the effects of mild exercise on NE with advancing age were examined. The 81 participants were divided into two subgroups (younger-aged subgroup [YA], older-aged subgroup [OA], based on median age [68 years.]). Interestingly, SI-related RT significantly decreased, and SI-related NE scores in all ROIs of the prefrontal cortex significantly increased only in the OA subgroup. These results reveal that a long-term intervention of very light-intensity exercise has a positive effect on executive function especially in older adults, possibly by increasing neural efficiency in the prefrontal cortex.

A comprehensive research setup for monitoring Alzheimer's disease using EEG, fNIRS, and Gait analysis

Alzheimer's disease (AD) has a detrimental impact on brain function, affecting various aspects such as cognition, memory, language, and motor skills. Previous research has dominantly used electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) to individually measure brain signals or combine the two methods to target specific brain functions. However, comprehending Alzheimer's disease requires monitoring various brain functions rather than focusing on a single function. This paper presents a comprehensive research setup for a monitoring platform for AD. The platform incorporates a 32-channel dry electrode EEG, a custom-built four-channel fNIRS, and gait monitoring using a depth camera and pressure sensor. Various tasks are employed to target multiple brain functions. The paper introduced the detailed instrumentation of the fNIRS system, which measures the prefrontal cortex, outlines the experimental design targeting various brain functioning programmed in BCI2000 for visualizing EEG signals synchronized with experimental stimulation, and describes the gait monitoring hardware and software and protocol design. The ultimate goal of this platform is to develop an easy-to-perform brain and gait monitoring method for elderly individuals and patients with Alzheimer's disease.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13534-023-00306-7.

Covariate-guided Bayesian mixture of spline experts for the analysis of multivariate high-density longitudinal data

With rapid development of techniques to measure brain activity and structure, statistical methods for analyzing modern brain-imaging data play an important role in the advancement of science. Imaging data that measure brain function are usually multivariate high-density longitudinal data and are heterogeneous across both imaging sources and subjects, which lead to various statistical and computational challenges. In this article, we propose a group-based method to cluster a collection of multivariate high-density longitudinal data via a Bayesian mixture of smoothing splines. Our method assumes each multivariate high-density longitudinal trajectory is a mixture of multiple components with different mixing weights. Time-independent covariates are assumed to be associated with the mixture components and are incorporated via logistic weights of a mixture-of-experts model. We formulate this approach under a fully Bayesian framework using Gibbs sampling where the number of components is selected based on a deviance information criterion. The proposed method is compared to existing methods via simulation studies and is applied to a study on functional near-infrared spectroscopy, which aims to understand infant emotional reactivity and recovery from stress. The results reveal distinct patterns of brain activity, as well as associations between these patterns and selected covariates.

Effects of transcranial magnetic stimulation on dynamic functional networks in stroke patients as assessed by functional near-infrared spectroscopy: a randomized controlled clinical trial

Studies have shown that there is heterogeneity in the efficacy bewteen the low-frequency (LF) and high-frequency (HF) repetitive transcranial magnetic stimulation (rTMS), but the neural mechanisms underlying the differences in efficacy remain unclear. This study aimed to investigate the specific effects of LF- and HF-rTMS on cortial functional network and the process of neural regulation. A total of sixty-eight patients with hemiplegic motor impairment after stroke were randomly allocated to one of three groups: the LF-rTMS, HF-rTMS, and sham groups. Tissue concentrations of oxyhaemoglobin and deoxyhaemoglobin oscillations in cerebral cortex regions were measured by functional near-infrared spectroscopy (fNIRS) in the resting and rTMS states. Four specific time-windows were divided from the trial duration to observe dynamic changes in cortical haemodynamic responses. Compared with sham, LF-rTMS significantly induced the activation of the contralesional superior frontal cortex and premotor cortex, and continuously regulated ipsilesional hemisphere functional networks in stroke patients. However, HF-rTMS did not induce a significant neurovascular coupling response. Our study provided evidence that LF- and HF-rTMS interventions induced different neurovascular coupling responses and demonstrated the cortical functional network change process of rTMS in specific time-windows. These findings may help to understand the differences in the efficacy of rTMS modalities.

The effects of palatinose on attention and cerebral blood flow in healthy adults: A randomized double-blind placebo-controlled crossover study

OBJECTIVE

The primary energy source for the brain is glucose, and a continuous supply is required for the brain to work longer. This study aimed to verify the effects of palatinose on attention and cerebral blood flow in healthy adults.

METHODS

This randomized, double-blind, placebo-controlled crossover study included 64 healthy Japanese adults. Participants performed the Digit Vigilance Task (DVT) 60 min pre-ingestion (14:00) and 0 (15:00), 60 (16:00), 120 (17:00), and 180 (18:00) min after ingestion of 10 g of either palatinose or glucose. Cerebral blood flow was measured using a wearable 2CH functional near-infrared spectrometer (fNIRS) during each DVT. The participants underwent the Uchida-Kraepelin (UK) test between each DVT to control for fatigue.

RESULTS

DVT reaction times with palatinose intake were significantly shorter than those with glucose intake at 16:00, 17:00, and 18:00 (p = 0.0015, p < 0.001, and p < 0.001, respectively). The change in cerebral blood flow as a function of total hemoglobin level was significantly higher in the palatinose group than in the glucose group (p = 0.018). Regarding the post-UK mood questionnaire, "physically fatigued" and "annoyed" were significantly lower in the palatinose intake group compared to the glucose intake group at 17:00 (p = 0.0445 and p = 0.0318, respectively). Furthermore, "physically fatigued" was significantly lower, and "seriously" was higher in the palatinose intake compared to the glucose intake group at 18:00 (p = 0.00652 and p < 0.001, respectively).

CONCLUSION

These findings suggest that 10 g of palatinose has favorable effects on attention and cerebral blood flow.

TRIAL REGISTRATION

UMIN000046182.

Neuroimaging, wearable sensors, and blood-based biomarkers reveal hyperacute changes in the brain after sub-concussive impacts

Impacts in mixed martial arts (MMA) have been studied mainly in regard to the long-term effects of concussions. However, repetitive sub-concussive head impacts at the hyperacute phase (minutes after impact), are not understood. The head experiences rapid acceleration similar to a concussion, but without clinical symptoms. We utilize portable neuroimaging technology - transcranial Doppler (TCD) ultrasound and functional near infrared spectroscopy (fNIRS) - to estimate the extent of pre- and post-differences following contact and non-contact sparring sessions in nine MMA athletes. In addition, the extent of changes in neurofilament light (NfL) protein biomarker concentrations, and neurocognitive/balance parameters were determined following impacts. Athletes were instrumented with sensor-based mouth guards to record head kinematics. TCD and fNIRS results demonstrated significantly increased blood flow velocity (p = 0.01) as well as prefrontal (p = 0.01) and motor cortex (p = 0.04) oxygenation, only following the contact sparring sessions. This increase after contact was correlated with the cumulative angular acceleration experienced during impacts (p = 0.01). In addition, the NfL biomarker demonstrated positive correlations with angular acceleration (p = 0.03), and maximum principal and fiber strain (p = 0.01). On average athletes experienced 23.9 ± 2.9 g peak linear acceleration, 10.29 ± 1.1 rad/s peak angular velocity, and 1,502.3 ± 532.3 rad/s2 angular acceleration. Balance parameters were significantly increased following contact sparring for medial-lateral (ML) center of mass (COM) sway, and ML ankle angle (p = 0.01), illustrating worsened balance. These combined results reveal significant changes in brain hemodynamics and neurophysiological parameters that occur immediately after sub-concussive impacts and suggest that the physical impact to the head plays an important role in these changes.

Prefrontal hemodynamic features of older adults with preserved visuospatial working memory function

Memory decline has been observed in the aging population and is a risk factor for the later development of dementia. Understanding how memory is preserved in older adults has been an important topic. The present study examines the hemodynamic features of older adults whose memory is comparable with that of young adults. In the present study, 45 younger and 45 older adults performed the visual memory task with various difficulty levels (i.e., the items to be remembered), and their cerebral hemodynamics at each level were measured by functional near-infrared spectroscopy (fNIRS). The results showed that older adults exhibited higher activation than younger adults under more difficult but not easier levels. In addition, older adults whose performance is comparable with that of young adults (i.e., being able to remember six items) showed more right-lateralized activation. However, those unable to do so showed more left-lateralized activation. The results suggested that high-performing older adults possess successful compensatory mechanisms by recruiting cognitive resources in a specialized brain region.

Intravesical Electrical Stimulation Improves Abnormal Prefrontal Brain Activity in Patients With Underactive Bladder: A Possible Central Mechanism

PURPOSE

The aim of this study was to explore the mechanisms of central brain action in patients with neurogenic underactive bladder (UAB) treated with intravesical electrical stimulation (IVES).

METHODS

We prospectively recruited patients with neurogenic UAB who chose to receive IVES treatment and healthy subjects (HS). At baseline, the following data were obtained: a 72-hour voiding diary; measurements of postvoid residual urine (PVR), voiding efficiency (VE) and first sensation of bladder filling (FS); American Urological Association Symptom Index Quality of Life (AUA-SI-QOL) scores, and functional near-infrared spectroscopy scans of the prefrontal cortex in the voiding stage. All UAB patients were re-evaluated for these indices after completing 4 weeks of IVES. A >50% improvement in PVR was defined as successful IVES treatment. Prefrontal activity was analyzed using the NIRS_KIT software, corrected with the false discovery rate (P<0.05). Statistical analysis was performed using IBM SPSS Statistics ver. 22.0, and P<0.05 was considered statistically significant.

RESULTS

Eighteen UAB patients and 16 HS were included. IVES treatment was successful in 11 UAB patients and failed in 7. The PVR, VE, 24-hour clean intermittent catheterization, FS volume, and AUA-SI-QOL scores of the UAB group significantly improved after successful IVES treatment. BA9 (right dorsolateral prefrontal cortex [DLPFC]) and BA10 (right frontal pole) were significantly activated after successful IVES, and no significant difference was found between the successful group and HS group after IVES. Before IVES, BA10 (right frontal pole) was significantly deactivated in the failed group compared with the successful group.

CONCLUSION

The possible central mechanism of IVES treatment for neurogenic UAB is that IVES reactivates the right DLPFC and right frontal pole.

Transcranial Alternating Current Stimulation in a Patient with Ataxia-Ocular Apraxia 2: a Case Report

Ataxia-ocular apraxia 2 (AOA2) is a rare neurodegenerative autosomal recessive disorder with no effective treatment. In this study, we present the case of a patient diagnosed with AOA2, who experienced walking instability and uncoordinated movement. The patient underwent transcranial alternating current stimulation (tACS) treatment for 4 weeks with follow-up after 1 month. The effectiveness of the treatment was evaluated using the International Cooperative Ataxia Rating Scale (ICARS), the Scale for the Assessment and Rating of Ataxia (SARA), the 9-Hole Peg Test (9HPT), and functional near-infrared spectroscopy (fNIRS). Following treatment, the patient's ataxia symptoms showed significant improvement and continued to be alleviated during the follow-up period, suggesting a lasting effect of tACS treatment. Our findings from this case study provide compelling evidence for the potential of tACS as a treatment option for AOA2.

Increased interbrain synchronization and neural efficiency of the frontal cortex to enhance human coordinative behavior: A combined hyper-tES and fNIRS study

Coordination is crucial for individuals to achieve common goals; however, the causal relationship between coordination behavior and neural activity has not yet been explored. Interbrain synchronization (IBS) and neural efficiency in cortical areas associated with the mirror neuron system (MNS) are considered two potential brain mechanisms. In the present study, we attempted to clarify how the two mechanisms facilitate coordination using hypertranscranial electrical stimulation (hyper-tES). A total of 124 healthy young adults were randomly divided into three groups (the hyper-tACS, hyper-tDCS and sham groups) and underwent modulation of the right inferior frontal gyrus (IFG) during functional near-infrared spectroscopy (fNIRS). Increased IBS of the PFC or neural efficiency of the right IFG (related to the MNS) was accompanied by greater coordination behavior; IBS had longer-lasting effects on behavior. Our findings highlight the importance of IBS and neural efficiency of the frontal cortex for coordination and suggest potential interventions to improve coordination in different temporal windows.

Assessing the impact of preferred web app-based music-listening on pain processing at the central nervous level in older black adults with low back pain: An fNIRS study

BACKGROUND

Low back pain (LBP) disproportionately affects older black adults, often leading to inadequate treatment due to clinician biases. Objective pain measures are imperative, and Functional Near-Infrared Spectroscopy (fNIRS) shows promise for pain detection.

AIM

To determine the impact of listening to home-based preferred web app-based music on underlying pain processing mechanisms at the central nervous level in older black adults aged ≥65 with LBP.

METHODS

Twenty older black adults with LBP listened to preferred music twice daily for four days using the MUSIC CARE® app. Neuroimaging data were collected using fNIRS. Data were transformed to changes in oxy-hemoglobin and deoxy-hemoglobin concentrations and analyzed.

RESULTS

Significant cortical activation pattern differences were observed between pre-and post-intervention scans, particularly in somatosensory regions. Post-intervention scans showed significantly reduced hemodynamic activities.

CONCLUSION

Preferred music listening has the potential to alleviate pain, and fNIRS emerges as a promising tool for exploring cortical-level pain-related neural circuits.

Modulating Cortical Hemodynamic Activity in Parkinson's Disease Using Focal Transcranial Direct Current Stimulation: A Pilot Functional Near-infrared Spectroscopy Study

Reduced thalamocortical facilitation of the motor cortex in PD leads to characteristic motor deficits such as bradykinesia. Recent research has highlighted improved motor function following tDCS, but a lack of neurophysiological evidence limits the progress of tDCS as an adjunctive therapy. Here, we tested the hypothesis that tDCS may modulate M1 hemodynamic activity in PD and healthy using functional near-infrared spectroscopy (fNIRS). In this randomized crossover experiment, fourteen PD and twelve healthy control participants attended three laboratory sessions and performed a regulated (3 Hz) right index finger tapping task before and after receiving tDCS. On each visit, participants received either anodal, cathodal, or sham tDCS applied over M1. Hemodynamic activity of M1 was quantified using fNIRS. Significant task related activity was observed in M1 and the inferior parietal lobe in PD and healthy (p < 0.05). PD additionally recruited the dorsal premotor cortex. During tDCS, while at rest, anodal and cathodal tDCS significantly increased the oxygenated hemoglobin concentration of M1 compared to sham (t62 = 4.09 and t62 = 4.25, respectively). Task related hemodynamic activity was unchanged following any tDCS intervention (p > 0.05). Task related hemodynamic activity of M1 is not modulated by tDCS in PD or healthy. During tDCS, both anodal and cathodal stimulation cause a significant increase of M1 oxygenation, the clinical significance of which remains to be clarified.

Neurophysiological and gait outcomes during a dual-task gait assessment in concussed adolescents

BACKGROUND

Gait deficits are common after concussion in adolescents. However, the neurophysiological underpinnings of these gait deficiencies are currently unknown. Thus, the goal of this study was to compare spatiotemporal gait metrics, prefrontal cortical activation, and neural efficiency between concussed adolescents several weeks from injury and uninjured adolescents during a dual-task gait assessment.

METHODS

Fifteen concussed (mean age[SD]: 17.4[0.6], 13 female, days since injury: 26.3[9.9]) and 17 uninjured adolescents (18.0[0.7], 10 female) completed a gait assessment with three conditions repeated thrice: single-task walking, single-task subtraction, and dual-task, which involved walking while completing a subtraction task simultaneously. Gait metrics were measured using an inertial sensor system. Prefrontal cortical activation was captured via functional near-infrared spectroscopy. Neural efficiency was calculated by relating gait metrics to prefrontal cortical activity. Differences between groups and conditions were examined, with corrections for multiple comparisons.

FINDINGS

There were no significant differences in gait metrics between groups. Compared to uninjured adolescents, concussed adolescents displayed significantly greater prefrontal cortical activation during the single-task subtraction (P = 0.01) and dual-task (P = 0.01) conditions with lower neural efficiency based on cadence (P = 0.02), gait cycle duration (P = 0.03), step duration (P = 0.03), and gait speed (P = 0.04) during the dual-task condition.

INTERPRETATION

Our findings suggest that several weeks after injury concussed adolescents demonstrate lower neural efficiency and display a cost to gait performance when cognitive demand is high, e.g., while multitasking, suggesting that the concussed adolescent brain is less able to compensate when attention is divided between two concurrent tasks.

Surface-based integration approach for fNIRS-fMRI reliability assessment

INTRODUCTION

Studies integrating functional near-infrared spectroscopy (fNIRS) with functional MRI (fMRI) employ heterogeneous methods in defining common regions of interest in which similarities are assessed. Therefore, spatial agreement and temporal correlation may not be reproducible across studies. In the present work, we address this issue by proposing a novel method for integration and analysis of fNIRS and fMRI over the cortical surface.

MATERIALS AND METHODS

Eighteen healthy volunteers (age mean±SD 30.55 ± 4.7, 7 males) performed a motor task during non-simultaneous fMRI and fNIRS acquisitions. First, fNIRS and fMRI data were integrated by projecting subject- and group-level source maps over the cortical surface mesh to define anatomically constrained functional ROIs (acfROI). Next, spatial agreement and temporal correlation were quantified as Dice Coefficient (DC) and Pearson's correlation coefficient between fNIRS-fMRI in the acfROIs.

RESULTS

Subject-level results revealed moderate to substantial spatial agreement (DC range 0.43 - 0.64), confirmed at the group-level only for blood oxygenation level-dependent (BOLD) signal vs. HbO2 (0.44 - 0.69), while lack of agreement was found for BOLD vs. HbR in some instances (0.05 - 0.49). Subject-level temporal correlation was moderate to strong (0.79 - 0.85 for BOLD vs. HbO2 and -0.62 to -0.72 for BOLD vs. HbR), while an overall strong correlation was found for group-level results (0.95 - 0.98 for BOLD vs. HbO2 and -0.91 to -0.94 for BOLD vs. HbR).

CONCLUSION

The proposed method directly compares fNIRS and fMRI by projecting individual source maps to the cortical surface. Our results indicate spatial and temporal correspondence between fNIRS and fMRI, and promotes the use of fNIRS when more ecological acquision settings are required, such as longitudinal monitoring of brain activity before and after rehabilitation.

Neural association between cognitive function and anhedonia in adolescents with melancholic major depressive disorder: A fNIRS study

BACKGROUND

Cognitive dysfunction is common among adolescent patients with major depressive disorder (MDD). However, the pattern and magnitude of cognition impairment in patients during melancholic episodes remains unclear. The purpose of this study was to compare the neurocognitive performance and the underlying cerebral blood flow activation of adolescent patients with melancholic and non-melancholic features.

METHODS

Fifty-seven and 44 adolescent patients with MDD with or without melancholic feature (MDD-MEL/nMEL) and 58 healthy controls (HCs) were recruited. We used the repeatable battery for the assessment of neuropsychological status (RBANS) measuring neurocognitive function, and used functional near infrared spectroscopy (fNIRS) monitoring cerebral hemodynamic changes, described by β value. The non-parametric test and post-hoc analysis were conducted in RBANS scores and β values among three groups. Spearman correlation and mediating analysis was performed for RBANS scores, β values, and clinical symptoms in the MDD-MEL group.

RESULTS

There were no significant difference in RBANS scores between MDD-MEL and MDD-nMEL group. Compared with patients in MDD-nMEL, patients in MDD-MEL have lower β values in eight channels (ch10, ch16, ch20, ch25, ch27, ch37, ch41, ch45). The cognitive function is significantly correlated with anhedonia, and the β values play a partial mediating role between anhedonia and cognitive function.

LIMITATION

It's a cross-sectional study and monitoring longitudinal effects are needed to further elucidate the mechanism.

CONCLUSION

The cognitive function in adolescents with MDD-MEL may not significantly differ from those with MDD-nMEL. However, the anhedonia may influenced the cognitive function by altering the function of medial frontal cortex.

Effects of age, gender, and education on task performance and prefrontal cortex processing during emotional and non-emotional verbal fluency tests

The emotional semantic fluency test (SFT) is an emerging verbal fluency test that requires controlled access to emotional lexical information. Currently, how demographic variables influence neurocognitive processing during this test remains elusive. The present study compared the effects of age, gender, and education on task performance and prefrontal cortex (PFC) processing during the non-emotional and emotional SFTs. One-hundred and thirty-three Cantonese-speaking adults aged 18-79 performed the non-emotional and emotional SFTs while their PFC activation was measured using functional near-infrared spectroscopy. Results showed that more education predicted better non-emotional SFT performance, whereas younger age, being female, and more education predicted better emotional SFT performance. Only age significantly affected PFC activation during the SFTs, and the effect was comparable between the two SFTs. Thus, compared with its non-emotional analog, the emotional SFT is influenced by overlapping yet distinct demographic variables. There is a similar age-related reorganization of PFC function across SFT performances.

Sound Level Changes the Auditory Cortical Activation Detected with Functional Near-Infrared Spectroscopy

BACKGROUND

Functional near-infrared spectroscopy (fNIRS) is a viable non-invasive technique for functional neuroimaging in the cochlear implant (CI) population; however, the effects of acoustic stimulus features on the fNIRS signal have not been thoroughly examined. This study examined the effect of stimulus level on fNIRS responses in adults with normal hearing or bilateral CIs. We hypothesized that fNIRS responses would correlate with both stimulus level and subjective loudness ratings, but that the correlation would be weaker with CIs due to the compression of acoustic input to electric output.

METHODS

Thirteen adults with bilateral CIs and 16 with normal hearing (NH) completed the study. Signal-correlated noise, a speech-shaped noise modulated by the temporal envelope of speech stimuli, was used to determine the effect of stimulus level in an unintelligible speech-like stimulus between the range of soft to loud speech. Cortical activity in the left hemisphere was recorded.

RESULTS

Results indicated a positive correlation of cortical activation in the left superior temporal gyrus with stimulus level in both NH and CI listeners with an additional correlation between cortical activity and perceived loudness for the CI group. The results are consistent with the literature and our hypothesis.

CONCLUSIONS

These results support the potential of fNIRS to examine auditory stimulus level effects at a group level and the importance of controlling for stimulus level and loudness in speech recognition studies. Further research is needed to better understand cortical activation patterns for speech recognition as a function of both stimulus presentation level and perceived loudness.

Use of functional near-infrared spectroscopy to quantify neurophysiological deficits after repetitive head impacts in adolescent athletes

There is concern that repetitive head impact exposure (RHIE) may lead to neurophysiological deficits in adolescents. Twelve high school varsity soccer players (5 female) completed the King-Devick (K-D) and complex tandem gait (CTG) assessments pre- and post-season while wearing a functional near-infrared spectroscopy (fNIRS) sensor. The average head impact load (AHIL) for each athlete-season was determined via a standardised protocol of video-verification of headband-based head impact sensor data. Linear mixed effect models were used to determine the effects of AHIL and task condition (3 K-D cards or 4 CTG conditions) on the change in mean prefrontal cortical activation measured by fNIRS, and performance on K-D and CTG, from pre- to post-season. Although there was no difference in the pre- to post-season change in K-D or CTG performance, greater AHIL was associated with greater cortical activation at post-season in comparison to pre-season during the most challenging conditions of K-D (p = 0.003) and CTG (p = 0.02), suggesting that greater RHIE necessitates increased cortical activation to complete the more challenging aspects of these assessments at the same level of performance. These results describe the effect of RHIE on neurofunction and suggest the need for further study of the time course of these effects.

Maintaining her image: A social comparative evaluation of the particularity of mothers in the Chinese cultural context

In Chinese culture, the mother holds a special meaning in one's self-concept, and is perceived as being stablyincorporated into and consistent with the self. However, it is unclear whether the evaluation of mothers by individuals is affected following the initiation of upward and downward social comparisons (USC and DSC). This experiment manipulated USC and DSC by evaluating positive and negative public figures and used functional near-infrared spectroscopy to record changes in brain activity during the evaluation. It was found that participants' evaluations of their mothers and their brain activity did not differ from the self during USC, verifying the equivalence of the mother and the self. In DSC, participants made significantly more positive social judgments about their mothers, accompanied by greater activation of the left temporal lobe. These results suggest that the mother was not only stably incorporated into the self but was in a position of even greater importance than the self. In DSC in particular, individuals are more likely to maintain a positive image of their mother.

Discovery and verification of bitter components in Panax notoginseng based on the integrated strategy of pharmacophore model, system separation and bitter tracing technology

Panax notoginseng is a world-renowned tonic herb, which has been used as a characteristic food in Southwest China for hundreds of years. However, the taste of Panax notoginseng is extremely bitter and serious after tasting, and its bitter components are unknown. This manuscript proposes a new strategy for discovering bitter components of Panax notoginseng based on the integrated analysis of pharmacophore model, system separation and bitter tracing technology. Firstly, 16 potential bitter components were obtained by UPLC-Q-Orbitrap HRMS combined with virtual screening, most of which were saponins.Then, the bitter components were further separated by system component separation and 5 potential bitter components were obtained. Finally, the main contributors of bitterness in Panax notoginseng were verified to be Ginsenoside Rg1, Ginsenoside Rb1 and Ginsenoside Rd by components knock-in and fNIRS. In general, this paper is the first literature report on the relatively systematic study of bitter components in Panax notoginseng.

Characteristics of corticomuscular coupling during wheelchair Tai Chi in patients with spinal cord injury

BACKGROUND

Wheelchair Tai Chi (WCTC) has been proved to have benefits for the brain and motor system of spinal cord injury (SCI) patients. However, the characteristics of corticomuscular coupling during WCTC are scarcely known. We aimed to investigate changes following SCI on corticomuscular coupling, and further compare the coupling characteristics of WCTC with aerobic exercise in SCI patients.

METHODS

A total of 15 SCI patients and 25 healthy controls were recruited. The patients had to perform aerobic exercise and WCTC, while healthy controls needed to complete a set of WCTC. The participants accomplished the test following the tutorial video in a sitting position. The upper limb muscle activation was measured from upper trapezius, medial deltoid, biceps brachii and triceps brachii with surface electromyography. Cortical activity in the prefrontal cortex, premotor cortex, supplementary motor area and primary motor cortex was simultaneously collected by functional near-infrared spectroscopy. The functional connectivity, phase synchronization index and coherence values were then calculated and statistically analyzed.

RESULTS

Compared to healthy controls, changes in functional connectivity and higher muscle activation were observed in the SCI group. There was no significant difference in phase synchronization between groups. Among patients, significantly higher coherence values between the left biceps brachii as well as the right triceps brachii and contralateral regions of interest were found during WCTC than during aerobic exercise.

CONCLUSION

The patients may compensate for the lack of corticomuscular coupling by enhancing muscle activation. This study demonstrated the potential and advantages of WCTC in eliciting corticomuscular coupling, which may optimize rehabilitation following SCI.

Classification of autism based on short-term spontaneous hemodynamic fluctuations using an adaptive graph neural network

BACKGROUND

Short-term spontaneous hemodynamic fluctuations were collected by the functional near-infrared spectroscopy (fNIRS) system to classify children with autism spectrum disorder (ASD) and typical development (TD), and to explore abnormalities in the left inferior frontal gyrus in ASD.

METHODS

Using the fNIRS data of 25 children with ASD and 22 children with TD, a graph neural network combined with the temporal convolution module and the graph convolution module was used, to extract the spatio-temporal features of the data and achieve accurate classification of ASD.

RESULTS

The graph neural network was used to obtain a good classification result in the left inferior frontal gyrus, with an accuracy of 97.1%, precision of 95.1%, and specificity of 93.4%. It was found that the 5th channel (which is located in BA 10) and the 8th channel (which is located in BA 47) in the left inferior frontal gyrus were closely correlated with ASD.

COMPARISON WITH PREVIOUSLY USED METHOD(S)

Compared with the previous deep learning model using the same input, the accuracy of our model has increased by up to 13%, and the correlation between channels in the left inferior frontal gyrus area with the best classification effect was explored through the graph neural network.

CONCLUSION

The adaptive graph neural network (AGNN) model may be able to mine more valuable information to distinguish ASD from TD and in addition, the left inferior frontal gyrus may have greater investigative value.

Identifying high cognitive load activities during simulated pediatric cardiac arrest using functional near-infrared spectroscopy

Aim

To identify specific activities associated with high cognitive load during simulated pediatric out-of-hospital cardiac arrest (POHCA) resuscitation using physiological monitoring with functional near-infrared spectroscopy (fNIRS).

Methods

We recruited teams of emergency medical services (EMS) responders from fire departments located throughout the Portland, OR metropolitan area to participate in POHCA simulations. Teams consisted of both paramedics and emergency medical technicians (EMTs), with one paramedic serving as the person in charge (PIC). The PIC was outfitted with the OctaMon to collect fNIRS signals from the prefrontal cortex. Signals reported changes in oxygenated and deoxygenated hemoglobin concentrations, which were used to determine moments of increased cognitive activity. Increased cognitive activity was determined by significant increases in oxygenated hemoglobin and decreases in deoxygenated hemoglobin. Significant changes in fNIRS signals were associated with specific concurrent clinical tasks recorded by two independent researchers using video review.

Results

We recorded cognitive activity of EMS providers in 18 POHCA simulations. We found that a proportion of PIC's experienced relatively high cognitive load during medication administration, defibrillation, and rhythm checks compared to other events.

Conclusion

EMS providers commonly experienced increased cognitive activity during key resuscitation tasks that were related to safely coordinating team members around calculating and administering medications, defibrillation, and rhythm and pulse checks. Understanding more about activities that require high cognitive demand can inform future interventions that reduce cognitive load.

Regulating effect of virtual reality restorative environment on prefrontal cortex dysfunction after night shifts in medical staff: an fNIRS study protocol for a randomized controlled trial in Dalian, China

BACKGROUND

Night shift work-related disturbed biological rhythm and insufficient sleep affect the functioning of brain activity and thus impair cognitive performance and mood state, which potentially leads to negative and even devastating results for both individuals and patients. A virtual reality (VR)-based restorative environment has shown to be an effective new technique to reduce stress and improve cognitive performance, but little is known about its mechanism of improving neuronal activity and connectivity.

METHODS

This is a randomized, controlled, single-center clinical trial. A total of 140 medical staff will be enrolled and randomized in a 1:1 allocation to either the VR immersion group (intervention group) or the control group. In the morning after the night shift, the participants in the intervention group will watch 360° panoramic videos of immersive VR natural restorative environments for 10 min, while the participants in the control group will just rest for 10 min. Assessments of abbreviated Profile of Mood States Questionnaire (POMS) and verbal fluency task (VFT) performances, as well as oxygenated hemoglobin (oxy-Hb) and deoxygenated hemoglobin (deoxy-Hb) and total hemoglobin concentration acquired by functional near-infrared spectroscopy (fNIRS) will be performed at baseline (day work), the morning after night shift but before the intervention (previous) and after intervention (post). Data collected after a night shift will be compared to baseline performance as well as between the two groups.

DISCUSSION

This trial will investigate the effects of the night shift and VR-based restorative environment intervention on mood, cognitive performance, and neuronal activity and connectivity. A positive result in this trial could encourage hospitals to apply VR technology to reduce physical and mental dysfunction during of night shifts among medical staff in every department. Furthermore, the findings from this study will contribute to understanding the underlying neuromodulation mechanisms of how restorative environments influence mood and cognition.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2200064769 . Registered on 17 October 2022.

Measuring cognitively demanding activities in pediatric out-of-hospital cardiac arrest

BACKGROUND

This methodological intersection article demonstrates a method to measure cognitive load in clinical simulations. Researchers have hypothesized that high levels of cognitive load reduce performance and increase errors. This phenomenon has been studied primarily by experimental designs that measure responses to predetermined stimuli and self-reports that reduce the experience to a summative value. Our goal was to develop a method to identify clinical activities with high cognitive burden using physiologic measures.

METHODS

Teams of emergency medical responders were recruited from local fire departments to participate in a scenario with a shockable pediatric out-of-hospital cardiac arrest (POHCA) patient. The scenario was standardized with the patient being resuscitated after receiving high-quality CPR and 3 defibrillations. Each team had a person in charge (PIC) who wore a functional near-infrared spectroscopy (fNIRS) device that recorded changes in oxygenated and deoxygenated hemoglobin concentration in their prefrontal cortex (PFC), which was interpreted as cognitive activity. We developed a data processing pipeline to remove nonneural noise (e.g., motion artifacts, heart rate, respiration, and blood pressure) and detect statistically significant changes in cognitive activity. Two researchers independently watched videos and coded clinical tasks corresponding to detected events. Disagreements were resolved through consensus, and results were validated by clinicians.

RESULTS

We conducted 18 simulations with 122 participants. Participants arrived in teams of 4 to 7 members, including one PIC. We recorded the PIC's fNIRS signals and identified 173 events associated with increased cognitive activity. [Defibrillation] (N = 34); [medication] dosing (N = 33); and [rhythm checks] (N = 28) coincided most frequently with detected elevations in cognitive activity. [Defibrillations] had affinity with the right PFC, while [medication] dosing and [rhythm checks] had affinity with the left PFC.

CONCLUSIONS

FNIRS is a promising tool for physiologically measuring cognitive load. We describe a novel approach to scan the signal for statistically significant events with no a priori assumptions of when they occur. The events corresponded to key resuscitation tasks and appeared to be specific to the type of task based on activated regions in the PFC. Identifying and understanding the clinical tasks that require high cognitive load can suggest targets for interventions to decrease cognitive load and errors in care.

Functional near-infrared spectroscopy in elderly patients with four types of dementia

BACKGROUND

Functional near-infrared spectroscopy (fNIRS) is commonly used to study human brain function by measuring the hemodynamic signals originating from cortical activation and provides a new noninvasive detection method for identifying dementia.

AIM

To investigate the fNIRS imaging technique and its clinical application in differential diagnosis of subtype dementias including frontotemporal lobe dementia, Lewy body dementia, Parkinson’s disease dementia (PDD) and Alzheimer’s disease (AD).

METHODS

Four patients with different types of dementia were examined with fNIRS during two tasks and a resting state. We adopted the verbal fluency task, working memory task and resting state task. Each patient was compared on the same task. We conducted and analyzed the fNIRS data using a general linear model and Pearson’s correlation analysis.

RESULTS

Compared with other types of dementias, fNIRS showed the left frontotemporal and prefrontal lobes to be poorly activated during the verbal fluency task in frontotemporal dementia. In Lewy body dementia, severe asymmetry of prefrontal lobes appeared during both verbal fluency and working memory tasks, and the patient had low functional connectivity during a resting state. In PDD, the patient’s prefrontal cortex showed lower excitability than the temporal lobe during the verbal fluency task, while the prefrontal cortex showed higher excitability during the working memory task. The patient with AD showed poor prefrontal and temporal activation during the working memory task, and more activation of frontopolar instead of the dorsolateral prefrontal cortex.

CONCLUSION

Different hemodynamic characteristics of four types of dementia (as seen by fNIRS imaging) provides evidence that fNIRS can serve as a potential tool for the diagnosis between dementia subtypes.

Neural Substrates for Hand and Shoulder Movement in Healthy Adults: A Functional near Infrared Spectroscopy Study

Characterization of cortical activation patterns during movements in healthy adults may help our understanding of how the injured brain works. Upper limb motor tasks are commonly used to assess impaired motor function and to predict recovery in individuals with neurological disorders such as stroke. This study aimed to explore cortical activation patterns associated with movements of the hand and shoulder using functional near-infrared spectroscopy (fNIRS) and to demonstrate the potential of this technology to distinguish cerebral activation between distal and proximal movements. Twenty healthy, right-handed participants were recruited. Two 10-s motor tasks (right-hand opening-closing and right shoulder abduction-adduction) were performed in a sitting position at a rate of 0.5 Hz in a block paradigm. We measured the variations in oxyhemoglobin (HbO₂) and deoxyhemoglobin (HbR) concentrations. fNIRS was performed with a 24-channel system (Brite 24®; Artinis) that covered most motor control brain regions bilaterally. Activation was mostly contralateral for both hand and shoulder movements. Activation was more lateral for hand movements and more medial for shoulder movements, as predicted by the classical homunculus representation. Both HbO₂ and HbR concentrations varied with the activity. Our results showed that fNIRS can distinguish patterns of cortical activity in upper limb movements under ecological conditions. These results suggest that fNIRS can be used to measure spontaneous motor recovery and rehabilitation-induced recovery after brain injury. The trial was restropectively registered on January 20, 2023: NCT05691777 (clinicaltrial.gov).

Machine Learning and Prediction in Fetal, Infant, and Toddler Neuroimaging: A Review and Primer

Predictive models in neuroimaging are increasingly designed with the intent to improve risk stratification and support interventional efforts in psychiatry. Many of these models have been developed in samples of children school-aged or older. Nevertheless, despite growing evidence that altered brain maturation during the fetal, infant, and toddler (FIT) period modulates risk for poor mental health outcomes in childhood, these models are rarely implemented in FIT samples. Applications of predictive modeling in children of these ages provide an opportunity to develop powerful tools for improved characterization of the neural mechanisms underlying development. To facilitate the broader use of predictive models in FIT neuroimaging, we present a brief primer and systematic review on the methods used in current predictive modeling FIT studies. Reflecting on current practices in more than 100 studies conducted over the past decade, we provide an overview of topics, modalities, and methods commonly used in the field and under-researched areas. We then outline ethical and future considerations for neuroimaging researchers interested in predicting health outcomes in early life, including researchers who may be relatively new to either advanced machine learning methods or using FIT data. Altogether, the last decade of FIT research in machine learning has provided a foundation for accelerating the prediction of early-life trajectories across the full spectrum of illness and health.

Context-specific effects of threatening faces on alerting, orienting, and executive control: A fNIRS study

Real-world threatening faces possess both useful and irrelevant attributes with respect to the current goal. How these attributes interact and affect attention, which comprises at least three processes hypothesized to engage the frontal lobes (alerting, orienting, and executive control), remains poorly understood. Here, the neurocognitive effects of threatening facial expressions on the three processes of attention were examined through the emotional Attention Network Test (ANT) and functional near-infrared spectroscopy (fNIRS). Forty-seven (20M, 27F) young adults performed a blocked version of the arrow flanker task with neutral and angry facial cues applied in three cue conditions (no, center, and spatial). Hemodynamic changes occurring in participants' frontal cortices during task performance were recorded by multichannel fNIRS. Behavioral results indicated that alerting, orienting, and executive control processes existed in both the neutral and angry conditions. However, depending on the context, angry facial cues affected these processes differently compared with neutral facial cues. Specifically, the angry face disrupted the classical decrease in reaction time from the no-cue to center-cue condition specifically during the congruent condition. Additionally, fNIRS results revealed significant frontal cortical activation during the incongruent vs. congruent task; neither cue nor emotion significantly affected frontal activation. Thus, the findings suggest that the angry face affects all three attentional processes while exerting context-specific effects on attention. They also imply that during the ANT, the frontal cortex is most involved in executive control. The present study offers essential insights into how various attributes of threatening faces interact and alter attention.

The Influence of Extrovert-Introvert Personality on Children's Cortical Activation with Attention Training Systems

Extrovert-Introvert personality can take an active role in affecting people's attitudes, tastes, and behaviors in education. However, little research has been conducted to study whether and how Extrovert-Introvert personality may influence children's interaction with the attention training system. In this manuscript, we present the results of a user study that not only measured the influence of children's Extrovert-Introvert personality on their perception of two typical types of attention training systems (i.e., computer-based and neurofeedback-based) but also employed functional near-infrared spectroscopy (fNIRS) to investigate how the personality may influence cortical activation in children. Our results show that, for extroverted children, the neurofeedback-based attention training system elicited significantly more activation in the prefrontal cortex and posterior parietal cortex, and was more likely to be preferred. The findings could be useful for developing more effective attention training systems based on user personality.

The relationship between the prefrontal cortex and limb motor function in stroke: A study based on resting-state functional near-infrared spectroscopy

BACKGROUND

With the ageing of the world population, the incidence of stroke has been increasing annually, becoming a public health problem affecting adult health. Limb motor dysfunction is one of the common complications of stroke and an important factor in disability. Therefore, restoring limb function is an important task in current rehabilitation. Accurate assessment of motor function in stroke patients is the basis for formulating effective rehabilitation strategies. With the development of neuroimaging technology, scholars have begun to study objective evaluation methods for limb motor dysfunction in stroke to determine reliable neural biomarkers to accurately identify brain functional activity and its relationship with limb motor function. The prefrontal cortex (PFC) plays an important role in motor control and in response to motor state changes. Our previous study found that the PFC network characteristics of stroke patients are related to their motor function status and the topological properties of the PFC network under resting state can predict the motor function of stroke patients to some extent. Therefore, this study used functional near-infrared spectroscopy (fNIRS) to evaluate prefrontal neuroplasticity markers and the relationships between such neural markers and limb motor function in stroke patients with limb motor dysfunction, which could be helpful to further clarify the relationship between brain neuroplasticity and cerebral haemodynamics. At the same time, through accurate and objective means of evaluation, it could be helpful for clinicians to formulate and optimize individualized rehabilitation treatment plans and accurately determine the rehabilitation efficacy and prognosis.

METHODS

This study recruited 17 S patients with limb motor dysfunction and 9 healthy subjects. fNIRS was used to collect 22 channels of cerebral blood oxygen signals in the PFC in the resting state. The differences in prefrontal oxygenated haemoglobin (HbO) and deoxygenated haemoglobin (HbR) concentrations were analysed between stroke patients and healthy subjects, and the lateralization index (LI) of HbO in stroke patients was also calculated. Pearson's correlation analysis was performed between the LI and the scores of the Fugl-Meyer Assessment Scale (FMA) of motor function in stroke patients.

RESULTS

The results found that the prefrontal HbO concentration was significantly decreased in stroke patients with limb motor dysfunction compared with healthy subjects, and there was a significant, positive correlation between the LI of the PFC and FMA scores in stroke patients.

CONCLUSION

These study results showed that stroke can cause cerebral haemodynamic changes in the PFC, and the functional imbalance of the left and right PFC in the resting state is correlated with the severity of limb motor dysfunction. Furthermore, we emphasize that the cerebral haemodynamic activity reflected by fNIRS could be used as a reliable neural biomarker for assessing limb motor dysfunction in stroke.

Transcranial direct current stimulation over the right dorsolateral prefrontal cortex increases oxyhemoglobin concentration and cognitive performance dependent on cognitive load

Transcranial direct current stimulation (tDCS) has been explored as a potential method for cognitive enhancement. tDCS may induce a cascade of neurophysiological changes including alterations in cerebral oxygenation. However, the effects of tDCS on the cognitive-cerebral oxygenation interaction remains unclear. Further, oxygenation variability across individuals remains minimally controlled for. The purpose of this sham-controlled study was to test the effects of anodal tDCS over the right dorsolateral prefrontal cortex (DLPFC) on the interaction between working memory and cerebral oxygenation while controlling for individual oxygenation variability. Thirty-three adults received resting-state functional near-infrared spectroscopy (fNIRS) recordings over bilateral prefrontal cortices. Following this, working memory was tested using a Toulouse n-back task concurrently paired with fNIRS, with measurements taken before and after 20 min of anodal or sham tDCS at 1.5 mA. With individual oxygenation controlled for, anodal tDCS was found to increase the oxyhemoglobin concentration over the right DLPFC during the 2-back (q = .015) and 3-back (q = .008) conditions. Additionally, anodal tDCS was found to improve accuracy during the 3-back task by 13.4 % (p = .028) and decrease latency by 250 ms (p = .013). The increase in oxyhemoglobin was strongly correlated with increases in accuracy (p = .041) and decreases in latency during the 3-back span (p = .017). Taken together, anodal tDCS over the right DLPFC was found to regionally increase oxyhemoglobin concentrations and improve working memory performance in higher cognitive load conditions.

Test-retest reliability of functional near-infrared spectroscopy during a finger-tapping and postural task in healthy older adults

Significance

Functional near-infrared spectroscopy (fNIRS) is increasingly employed in studies requiring repeated measurements, yet test-retest reliability is largely unknown.

Aim

To investigate test-retest reliability during a postural and a finger-tapping task with and without cap-removal.

Approach

Twenty healthy older adults performed a postural and a finger-tapping task. The tasks were repeated twice in one session and once the next day. A portable fNIRS system measured cortical hemodynamics (HbO2) in five regions of interest for the postural task and in the hand motor region for finger-tapping.

Results

Test-retest reliability without cap-removal was excellent for the prefrontal cortex (PFC), the premotor cortex (PMC) and the somatosensory cortex (SSC) (intraclass correlation coefficient (ICC)≥0.78), and fair for the frontal eye fields (FEF) and the supplementary motor area (SMA) (ICC≥0.48). After cap-removal, reliability reduced for PFC and SSC (ICC≥0.50), became poor for SMA (ICC=0.01) and PMC (ICC=0.00) and remained good for FEF (ICC=0.64). Similarly, good reliability (ICC=0.66) was apparent for the hand motor region without cap-removal, which deteriorated after cap-removal (ICC=0.38).

Conclusions

Test-retest reliability of fNIRS measurements during two separate motor tasks in healthy older adults was fair to excellent when the cap remained in place. However, removing the fNIRS cap between measurements compromised reliability.

Carbon dioxide protects simulated driving performance during severe hypoxia

PURPOSE

We sought to determine the effect of acute severe hypoxia, with and without concurrent manipulation of carbon dioxide (CO₂), on complex real-world psychomotor task performance.

METHODS

Twenty-one participants completed a 10-min simulated driving task while breathing room air (normoxia) or hypoxic air (P_ETO₂ = 45 mmHg) under poikilocapnic, isocapnic, and hypercapnic conditions (P_ETCO₂ = not manipulated, clamped at baseline, and clamped at baseline + 10 mmHg, respectively). Driving performance was assessed using a fixed-base motor vehicle simulator. Oxygenation in the frontal cortex was measured using functional near-infrared spectroscopy.

RESULTS

Speed limit exceedances were greater during the poikilocapnic than normoxic, hypercapnic, and isocapnic conditions (mean exceedances: 8, 4, 5, and 7, respectively; all p ≤ 0.05 vs poikilocapnic hypoxia). Vehicle speed was greater in the poikilocapnic than normoxic and hypercapnic conditions (mean difference: 0.35 km h^-1 and 0.67 km h^-1, respectively). All hypoxic conditions similarly decreased cerebral oxyhaemoglobin and increased deoxyhaemoglobin, compared to normoxic baseline, while total hemoglobin remained unchanged.

CONCLUSIONS

These findings demonstrate that supplemental CO₂ can confer a neuroprotective effect by offsetting impairments in complex psychomotor task performance evoked by severe poikilocapnic hypoxia; however, differences in performance are unlikely to be linked to measurable differences in cerebral oxygenation.

Differences in the prefrontal cortex responses of healthy young men performing either water-based or land-based exercise at light to moderate intensity

Cerebral blood flow increases more during water-based exercise than land-based exercise owing to the effects of end-tidal CO₂ (PETCO₂) and mean arterial pressure (MAP) changes due to water immersion. However, it is unclear whether oxygenated hemoglobin (oxy-Hb) concentrations in the prefrontal cortex (PFC) are increased more by water-based or land-based exercise. We hypothesized that oxy-Hb concentrations in the PFC are higher during water-based exercise than land-based exercise when the exercise intensity is matched. To test this hypothesis, 10 healthy participants (age: 24.2 ± 1.7 years; height: 1.75 ± 0.04 m; weight: 69.5 ± 5.2 kg) performed light- to moderate-intensity cycling exercise in water (water-based cycling (WC); chest-high water at 30 °C) and on land (LC). Stroke volume, cardio output, heart rate, MAP, respiratory rate, PETCO₂, and oxy-Hb in the PFC were assessed during 15 min of exercise, with exercise intensity increased every 5 min. Both WC and LC significantly increased oxy-Hb concentrations in the PFC as exercise intensity was increased (intensity effect: p < 0.001). There was no significant difference in oxy-Hb concentrations during WC and LC in most prefrontal areas, although significant differences were found in areas corresponding to the left dorsolateral PFC (exercise effect: p < 0.001). Thus, WC and LC increase oxy-Hb concentrations in the PFC in a similar manner with increasing exercise intensity, but part of the PFC exhibits enhanced oxy-Hb levels during WC. The neural response of the PFC may differ during water-based and land-based exercise owing to differences in external information associated with water immersion.

Controlling jaw-related motion artifacts in functional near-infrared spectroscopy

BACKGROUND

Functional near-infrared spectroscopy (fNIRS) as a non-invasive optical neuroimaging technique has demonstrated great potential in monitoring cerebral activity. Due to its portability and compatibility with medical implants, fNIRS has seen increasing applications in studying the hearing, language and cognitive functions. However, fNIRS is susceptible to artifacts related to jaw movements, such as teeth clenching, swallowing and speaking, which affect recordings over the temporal, parietal and frontal/prefrontal cortices.

NEW METHOD

We investigated two new approaches to control the jaw-related motion artifacts, an individually customized bite bar apparatus and a denoising algorithm namely PCA-GLM based on multi-channel fNIRS recordings from long-separation and short-separation montage. We first recorded data while subjects performed a clenching task, then an auditory task and a resting-state task with and without the bite bar.

RESULTS

Our results have shown that jaw clenching can introduce spurious, task-evoked-like responses in fNIRS signals. A bite bar customized for each participant effectively suppressed the movement-related activities in fNIRS, at both task and resting-state conditions. Moreover, the bite bar and the PCA-GLM denoising method are shown to improve auditory responses, by significantly reducing the within-subject standard deviation, increasing the task-related contrast-to-noise ratio, and yielding stronger activations to the auditory stimuli.

COMPARISON WITH EXISTING METHOD(S)

The current study has demonstrated a novel method to control the jaw-related motion artifacts in fNIRS signals.

CONCLUSIONS

Our method will benefit the study of the hearing, language and cognitive functions in normal healthy subjects and patients.

Different executive function impairments in medication-naïve children with attention-deficit/hyperactivity disorder comorbid with oppositional defiant disorder and conduct disorder

The impairment of executive functions (EFs) in attention-deficit/hyperactivity disorder (ADHD) might vary from one individual to another, indicating high heterogeneity. Comorbidity may contribute to this heterogeneity. Disruptive behavior disorders (DBD), including oppositional defiant disorder (ODD) and conduct disorder (CD), is the most common comorbidity in ADHD. Although many studies suggest that ADHD with CD (ADHD_CD+) and ADHD with ODD (ADHD_ODD+) should be treated differently, little research has attempted to separate these two disorders when studying the EFs and brain imaging of ADHD with DBD (ADHD_DBD+). Thus, based on our ongoing research in ADHD, we have now recruited a large sample size of medication-naïve children to obtain estimates of neurocognitive function and functional brain networks. We found no EF impairment in ADHD_CD+ patients compared with healthy controls (HCs). Correlation analysis showed that more severe CD symptoms were associated with better EFs. The mediation analysis revealed that the relationship between CD symptoms and inhibition function was mediated by the functional connectivity (FC) of SMN(L) - DMN(R) in the younger group. The study suggested that ADHD_CD+ and ADHD_ODD+ are different in their EF impairment. The comorbidity of CD may not worsen the impairments and might even improve EF performance within ADHD individuals.