Enhancing classification accuracy of HRF signals in fNIRS using semi-supervised learning and filtering.

This paper introduces a novel approach to enhance the classification accuracy of hemodynamic response function (HRF) signals acquired through functional near-infrared spectroscopy (fNIRS). Leveraging a semi-supervised learning (SSL) framework alongside a filtering technique, the study preprocesses HRF data effectively before applying the SSL algorithm. Collected from the prefrontal cortex, HRF signals capture variations in oxyhemoglobin (oxyHb) and deoxyhemoglobin (deoxyHb) levels in response to odor stimuli and air state. Training the classification model on a dataset containing filtered and feature-extracted HRF signals led to significant improvements in classification accuracy. By comparing the algorithm's performance before and after employing the proposed filtering technique, the study provides compelling evidence of its effectiveness. These findings hold promise for advancing functional brain imaging research and cognitive studies, facilitating a deeper understanding of brain responses across various experimental contexts.

Hemodynamics of the left cerebral hemisphere during silent reading:analysis using near-infrared spectroscopy.

The purpose of this study was to investigate the hemodynamic activity in the left cerebral hemisphere during silent reading in college students with typical development using near-infrared spectroscopy (NIRS). Sixty college students with typical development participated in this study. In the silent reading task, participants were asked to read a text from Andersen's fairy tale. Then, the change in oxygenated hemoglobin (oxy-Hb) concentration during silent reading of the text was calculated. The number of letters read during the silent reading task was also measured to calculate the silent reading speed. The average trend graph of 60 college students revealed increased oxy-Hb concentration in both the left inferior frontal gyrus (Broca's area) and the left inferior occipitotemporal gyrus during silent reading. A negative correlation was found between the change in oxy-Hb concentration in Broca's area and silent reading speed. A positive correlation was found between oxy-Hb concentration change in the left inferior occipitotemporal gyrus and silent reading speed. The increase in oxy-Hb concentration in Broca's area observed during silent reading may reflect effortful reading in students with reading difficulty. The increase in oxy-Hb concentration in the left inferior occipitotemporal gyrus observed during silent reading may reflect proficiency in reading. Our findings suggest the usefulness of NIRS in assessing reading function and its potential use in the diagnosis of developmental dyslexia. J. Med. Invest. 71 : 267-272, August, 2024.

Eumelanin and Pheomelanin Modelling in Optical Oximetry Using Pulse Oximetry (for 540 nm and 660 nm): DC Component.

Oximetry is used to quantify the presence of oxygen in soft tissues. It can be expressed as, for example, tissue oxygen saturation (StO2), arterial oxygen saturation (SaO2) and pulsatile oxygen saturation (SpO2), among others. Non-invasive medical devices are used to estimate (SaO2). Their accuracy is compromised in individuals with highly pigmented skin. The aim of this initial work is to go back few steps into the understanding of the light absorption for the DC component in pulse oximeters, by using a mixtures model for different hypothetical scenarios of normoxia and hyperoxia. Under hypoxic states, an initial and simple multi-wavelength approach could be established to identify the impact of eumelanin (EuM) and pheomelanin (PhM), which are directly related to skin pigmentation in dark skin colour individuals. We used public spectra for water (H2O), haemoglobin (HHb), oxy-haemoglobin (HbO2), eumelanin and pheomelanin, to create 1000 possible absorption combinations. These spectra simulations were used to understand the hypothetical limits, across a 450-800 nm wavelength range. These results have outlined the maximum oxy-haemoglobin concentrations that can be detected without interfering with eumelanin and pheomelanin. This initial and simple approach helped us to understand how eumelanin and pheomelanin absorption interferes and overlaps with low oxy-haemoglobin, which is a key biomarker for oxygen quantification in pulse oximeters and other non-invasive biomedical devices.

Regional Differences in Skeletal Muscle O2 Dynamics During Body-Weight Resistance Exercise with Slow Movement and Tonic Force Generation.

The aim of this study was to investigate the skeletal muscle O2 dynamics during body-weight resistance exercise with slow movement and tonic force generation. Thirteen untrained, healthy, young males performed Bulgarian split squats and push-ups until volitional failure. Relative changes from rest in oxygenated haemoglobin (oxy-Hb) and deoxygenated haemoglobin (deoxy-Hb) concentrations were continuously monitored at the vastus lateralis (VL) and rectus femoris (RF) muscles during squats, and pectoralis major (PM) and triceps brachii (TB) muscles during push-ups using spatial resolved near-infrared spectroscopy oximetry. During the squat exercise, deoxy-Hb continuously increased at RF until failure (10.8 ± 7.0 µmol/L), while at VL, deoxy-Hb was relatively maintained during 25-100% of the number of maximum repetitions (18.0 ± 7.4 µmol/L at volitional failure). During the push-up exercise, a significant increase in deoxy-Hb was observed during exercise from rest at PM and TB. We found a significant increase in oxy-Hb during exercise at PM (28.1 ± 15.8 µmol/L at volitional failure), while at TB, no significant difference was observed from rest (-2.7 ± 13.7 µmol/L at volitional failure). Our findings suggest that the deoxygenation patterns during body-weight squat exercise were heterogeneous within the quadriceps muscles. Moreover, differences in O2 dynamics between the trunk and extremity muscles may be partly explained by convective O2 supply during resistance exercise. However, future studies are needed due to inter-individual differences in skills for body-weight resistance exercise.

Relationship of Cognitive Function with Oxygenated Haemoglobin Concentration Difference Between the Left and Right Prefrontal Cortex During 40-Min Moderate-Intensity Exercise.

The high concentration of oxygenated haemoglobin (O2Hb) in the prefrontal cortex (PFC) during exercise improves cognitive performance. In this study, we aimed to elucidate the relationship of cognitive function with the O2Hb concentration difference between the left and right PFC (L-PFC and R-PFC, respectively) during sustained exercise. We enrolled 12 healthy adult males who, after a 4-min rest and warm-up, performed a 40-min exercise regime at a workload corresponding to 50% maximal oxygen consumption. A 2-back task was performed, and the reaction times (RTs) were recorded before exercise, immediately after exercise, and 20 min after exercise. Near-infrared spectroscopy was used to monitor L-PFC and R-PFC. RT was shortened immediately and 20 min after exercise, and O2Hb concentration difference between L-PFC and R-PFC positively correlated with RT 20 min after exercise. These findings suggest that 40-min exercise induced a phenomenon of neural compensation.

Differences in Brain Activity During Real and Virtual Reality Motor Tasks in Normal Healthy Individuals.

This study aimed to clarify the differences between brain activity during virtual reality and real motor tasks. Twelve healthy adults participated in this study. Near-infrared spectroscopy (NIRS) was used to measure brain activity, and a total of 34 channels, 17 channels each, centred on the bilateral motor cortex, were used as measurement sites. Two types of motor tasks were used: a real Box and Block test (R-BBT) and a virtual reality Box and Block test (VR-BBT). In both motor tasks, an increase in oxy-haemoglobin (O2Hb) and a slight decrease in deoxy-haemoglobin (HHb) levels were observed in the central region of the participant's motor cortex. The O2Hb in the motor cortex during R-BBT increased at the beginning of the task, rapidly decreased, and remained at a low value. Conversely, the amount of O2Hb in the motor cortex during the VR-BBT remained high throughout the task. In addition, O2Hb in the dorsal prefrontal cortex during the VR-BBT was significantly higher than during the R-BBT. This study indicates that brain activity differs significantly between real and virtual reality motor tasks, even for similar tasks.

Haemodynamic Responses to Spontaneous Neural Activity on the Electroencephalogram in Preterm Infants.

Delta brushes are spontaneous neural activities observed in preterm electroencephalograms (EEGs) and are thought to reflect the activities of subplate neurons in the developing brain. We investigated the haemodynamic responses associated with delta brushes in five preterm infants at two time points (at 33 or 34, and 36 weeks of postmenstrual age), using simultaneous EEG-functional near-infrared spectroscopy (NIRS). An automated detection algorithm was developed to identify the brush components of delta brushes in the bipolar EEG envelope; we placed eight EEG electrodes. An eight-channel NIRS device was placed around the head of each infant to measure changes in oxy- and deoxy-haemoglobin (Hb) concentrations. Haemodynamic grand averages were calculated for local brushes in each NIRS channel. We classified the responses into five patterns based on changes in oxy- and deoxy-Hb signals (positive in-phase/anti-phase, negative in-phase/anti-phase, and unclassified) and evaluated the relationship between the locations of NIRS measurements and those of brushes, as well as the haemodynamic response patterns and infant age at the time of recording. In all the 10 recordings, we found that positive responses (oxy-Hb increases) predominated, not only in the corresponding areas but also in remote areas. Particularly, notable responses were observed in the bilateral temporal areas. Among the positive responses, the proportion exhibiting an anti-phase pattern was 12% at 33 to 34 weeks of postmenstrual age and 54% at 36 weeks of postmenstrual age. Our unexpected finding of remarkable temporal responses to localised neuronal activity supports the hypothesis that the insula is the most strongly interconnected hub in the developing brain.

Effects of Head Elevation on Cerebral Oxygenation in Acute Cerebral Infarction.

This study clarifies the effects of head elevation on cerebral oxygenation in patients with acute cerebral infarction. We included 76 patients with anterior circulation cerebral infarction admitted to the stroke care unit within 7 days of symptom onset. Using near-infrared spectroscopy (NIRS), we measured regional saturation oxygen (rSO2), oxygenated haemoglobin (O2Hb), deoxygenated haemoglobin (HHb), and total haemoglobin (THb) in both the affected hemisphere (AH) and unaffected hemisphere (UH) after raising the head to 0°, 30°, and 60° for 1 minute each. The mean arterial pressure (MAP) was measured non-invasively at each position. Our result demonstrated a significant decrease in O2Hb as the head elevation angle (HEA) increased, with no observable interaction between the AH and UH. A significant decrease in rSO2 interaction was observed. In contrast, the HHb and THb levels changed significantly as the HEA increased, although no interactions were identified. No significant correlations existed between the observed changes in O2Hb, HHb, THb, or rSO2 and changes in MAP at each HEA.

Prefrontal Cortex Oxygenation During Walking in an Acute Ischaemic Stroke Patient with Severe Internal Carotid Artery Stenosis: A Case Report.

This study investigated the oxygenation in the prefrontal cortex (PFC) during walking in a 75-year-old male patient in the acute phase of a left frontal lobe cerebral infarction complicated by severe left internal carotid artery stenosis. The patient regained independent ambulation on the fifth day after the onset of symptoms, and the study was conducted on the eighth day after the onset of symptoms. The patient rested for 10 s before walking for 70 s. Then he rested for 60 s. The levels of oxyhaemoglobin (O2Hb), deoxyhaemoglobin (HHb), and total haemoglobin (THb) in the PFC were quantified during the rest and walking phases using a wearable near-infrared spectroscopy device. Comparative analysis with baseline values during rest revealed decreases in the O2Hb, HHb, and THb in both hemispheres of the PFC during walking (O2Hb: -19.76/ -14.88 µmol/L, HHb: -1.18/ -2.00 µmol/L, THb: -20.96/ -16.88 µmol/L, right/left, respectively). The recovery of the O2Hb was delayed by 15.8 seconds in the affected hemisphere. These findings support the effectiveness of wearable NIRS for the evaluation of cerebral oxygenation during rehabilitation in patients with acute stroke to facilitate evaluations and individualise patient care.

Changes in Cerebral Oxygenation in the Prefrontal Cortex During Cardiopulmonary Exercise Testing in Patients After Cardiovascular Surgery.

Oxygenated haemoglobin (O2Hb) and total haemoglobin (THb) concentrations rise with increasing exercise load during the cardiopulmonary exercise test (CPX); however, this elevated response is impaired in patients with chronic heart failure. Furthermore, the changes occurring in patients during the acute phase of cardiac surgery are unknown. This study aimed to measure cerebral oxygenation in the prefrontal cortex (PFC) during CPX in patients during the acute post-operative phase following cardiovascular surgery. Fourteen patients in the acute phase of post-cardiovascular surgery period were enrolled. CPX was administered between the post-operative period and discharge. The protocol employed the ramp method (10 W/min) after 3-min rest and 3-min warm-up periods. Levels of O2Hb, deoxygenated haemoglobin (HHb), THb, and the regional cerebral oxygen saturation (rSO2) in the PFC were measured from the resting state through the end of CPX using near-infrared spectroscopy. The mean values of O2Hb, HHb, and THb levels and rSO2 were compared at rest, warm-up, anaerobic threshold, and peak points. At the peak, O2Hb and rSO2 declined significantly, and HHb rose significantly compared to the respective values at rest; no significant changes were observed in THb. These findings suggest that the oxygen supply to the PFC is reduced in patients with reduced cardiac function following cardiovascular surgery.

Cortical activation during the verbal fluency task for obstructive sleep apnea patients with depressive symptoms: A multi-channel fNIRS study.

STUDY OBJECTIVE: The aim of our study was to elucidate differences in brain activity patterns among obstructive sleep apnea (OSA) patients, OSA patients with depressive symptoms, and healthy controls (HCs). We also investigated the relationship between brain function and depression in OSA patients. METHODS: A total of 95 subjects were included in the study, including 34 OSA patients without depressive symptoms, 31 OSA patients with depressive symptoms, and 30 HCs. The 53-channel functional near-infrared spectroscopy (fNIRS) was used to monitor the concentration of oxy-hemoglobin (Oxy-Hb) in the brain, whereas the participants performed the verbal fluency task, and the degree of depression was scored using the 17-item Hamilton Rating Scale for Depression (HAMD-17). Hierarchical regression models were conducted to analyze the association of fNIRS features with depressive symptom. RESULTS: The Oxy-Hb changes of the three groups were significantly different in Channels 25 (H = 9.878, p = .007) and 43 (H = 6.957, p = .031). Inter-group comparisons showed that the Oxy-Hb change of Channel 25 (located in the dorsolateral prefrontal cortex [DLPFC]) in OSA group was less than that in HC group (p = .006), and the Oxy-Hb change of Channel 43 (located in the right frontal polar region) in OSA group with depression was less than that in OSA group (p = .025). Spearman's test showed that there was a significant negative correlation between HAMD-17 scores and mean Oxy-Hb changes in Channel 43 (r = -.319, p < .05) in the OSA patients. Using hierarchical regression, Oxy-Hb changes in Channel 43 accounted for a significant proportion of the variation in outcome variables, even when accounting for other polysomnography features. CONCLUSIONS: Changes in the hemodynamic response of DLPFC may be a potential mechanism of executive dysfunction in OSA patients. And the right frontal polar region may be significant in assessing depressive symptoms in patients with OSA.

Noninvasive Assessing Low Back Pain by a Novel Near-Infrared Spectroscopy Flexible Probe With the Aid of Cupping Protocol.

Low back pain (LBP) is the leading cause of disability worldwide, yet its quantitative and noninvasive assessment remains challenging. Considering that near-infrared spectroscopy (NIRS) became a promising noninvasive tool for monitoring muscle and cupping therapy could regulate muscle blood flow to relieve LBP, we attempted to incorporate cupping and hemodynamics monitoring in muscle tissue by NIRS to assess LBP. We collected 3-min NIRS recordings on 12 LBP patients and 12 healthy subjects before and after 20-min cupping. Initially, no significant hemodynamic differences were observed between the groups. After cupping, the concentration changes of oxy-hemoglobin (Δ[HbO2]) in the emitter-detector channel parallel to spine unexpectedly exhibited that LBP was remarkably lower by approximately 67% compared with the controls. This study highlighted the potential of combining NIRS and cupping protocol as a quantitative assessment technique for LBP, also providing a new idea for clinical integration of novel optical assessment technologies.

Characteristic brain functional activation and connectivity during actual and imaginary right-handed grasp.

We used 34-channel functional near infrared spectroscopy to investigate and compare changes in oxyhemoglobin concentration of brain networks in bilateral prefrontal cortex, sensorimotor cortex, and occipital lobe of 22 right-handed healthy adults during executive right-handed grasp (motor execution task) and imagined right-handed grasp (motor imagery task). Then calculated lateral index and functional contribution degree, and measured functional connectivity strength between the regions of interest. In the motor executive block task, there was a significant increase in oxyhemoglobin concentration in regions of interest except for right occipital lobe (P<0.05), while in the motor imagery task, all left regions of interest's oxyhemoglobin concentration increased significantly (P<0.05). Except the prefrontal cortex in motor executive task, the left side of the brain was dominant. Left sensorimotor cortex played a major role in these two tasks, followed by right sensorimotor cortex. Among all functional contribution degree, left sensorimotor cortex, right sensorimotor cortex and left occipital lobe ranked top three during these tasks. In continuous acquisition tasks, functional connectivity on during motor imagery task was stronger than that during motor executive task. Brain functions during two tasks of right-hand grasping movement were partially consistent. However, the excitability of brain during motor imagery was lower, and it was more dependent on the participation of left prefrontal cortex, and its synchronous activity of the whole brain was stronger. The trend of functional contribution degree was basically consistent with oxyhemoglobin concentration and lateral index, and can be used as a novel index to evaluate brain function. [ChiCTR2200063792 (2022-09-16)].

Exploration of resting-state brain functional connectivity as preclinical markers for arousal prediction in prolonged disorders of consciousness: A pilot study based on functional near-infrared spectroscopy.

BACKGROUND: There is no diagnostic assessment procedure with moderate or strong evidence of use, and evidence for current means of treating prolonged disorders of consciousness (pDOC) is sparse. This may be related to the fact that the mechanisms of pDOC have not been studied deeply enough and are not clear enough. Therefore, the aim of this study was to explore the mechanism of pDOC using functional near-infrared spectroscopy (fNIRS) to provide a basis for the treatment of pDOC, as well as to explore preclinical markers for determining the arousal of pDOC patients. METHODS: Five minutes resting-state data were collected from 10 pDOC patients and 13healthy adults using fNIRS. Based on the concentrations of oxyhemoglobin (HbO) and deoxyhemoglobin (HbR) in the time series, the resting-state cortical brain functional connectivity strengths of the two groups were calculated, and the functional connectivity strengths of homologous and heterologous brain networks were compared at the sensorimotor network (SEN), dorsal attention network (DAN), ventral attention network (VAN), default mode network (DMN), frontoparietal network (FPN), and visual network (VIS) levels. Univariate binary logistic regression analyses were performed on brain networks with statistically significant differences to identify brain networks associated with arousal in pDOC patients. The receiver operating characteristic (ROC) curves were further analyzed to determine the cut-off value of the relevant brain networks to provide clinical biomarkers for the prediction of arousal in pDOC patients. RESULTS: The results showed that the functional connectivity strengths of oxyhemoglobin (HbO)-based SEN∼SEN, VIS∼VIS, DAN∼DAN, DMN∼DMN, SEN∼VIS, SEN∼FPN, SEN∼DAN, SEN∼DMN, VIS∼FPN, VIS∼DAN, VIS∼DMN, HbR-based SEN∼SEN, and SEN∼DAN were significantly reduced in the pDOC group and were factors that could reflect the participants' state of consciousness. The cut-off value of resting-state functional connectivity strength calculated by ROC curve analysis can be used as a potential preclinical marker for predicting the arousal state of subjects. CONCLUSION: Resting-state functional connectivity strength of cortical networks is significantly reduced in pDOC patients. The cut-off values of resting-state functional connectivity strength are potential preclinical markers for predicting arousal in pDOC patients.

Comparative analysis of the effects of the computer-based and paper-based trail making tests on oxygenation in the prefrontal cortex.

The trail making test (TMT) is a commonly used tool for evaluating executive functions, and the activation of cerebral oxygenation in the prefrontal cortex (PFC) during the test can reflect the participation of executive function. This study aimed to compare the differences in cerebral oxygenation in the PFC between the computer- and paper-based versions of the TMT and provide a theoretical basis for the optimization and clinical application of the computer-based version. A total of 32 healthy adult participants completed the computer- and paper-based TMT Types A and B. Cerebral oxygenation changes in the PFC were monitored during the experiment using near-infrared spectroscopy. Moreover, average changes in oxyhemoglobin (Δoxy-Hb) levels at the baseline and during activation periods in different types of testing were compared and analyzed. The number of correct connections in the computer-based version Type B was less than that in the paper-based version Type B (p < .001). The task time of the computer-based version was longer than that of the paper-based version (p < .001). The B/A ratio of the number of correct connections in the computer-based version was lower than that in the paper-based version (p < .001). The Δoxy-Hb in the PFC of the paper-based version was higher than that of the computer-based version (p < .001). Significant differences in oxygenation in the PFC were observed between the paper- and computer-based versions of TMT. After further improvement and correction in the subsequent development of the computer-based TMT, and taking into account the psychological feelings and preferences of the participants when performing different versions of the TMTs, the computer-based TMT is expected to play a good auxiliary role in clinical evaluation.

Effects of an online mindfulness-based intervention on brain haemodynamics: a pilot randomized controlled trial using functional near-infrared spectroscopy.

Although many neuroimaging studies have evaluated changes in the prefrontal cortex during mindfulness-based interventions, most of these studies were cross-sectional studies of skilled participants or involved pre-post comparisons before and after a single session. While functional near-infrared spectroscopy is a useful tool to capture changes in the hemodynamic response of the prefrontal cortex during continuous mindfulness-based intervention, its ability to detect the accumulated effects of continuous mindfulness-based intervention is currently unclear. We investigated whether a 12-wk online mindfulness-based intervention changed the hemodynamic response of the prefrontal cortex during a verbal fluency task. Eighty-two healthy university students were randomly allocated to a 12-wk online mindfulness-based intervention group or a wait-list control group. The integral values of oxygenated hemoglobin measured using functional near-infrared spectroscopy before and after the intervention were compared to the values in the wait-list group. The intervention condition showed significantly greater functional near-infrared spectroscopy signal activation than the control condition; however, the effect sizes before and after the intervention were small. Thus, continuous mindfulness-based intervention could alter prefrontal cortex function, and functional near-infrared spectroscopy could be useful for measuring the accumulated effects of continuous mindfulness-based interventions. With a better understanding of the association between mindfulness and functional near-infrared spectroscopy signals, functional near-infrared spectroscopy can be used for biofeedback analyses.

Sleep-related bruxism, microarousals and oxyhaemoglobin desaturations in sleep stages: A cross-sectional study in a large apnoeic population.

BACKGROUND: Sleep-related bruxism (SB) is the habit of grinding or clenching the teeth during sleep, mediated by the non-peripheral central nervous system. PURPOSE: The objectives of this cross-sectional study were to evaluate associations between SB, microarousals and oxyhaemoglobin desaturations and to compare the frequency of SB and microarousals in sleep stages, in an apnoeic population. METHODS: Two hundred and forty individuals composed the sample, who underwent a single full-night polysomnography. Self-reports and clinical inspections were not considered for assessing SB. The polysomnographic assessment of SB was performed using electrodes placed on masseter muscles and chin. SB was defined as more than two events of rhythmic masticatory muscle activity per hour of sleep. Microarousals were considered when there were abrupt changes in electroencephalogram frequencies, without complete awakening, lasting from 3 to 15 s. Oxyhaemoglobin desaturations were defined as significant drops (≥3%) in basal oxygen saturations. With these data, SB, microarousals and oxyhaemoglobin desaturations were evaluated and submitted to statistical analysis. RESULTS: Statistically significant differences were observed between bruxers and non-bruxers when comparing the rates of microarousals (p < .001) and oxyhaemoglobin desaturations (p = .038). There was a higher number of SB and microarousals in NREM (non-rapid eye movement) two sleep stage (p < 0.001). Bruxers had a greater risk of higher numbers of microarousals (OR = 1.023; p = .003), which did not occur for oxyhaemoglobin desaturations (OR = 0.998; p = .741). CONCLUSIONS: A higher number of microarousals presents relationship with SB; associations between SB and oxyhaemoglobin desaturations remained inconclusive; higher frequency of SB and microarousals was observed in NREM 2 sleep stage.

Two Independent Response Mechanisms to Auditory Stimuli Measured with Functional Near-Infrared Spectroscopy in Sleeping Infants.

This study investigated the morphology of the functional near-infrared spectroscopy (fNIRS) response to speech sounds measured from 16 sleeping infants and how it changes with repeated stimulus presentation. We observed a positive peak followed by a wide negative trough, with the latter being most evident in early epochs. We argue that the overall response morphology captures the effects of two simultaneous, but independent, response mechanisms that are both activated at the stimulus onset: one being the obligatory response to a sound stimulus by the auditory system, and the other being a neural suppression effect induced by the arousal system. Because the two effects behave differently with repeated epochs, it is possible to mathematically separate them and use fNIRS to study factors that affect the development and activation of the arousal system in infants. The results also imply that standard fNIRS analysis techniques need to be adjusted to take into account the possibilities of multiple simultaneous brain systems being activated and that the response to a stimulus is not necessarily stationary.

Hemodynamics of short-duration light-intensity physical exercise in the prefrontal cortex of children: a functional near-infrared spectroscopy study.

Identifying the types of exercise that enhance cerebral blood flow is crucial for developing exercise programs that enhance cognitive function. Nevertheless, few studies have explored the amount of light-intensity, short-duration exercises that individuals can easily perform on cerebral blood flow, particularly in children. We examined the effects of these exercises on the hemodynamics of the prefrontal cortex (PFC) using functional near-infrared spectroscopy. Participants comprised 41 children (aged 12.1 ± 1.5 years, 37% female) who engaged in seven light-intensity exercises, with each movement performed in two patterns lasting 10 or 20 s. Changes in oxygenated hemoglobin (oxy-Hb) levels at rest and during exercise were compared using analysis of covariance, with sex and age as covariates. Significant increases in oxy-Hb were observed in multiple regions of the PFC during all forms of exercise (including dynamic and twist stretching [66.6%, 8/12 regions, η2 = 0.07-0.27], hand and finger movements [75.0%, 9/12 regions, η2 = 0.07-0.16], and balance exercises (100.0%, 6/6 regions, η2 = 0.13-0.25]), except for static stretching with monotonic movements. This study implies that short-duration, light-intensity exercises, provided that they entail a certain degree of cognitive and/or physical demands, can activate the PFC and increase blood flow.

Adaptive Changes in Neurovascular Properties With Binocular Accommodation Functions in Myopic Participants by 3D Visual Training: An EEG and fNIRS Study.

Although three-dimensional visual training (3DVT) has been used for myopia intervention, its neural mechanisms remain largely unknown. In this study, visual function was examined before and after 3DVT, while resting-state EEG-fNIRS signals were recorded from 38 myopic participants. A graph theoretical analysis was applied to compute the neurovascular properties, including static brain networks (SBNs), dynamic brain networks (DBNs), and dynamic neurovascular coupling (DNC). Correlations between the changes in neurovascular properties and the changes in visual functions were calculated. After 3DVT, the local efficiency and node efficiency in the frontal lobes increased in the SBNs constructed from EEG δ -band; the global efficiency and node efficiency in the frontal-parietal lobes decreased in the DBNs variability constructed from EEG δ -band. For the DNC constructed with EEG α -band and oxyhemoglobin (HbO), the local efficiency decreased, for EEG α -band and deoxyhemoglobin (HbR), the node efficiency in the frontal-occipital lobes decreased. For the SBNs constructed from HbO, the functional connectivity (FC) between the frontal-occipital lobes increased. The DNC constructed between the FC of the frontal-parietal lobes from EEG ß -band and the FC of the frontal-occipital lobes from HbO increased, and between the FC of the frontal-occipital lobes from EEG ß -band and the FC of the inter-frontal lobes from HbR increased. The neurovascular properties were significantly correlated with the amplitude of accommodation and accommodative facility. The result indicated the positive effects of 3DVT on myopic participants, including improved efficiency of brain networks, increased FC of SBNs and DNC, and enhanced binocular accommodation functions.