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Group-level t-score maps in FC between the right PFC and all other cortical regions compared between tPBM and placebo conditions at A) stimulation, and B) post-stimulation periods. Red lines indicate higher FC during tPBM than the placebo stimulations and blue lines indicate the opposite. Only significant (p < 0.05, FDR corrected) FC changes are shown. Black boxes enclose channels within the right PFC; Red circle marks the approximate location of tPBM. Different ROIs are denoted by color: frontopolar (FP) (red), dorsolateral prefrontal cortex (DLPFC) (yellow), Broca’s area (green), premotor cortex (PMC) (light blue), primary motor and somatosensory cortical (M1/S1) areas (dark blue), somatosensory association cortex (SAC) (pink), and Wernicke’s Area (gold).
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Transcranial photobiomodulation (tPBM) with near-infrared light on the human head has been shown to enhance human cognition. In this study, tPBM-induced effects on resting state brain networks were investigated using 111-channel functional near-infrared spectroscopy over the whole head. Measurements were collected with and without 8-minute tPBM in...
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Methods
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Objective:
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Citations
... However, it is not clear whether both wavelength ranges result in similar physiological effects or whether one is better than the other 76 . A sizable number of studies have reported the physiological effects of a 1064-nm laser 10,27,29,31,33,36,37,39,52,[77][78][79] . In this study, we explored the physiological effects of 800-nm tPBM, which would guide the optimal selection of wavelengths for more effective outcomes of tPBM. ...
Cerebral infra-slow oscillation (ISO) is a source of vasomotion in endogenic (E; 0.005–0.02 Hz), neurogenic (N; 0.02–0.04 Hz), and myogenic (M; 0.04–0.2 Hz) frequency bands. In this study, we quantified changes in prefrontal concentrations of oxygenated hemoglobin (Δ[HbO]) and redox-state cytochrome c oxidase (Δ[CCO]) as hemodynamic and metabolic activity metrics, and electroencephalogram (EEG) powers as electrophysiological activity, using concurrent measurements of 2-channel broadband near-infrared spectroscopy and EEG on the forehead of 22 healthy participants at rest. After preprocessing, the multi-modality signals were analyzed using generalized partial directed coherence to construct unilateral neurophysiological networks among the three neurophysiological metrics (with simplified symbols of HbO, CCO, and EEG) in each E/N/M frequency band. The links in these networks represent neurovascular, neurometabolic, and metabolicvascular coupling (NVC, NMC, and MVC). The results illustrate that the demand for oxygen by neuronal activity and metabolism (EEG and CCO) drives the hemodynamic supply (HbO) in all E/N/M bands in the resting prefrontal cortex. Furthermore, to investigate the effect of transcranial photobiomodulation (tPBM), we performed a sham-controlled study by delivering an 800-nm laser beam to the left and right prefrontal cortex of the same participants. After performing the same data processing and statistical analysis, we obtained novel and important findings: tPBM delivered on either side of the prefrontal cortex triggered the alteration or reversal of directed network couplings among the three neurophysiological entities (i.e., HbO, CCO, and EEG frequency-specific powers) in the physiological network in the E and N bands, demonstrating that during the post-tPBM period, both metabolism and hemodynamic supply drive electrophysiological activity in directed network coupling of the prefrontal cortex (PFC). Overall, this study revealed that tPBM facilitates significant modulation of the directionality of neurophysiological networks in electrophysiological, metabolic, and hemodynamic activities.
... In addition, it is important to consider the potential differences in t-PBM treatment effects between developing brains in children and fully developed adult brains. While t-PBM might impact brain connectivity differently in these two groups (Urquhart et al., 2020), studies focusing on t-PBM applied for other neuropsychiatric disorders with children are scarce (Hamilton et al., 2022;Leisman et al., 2018;Pallanti et al., 2022). Therefore, clinical trials should stratify participants by age to discern any agedependent variations in t-PBM's effectiveness. ...
Obsessive-compulsive disorder (OCD) is a disabling neuropsychiatric disorder that affects about 2%-3% of the global population. Despite the availability of several treatments , many patients with OCD do not respond adequately, highlighting the need for new therapeutic approaches. Recent studies have associated various inflammatory processes with the pathogenesis of OCD, including alterations in peripheral immune cells, alterations in cytokine levels, and neuroinflammation. These findings suggest that inflammation could be a promising target for intervention. Transcranial photobio-modulation (t-PBM) with near-infrared light is a noninvasive neuromodulation technique that has shown potential for several neuropsychiatric disorders. However, its efficacy in OCD remains to be fully explored. This study aimed to review the literature on inflammation in OCD, detailing associations with T-cell populations, monocytes, NLRP3 inflammasome components, microglial activation, and elevated proinflamma-tory cytokines such as TNF-α, CRP, IL-1β, and IL-6. We also examined the hypothesis-based potential of t-PBM in targeting these inflammatory pathways of OCD, focusing on mechanisms such as modulation of oxidative stress, regulation of immune cell function, reduction of proinflammatory cytokine levels, deactivation of neurotoxic microglia, and upregulation of BDNF gene expression. Our review suggests that t-PBM could be a promising, noninvasive intervention for OCD, with the potential to modulate underlying inflammatory processes. Future research should focus on rand-omized clinical trials to assess t-PBM's efficacy and optimal treatment parameters in OCD. Biomarker analyses and neuroimaging studies will be important in understanding the relationship between inflammatory modulation and OCD symptom improvement following t-PBM sessions.
... In additional to facilitating lymphatic drainage, the release of NO during tPBM could also increase cerebral blood flow 192 and might contribute to the enhancement of cerebral endogenic and myogenic functional connectivity (FC). 171,[193][194][195] Except for tPBM-mediated NO regulation, it has been demonstrated that tPBM can attenuate cerebral Aβ burden through the activation of the cAMP-dependent protein kinase signaling pathway, mediated by CCO, as well as via the stimulation of microglia and angiogenesis. 75,80,196 In addition, Tao et al. reported that PBM (1070 nm) reduces the Aβ levels in the brain via stimulating and recruiting microglia to the Aβ burden 75 (Fig. 5) and increasing cerebral vessel density. ...
The brain diseases account for 30% of all known diseases. Pharmacological treatment is hampered by the blood–brain barrier, limiting drug delivery to the central nervous system (CNS). Transcranial photobiomodulation (tPBM) is a promising technology for treating brain diseases, due to its effectiveness, non-invasiveness, and affordability. tPBM has been widely used in pre-clinical experiments and clinical trials for treating brain diseases, such as stroke and Alzheimer’s disease. This review provides a comprehensive overview of tPBM. We summarize emerging trends and new discoveries in tPBM based on over one hundred references published in the past 20 years. We discuss the advantages and disadvantages of tPBM and highlight successful experimental and clinical protocols for treating various brain diseases. A better understanding of tPBM mechanisms, the development of guidelines for clinical practice, and the study of dose-dependent and personal effects hold great promise for progress in treating brain diseases.
... However, it is not clear whether both wavelength ranges result in similar physiological effects or whether one is better than the other 71 . A sizable number of studies have reported the physiological effects of a 1064-nm laser 10,26,28,30,32,[35][36][37]47,[72][73][74] . In this study, we explored the physiological effects of 800-nm tPBM, which would guide the optimal selection of wavelengths for more effective outcomes of tPBM. ...
Cerebral infra-slow oscillation (ISO) is a source of vasomotion in endogenic (E; 0.005–0.02 Hz), neurogenic (N; 0.02–0.04 Hz), and myogenic (M; 0.04–0.2 Hz) frequency bands. In this study, we quantified changes in prefrontal concentrations of oxygenated hemoglobin (Δ[HbO]) and redox-state cytochrome c oxidase (Δ[CCO]) as hemodynamic and metabolic activity metrics, and electroencephalogram (EEG) powers as electrophysiological activity, using concurrent measurements of 2-channel broadband near-infrared spectroscopy and EEG on the forehead of 22 healthy participants at rest. After preprocessing, the multi-modality signals were analyzed using generalized partial directed coherence to construct unilateral neurophysiological networks among the three neurophysiological metrics (with simplified symbols of HbO, CCO, and EEG) in each E/N/M frequency band. The links in these networks represent neurovascular, neurometabolic, and metabolicvascular coupling (NVC, NMC, and MVC). The results illustrate that the demand for oxygen by neuronal activity and metabolism (EEG and CCO) drives the hemodynamic supply (HbO) in all E/N/M bands in the resting prefrontal cortex. Furthermore, to investigate the effect of transcranial photobiomodulation (tPBM), we performed a sham-controlled study by delivering an 800-nm laser beam to the left and right prefrontal cortex of the same participants. After performing the same data processing and statistical analysis, we obtained novel and important findings: tPBM delivered on either side of the prefrontal cortex triggered the alteration or reversal of directed network couplings among the three neurophysiological entities (i.e., HbO, CCO, and EEG frequency-specific powers) in the physiological network in the E and N bands, demonstrating that during the post-tPBM period, both metabolism and hemodynamic supply drive electrophysiological activity in directed network coupling of the PFC. Overall, this study revealed that tPBM facilitates significant modulation of the directionality of neurophysiological networks in electrophysiological, metabolic, and hemodynamic activities.
... PBM has also be used to counter nerve damage in the sinuses, the cranial nerves (including the olfactory and gustatory sensory nerves), and the brain by repairing sensory receptors (ion channels) or by replacing damaged neurons altogether through apoptosis and neurogenesis. The improvement of long COVID symptoms of brain fog, depression, and mental health deficits through transcranial PBM has also been attributed to improved circulation and neural connectivity 222 . ...
Background. Infectivity, genomic variability, and symptomatic diversity of the SARS-CoV-2 virus represents a persistent challenge in the treatment of acute and long COVID-19 diseases. A direct consequence of pervasive ACE-2 receptors susceptible to the virion’s spike protein, disease trajectories commence as upper respiratory infection migrating into bronchia (presenting coughing, dyspnea, and fever), followed by viremic infection and circulatory distress from inflammation of visceral epithelium and vascular endothelia, decreased blood perfusion, and hypoxia. Severe cases include hyperinflammation, cytokine storms, and multisystem inflammatory syndrome with lung and nerve damage, and chronic cognitive deficits. Method. This paper (Part I) considers the requirements for treating acute and chronic COVID-19 with deep-tissue photobiomodulation (PBM) of sinuses, lungs and other ACE-2 populated organs using transdermal and transcranial light as a primary therapeutic modality. Analysis. A detailed analysis of optics, biophysics, numerical simulations, and quantum photochemistry for non-invasive deep tissue PBM of SARS-CoV-2 infected organs was performed including optical design, photonic control, irradiance, fluence, modulation, and protocols. Results. Analysis concludes large-area 3D bendable LED pads are best suited for deep-tissue PBM to transdermally treat whole-organ infection of the lungs, sinuses, abdominal cavity (and to transcranially treat long-COVID). Robotic laser scanning represents another viable option for deep-tissue PBM provided the optical angle of incidence is minimal. Penetration depth depends on wavelength (not optical power) with red (635nm) and NIR (850nm) shown to adequately penetrate through cutaneious tissue and parietal fascia into viscera. Conclusions. Red and NIR LEDs with average pulsed irradiances of 8.5 and 13.5 mW/cm2 respectively deliver hands-free whole-organ deep-tissue doses of between 0.5 to 4.0 J/cm2 in 60 min sessions from a surface dose of Pl/A = 40 J/cm2 depending on tissue transmission coefficients Yx at depth x>6mm. The designed photonic PBM system performs algorithmic variable frequency pulsed protocols covering up to 1,200 cm2. Duty factor control limits skin temperatures below 43°C irrespective of pulse modulating frequency. A mechanistic model for deep-tissue PBM, phenomenologically consistent with biophysics, photon penetration studies, COVID disease trajectories, and patient recovery profiles is presented. Part II details various acute and chronic case studies and positive outcomes thereof confirming PBM as a efficacious modality for COVID-19.
... Intriguingly, recent studies have also found that the promising effect of tPBM on brain function is still observed in the large-scale functional connectivity network [56], [57]. For instance, in a study employing functional magnetic resonance imaging (fMRI), Dmochowski et al. stimulated the right frontal lobe with tPBM and observed brain-wide functional connectivity (FC) increases during the stimulation, with a quarter of all connections showing such a significant increase [56]. ...
... For instance, in a study employing functional magnetic resonance imaging (fMRI), Dmochowski et al. stimulated the right frontal lobe with tPBM and observed brain-wide functional connectivity (FC) increases during the stimulation, with a quarter of all connections showing such a significant increase [56]. Consistently, an fNIRS study evaluated the cerebral changes across the whole brain brought by tPBM to the right forehead and discovered increases in the global small-world efficiency [57]. Similar results were found in studies adopting other neuromodulation techniques. ...
Transcranial photobiomodulation (tPBM) is an emerging non-invasive light-based neuromodulation technique that shows promising potential for improving working memory (WM) performance in older adults. However, the neurophysiological mechanisms associated with tPBM that underlie the improvement of WM and the persistence of such improvement have not been investigated. Sixty-one healthy older adults were recruited to receive a baseline sham stimulation, followed by one-week active tPBM (12 min daily, 1064-nm laser, 250 mW/cm
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) and three-week follow-ups. N-back WM task was conducted on post-stimulation of the baseline, the first (Day 1) and seventh (Day 7) days of the active treatment, and at the follow-ups. During the task, functional near-infrared spectroscopy (fNIRS) imaging was employed to record the cortical hemodynamic changes. Brain activations during the active and follow-up sessions were compared with the baseline to determine how tPBM had changed cortical hemodynamic activity and how long these changes persisted. We found that tPBM stimulation on Day 1 induced significantly decreased activation in the right hemisphere during the 3-back. The decreased activation expanded from only the right hemisphere on Day 1 to both hemispheres on Day 7. The decreased activation persisted for one week in the right supramarginal gyrus and the left angular gyrus and two weeks in the left somatosensory association cortex. These activation changes were accompanied by significantly improved task accuracy during the N-back. These findings provide important evidence for understanding neural mechanisms underlying cognitive enhancement after tPBM.
... Functional and broadband NIRS use the optical properties of oxyhaemoglobin (HbO) and desoxyhaemoglobin (desoxyHb) to evaluate brain activity, before, during and after tPBM stimulation. Eight studies have used this method, mainly at rest (Pruitt et al. 2020;Saucedo et al. 2021;Tian et al. 2016;Urquhart et al. 2020;Wang et al. 2017;Wang et al. 2022a;Wu et al. 2020). Typically, these studies used a broadband NIRS to investigate the metabolic (Δ[oxy-CCO]) and haemodynamic (Δ[HbO] and Δ[desoxyHb]) effects of a single session of 8-10 min laser stimulation at 1064 nm directed on the forehead, in comparison with sham. ...
... Finally, a fNIRS study recorded haemodynamic parameters in twelve regions of interests using a 111-channel NIRS device located over the whole brain (Urquhart et al. 2020). In this study, correlation analyses were done to evaluate the functional connectivity between the twelve areas of the brain. ...
... When examining at the global level, an increased global complexity and efficiency of the networks has been found (Urquart et al. 2020), which seemed frequency dependent (Gadheri et al. 2021;Shahdadian et al. 2022;Zomorrodi et al. 2019). Changes at the local level indicated improvement of segregation capacities, presumably resulting in better integration and information processing locally (Gadheri et al. 2021;Shahdadian et al. 2022;Urquhart et al. 2020). Taken together, these results indicated a modification of the topology of brain networks by tPBM, probably by modulating inhibitory and excitatory loops at the large-scale level, but more research is clearly needed to understand the precise nature of these changes and their consequences. ...
In recent years, transcranial photobiomodulation (tPBM) has been developing as a promising method to protect and repair brain tissues against damages. The aim of our systematic review is to examine the results available in the literature concerning the efficacy of tPBM in changing brain activity in humans, either in healthy individuals, or in patients with neurological diseases. Four databases were screened for references containing terms encompassing photobiomodulation, brain activity, brain imaging, and human. We also analysed the quality of the included studies using validated tools. Results in healthy subjects showed that even after a single session, tPBM can be effective in influencing brain activity. In particular, the different transcranial approaches - using a focal stimulation or helmet for global brain stimulation - seemed to act at both the vascular level by increasing regional cerebral blood flow (rCBF) and at the neural level by changing the activity of the neurons. In addition, studies also showed that even a focal stimulation was sufficient to induce a global change in functional connectivity across brain networks. Results in patients with neurological disease were sparser; nevertheless, they indicated that tPBM could improve rCBF and functional connectivity in several regions. Our systematic review also highlighted the heterogeneity in the methods and results generated, together with the need for more randomised controlled trials in patients with neurological diseases. In summary, tPBM could be a promising method to act on brain function, but more consistency is needed in order appreciate fully the underlying mechanisms and the precise outcomes.
... It has been suggested that tPBM up-regulates complex IV of the mitochondrial respiratory chain to modulate cytochrome c oxidase (CCO). This leads to increased adenosine triphosphate (ATP) formation and initiates secondary cell signaling pathways (5)(6)(7). The resulting metabolic effects following PBM increase cerebral metabolic energy production, oxygen consumption, and blood flow in animals and humans (8)(9)(10)(11). ...
... lateral visual network). Another independent set of studies from the same group revealed that 1064-nm tPBM on the right PFC increased hemodynamic activities across the entire cortical region and enhanced topographical functional connectivity between the right PFC stimulation site and parietal regions (5,39). Together, these studies show that 1064-nm tPBM on the right PFC of the resting human brain modulates both regional-specific activity and functional connectivity as observed in EEG and hemodynamic data. ...
Transcranial photobiomodulation (tPBM) is a safe and noninvasive intervention that has shown promise for improving cognitive performance. Whether tPBM can modulate brain activity and thereby enhance working memory (WM) capacity in humans remains unclear. In this study, we found that 1064-nm tPBM applied to the right prefrontal cortex (PFC) improves visual working memory capacity and increases occipitoparietal contralateral delay activity (CDA). The CDA set-size effect during retention mediated the effect between the 1064-nm tPBM and subsequent WM capacity. The behavioral benefits and the corresponding changes in the CDA set-size effect were absent with tPBM at a wavelength of 852 nm or with stimulation of the left PFC. Our findings provide converging evidence that 1064-nm tPBM applied to the right PFC can improve WM capacity.
... All these published reports strongly support that tPBM facilitates the photo-oxidization of [2,[25][26][27]. The enhancement of mitochondrial activity is expected to increase cerebral oxygen demand, blood flow, and blood oxygenation, as reported in recent literature [19,[28][29][30]. One of these studies suggested the modulation of vasomotion in the cerebral vasculature stimulated by nitricoxide release as another effect of tPBM [30]. ...
... Frequency-specific PSD bandwidths were then selected to cover the delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), beta (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), and gamma bands. Next, the mean power change at each of the five frequency bands (f ), ∆mPower f , during each of the three temporal segments (Stim1, Stim2, and post) was normalized to the last minute of its baseline (pre), as expressed [38]: ...
... Topographic maps of group-averaged (n = 45), baseline-normalized, and sham-subtracted changes in ∆mPowerss (see equation(2)) in delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), beta(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), and gamma (30-70 Hz) bands during the first 4 min of tPBM (Stim1), second 4 min of tPBM (Stim2), and post tPBM period. Also, statistical results after the cluster-based permutation testing are superimposed in each topographical map, showing significant differences in ∆mPower between the tPBM and sham stimulations during respective three time segments and in five frequency bands with corrected significance levels of p < 0.05 (×) and p < 0.01 ( * ). ...
Objective:
Transcranial photobiomodulation (tPBM) has shown promising benefits, including cognitive improvement, in healthy humans and in patients with Alzheimer's disease. In this study, we aimed to identify key cortical regions that present significant changes caused by tPBM in the electroencephalogram (EEG) oscillation powers and functional connectivity in the healthy human brain.
Approach:
A 64-channel EEG was recorded from 45 healthy participants during a 13-min period consisting of a 2-min baseline, 8-min tPBM/sham intervention, and 3-min recovery. After pre-processing and normalizing the EEG data at the five EEG rhythms, cluster-based permutation tests were performed for multiple comparisons of spectral power topographies, followed by graph-theory analysis (GTA) as a topological approach for quantification of brain connectivity metrics at global and nodal/cluster levels.
Main results:
EEG power enhancement was observed in clusters of channels over the frontoparietal regions in the alpha band and the centroparietal regions in the beta band. The global measures of the network revealed a reduction in synchronization, global efficiency, and small-worldness of beta band connectivity, implying an enhancement of brain network complexity. In addition, in the beta band, nodal graphical analysis demonstrated significant increases in local information integration and centrality over the frontal clusters, accompanied by a decrease in segregation over the bilateral frontal, left parietal, and left occipital regions.
Significance:
Frontal tPBM increased EEG alpha and beta powers in the frontal-central-parietal regions, enhanced the complexity of the global beta-wave brain network, and augmented local information flow and integration of beta oscillations across prefrontal cortical regions. This study sheds light on the potential link between electrophysiological effects and human cognitive improvement induced by tPBM.
... , especially in the human prefrontal cortex [7,9,169]. Furthermore, 1064 nm tPBM delivered to the right prefrontal cortex can alter the brain's hemodynamic, metabolic, electrophysiological functional connectivity at rest [43,105,170]. ...
... The significant increase in oxyhemoglobin ISO spectral amplitude (SAHbO) over the endogenic band in response to all three tPBM conditions ( figure 4.2(a)) ipsilateral to stimulation, implies that tPBM can significantly excite cerebral hemodynamic activity originated in endothelial oscillations over the stimulation site. This observation, which is independent of laser wavelength and location is in great agreement with several studies showing an increase in Δ[HbO] and its ISO spectral amplitude during and after tPBM with various laser/LED wavelengths and tissues [9,12,43,170,174]. We have also shown in another study that the upregulation of SAHbO in the endogenic band is because tPBM (specifically 1064nm laser) releases nitric oxide (NO) leading to vessel dilation [175] which seems to be the case for all examined wavelengths and locations in this study. ...
... In addition, improvement in cognitive activity and treatment of different neurological disorders have been reported during and after the employment of lowintensity light-emitting diode (LED) or laser on the human brain, especially on the prefrontal cortex [2,7,9,47,168,169]. Furthermore, it is shown that tPBM with different wavelengths and locations can alter the brain's hemodynamic, metabolic, and electrophysiological functional connectivity and MVC at rest [43,105,170,181]. ...
Transcranial photobiomodulation (tPBM) targets the human brain with near-infrared (NIR) light and is shown to affect human cognitive performance and neural electrophysiological activity as well as concentration changes of oxidized cytochrome-c-oxidase ([CCO]) and hemoglobin oxygenation ([HbO]) in human brain.
Brain topographical connectivity, which shows the communication between regions of the brain, and its alteration can be assessed to quantify the effects of external stimuli, diseases, and cognitive decline, in resting-state or task-based measurements. Furthermore, understanding the interactions between different physiological representations of neural activity, namely electrophysiological, hemodynamic, and metabolic signals in the human brain, has been an important topic among researchers in recent decades. In my doctoral study, neurophysiological networks were constructed using frequency-domain analyses on oscillations of electroencephalogram (EEG), [CCO], and [HbO] time series that were acquired by a portable EEG and 2-channel broadband near-infrared spectroscopy (2-bbNIRS).
Specifically, my dissertation included three aims. The first one was to examine how tPBM altered the topographical connectivity in the electrophysiological oscillations of the resting human brain. As the first step, I defined and found key regions and clusters in the EEG sensor space that were affected the most by tPBM during and after the stimulation using both cluster-based power analysis and graph-based connectivity analysis. The results showed that the right prefrontal 1064-nm tPBM modulates several global and regional electrophysiological networks by shifting the information path towards frontal regions, especially in the beta band. For the second aim, I performed 2-bbNIRS measurements from 26 healthy humans and developed a methodology that enabled quantification of the infra-slow oscillation (ISO) power and connectivity between bilateral frontal regions of the human brain in resting state and in response to frontal tPBM stimulation at different sites and laser wavelengths. As the result, several stable and consistent features were extracted in the resting state of 26 young healthy adults. Moreover, these features were used to reveal some effects of tPBM on prefrontal metabolism and hemodynamics, while illustrating the similarities and differences between different stimulation conditions. Finally, the third aim was to investigate the resting-state prefrontal physiological network and the corresponding modulation in response to left frontal 800-nm tPBM by determining the effective connectivity/coupling between each pair of the electrophysiological, hemodynamic, and metabolic ISO of the human brain. Complementary to the previous studies, my study showed that prefrontal tPBM not only modulates the information path between two locations of the prefrontal cortex, it can also induce unilateral alterations in interactions between neural activity, hemodynamics, and metabolism. Overall, my dissertation shed light on the mechanism of action of prefrontal tPBM.
