Transcranial laser stimulation improves human cerebral oxygenation

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

Background and Objective

Transcranial laser stimulation of the brain with near‐infrared light is a novel form of non‐invasive photobiomodulation or low‐level laser therapy (LLLT) that has shown therapeutic potential in a variety of neurological and psychological conditions. Understanding of its neurophysiological effects is essential for mechanistic study and treatment evaluation. This study investigated how transcranial laser stimulation influences cerebral hemodynamics and oxygenation in the human brain in vivo using functional near‐infrared spectroscopy (fNIRS).

Materials and Methods

Two separate experiments were conducted in which 1,064‐nm laser stimulation was administered at (1) the center and (2) the right side of the forehead, respectively. The laser emitted at a power of 3.4 W and in an area of 13.6 cm ², corresponding to 0.25 W/cm ² irradiance. Stimulation duration was 10 minutes. Nine healthy male and female human participants of any ethnic background, in an age range of 18–40 years old were included in each experiment.

Results

In both experiments, transcranial laser stimulation induced an increase of oxygenated hemoglobin concentration (Δ[HbO ₂]) and a decrease of deoxygenated hemoglobin concentration (Δ[Hb]) in both cerebral hemispheres. Improvements in cerebral oxygenation were indicated by a significant increase of differential hemoglobin concentration (Δ[HbD] = Δ[HbO ₂] − Δ[Hb]). These effects increased in a dose‐dependent manner over time during laser stimulation (10 minutes) and persisted after laser stimulation (6 minutes). The total hemoglobin concentration (Δ[HbT] = Δ[HbO2] + Δ[Hb]) remained nearly unchanged in most cases.

Conclusion

Near‐infrared laser stimulation applied to the forehead can transcranially improve cerebral oxygenation in healthy humans. Lasers Surg. Med. 48:343–349, 2016. © 2016 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Related collections

Most cited references 24

Record: found
Abstract: found
Article: not found

Neurovascular coupling in the normal brain and in hypertension, stroke, and Alzheimer disease.

Hélène Girouard, Costantino Iadecola (2006)

The brain is critically dependent on a continuous supply of blood to function. Therefore, the cerebral vasculature is endowed with neurovascular control mechanisms that assure that the blood supply of the brain is commensurate to the energy needs of its cellular constituents. The regulation of cerebral blood flow (CBF) during brain activity involves the coordinated interaction of neurons, glia, and vascular cells. Thus, whereas neurons and glia generate the signals initiating the vasodilation, endothelial cells, pericytes, and smooth muscle cells act in concert to transduce these signals into carefully orchestrated vascular changes that lead to CBF increases focused to the activated area and temporally linked to the period of activation. Neurovascular coupling is disrupted in pathological conditions, such as hypertension, Alzheimer disease, and ischemic stroke. Consequently, CBF is no longer matched to the metabolic requirements of the tissue. This cerebrovascular dysregulation is mediated in large part by the deleterious action of reactive oxygen species on cerebral blood vessels. A major source of cerebral vascular radicals in models of hypertension and Alzheimer disease is the enzyme NADPH oxidase. These findings, collectively, highlight the importance of neurovascular coupling to the health of the normal brain and suggest a therapeutic target for improving brain function in pathologies associated with cerebrovascular dysfunction.

0 comments Cited 340 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

A temporal comparison of BOLD, ASL, and NIRS hemodynamic responses to motor stimuli in adult humans.

T J Huppert, R. D. HOGE, S G Diamond … (2006)

In this study, we have preformed simultaneous near-infrared spectroscopy (NIRS) along with BOLD (blood oxygen level dependent) and ASL (arterial spin labeling)-based fMRI during an event-related motor activity in human subjects in order to compare the temporal dynamics of the hemodynamic responses recorded in each method. These measurements have allowed us to examine the validity of the biophysical models underlying each modality and, as a result, gain greater insight into the hemodynamic responses to neuronal activation. Although prior studies have examined the relationships between these two methodologies through similar experiments, they have produced conflicting results in the literature for a variety of reasons. Here, by employing a short-duration, event-related motor task, we have been able to emphasize the subtle temporal differences between the hemodynamic parameters with a high contrast-to-noise ratio. As a result of this improved experimental design, we are able to report that the fMRI measured BOLD response is more correlated with the NIRS measure of deoxy-hemoglobin (R = 0.98; P < 10(-20)) than with oxy-hemoglobin (R = 0.71), or total hemoglobin (R = 0.53). This result was predicted from the theoretical grounds of the BOLD response and is in agreement with several previous works [Toronov, V.A.W., Choi, J.H., Wolf, M., Michalos, A., Gratton, E., Hueber, D., 2001. "Investigation of human brain hemodynamics by simultaneous near-infrared spectroscopy and functional magnetic resonance imaging." Med. Phys. 28 (4) 521-527.; MacIntosh, B.J., Klassen, L.M., Menon, R.S., 2003. "Transient hemodynamics during a breath hold challenge in a two part functional imaging study with simultaneous near-infrared spectroscopy in adult humans". NeuroImage 20 1246-1252.; Toronov, V.A.W., Walker, S., Gupta, R., Choi, J.H., Gratton, E., Hueber, D., Webb, A., 2003. "The roles of changes in deoxyhemoglobin concentration and regional cerebral blood volume in the fMRI BOLD signal" Neuroimage 19 (4) 1521-1531]. These data have also allowed us to examine more detailed measurement models of the fMRI signal and comment on the roles of the oxygen saturation and blood volume contributions to the BOLD response. In addition, we found high correlation between the NIRS measured total hemoglobin and ASL measured cerebral blood flow (R = 0.91; P < 10(-10)) and oxy-hemoglobin with flow (R = 0.83; P < 10(-05)) as predicted by the biophysical models. Finally, we note a significant amount of cross-modality, correlated, inter-subject variability in amplitude change and time-to-peak of the hemodynamic response. The observed co-variance in these parameters between subjects is in agreement with hemodynamic models and provides further support that fMRI and NIRS have similar vascular sensitivity.

0 comments Cited 221 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Photobiomodulation directly benefits primary neurons functionally inactivated by toxins: role of cytochrome c oxidase.

Britton Chance, Mary Kane, Harry Whelan … (2005)

Far red and near infrared (NIR) light promotes wound healing, but the mechanism is poorly understood. Our previous studies using 670 nm light-emitting diode (LED) arrays suggest that cytochrome c oxidase, a photoacceptor in the NIR range, plays an important role in therapeutic photobiomodulation. If this is true, then an irreversible inhibitor of cytochrome c oxidase, potassium cyanide (KCN), should compete with LED and reduce its beneficial effects. This hypothesis was tested on primary cultured neurons. LED treatment partially restored enzyme activity blocked by 10-100 microm KCN. It significantly reduced neuronal cell death induced by 300 microm KCN from 83.6 to 43.5%. However, at 1-100 mm KCN, the protective effects of LED decreased, and neuronal deaths increased. LED significantly restored neuronal ATP content only at 10 microm KCN but not at higher concentrations of KCN tested. Pretreatment with LED enhanced efficacy of LED during exposure to 10 or 100 microm KCN but did not restore enzyme activity to control levels. In contrast, LED was able to completely reverse the detrimental effect of tetrodotoxin, which only indirectly down-regulated enzyme levels. Among the wavelengths tested (670, 728, 770, 830, and 880 nm), the most effective ones (830 nm, 670 nm) paralleled the NIR absorption spectrum of oxidized cytochrome c oxidase, whereas the least effective wavelength, 728 nm, did not. The results are consistent with our hypothesis that the mechanism of photobiomodulation involves the up-regulation of cytochrome c oxidase, leading to increased energy metabolism in neurons functionally inactivated by toxins.

0 comments Cited 162 times – based on 0 reviews      Review now

Bookmark

All references

Author and article information

Journal

Journal ID (nlm-ta): Lasers Surg Med

Journal ID (iso-abbrev): Lasers Surg Med

Journal ID (doi): 10.1002/(ISSN)1096-9101

Journal ID (publisher-id): LSM

Title: Lasers in Surgery and Medicine

Publisher: John Wiley and Sons Inc. (Hoboken )

ISSN (Print): 0196-8092

ISSN (Electronic): 1096-9101

Publication date (Electronic): 12 January 2016

Publication date (Print): April 2016

Volume: 48

Issue: 4 ( doiID: 10.1002/lsm.v48.4 )

Pages: 343-349

Affiliations

[ ¹ ] Department of BioengineeringUniversity of Texas Arlington Texas 76010

[ ² ] Department of Psychology and Institute for NeuroscienceUniversity of Texas Austin Texas 78712

Author notes

[*] [* ] Correspondence to: F. Gonzalez‐Lima, PhD, Department of Psychology, University of Texas, 108 E. Dean Keeton Stop A8000, Austin, TX 78712. E‐mail: gonzalezlima@ 123456utexas.edu

Correspondence to: Hanli Liu, PhD, Department of Bioengineering, University of Texas, 500 UTA Blvd, Arlington, TX 76010. E‐mail: hanli@ 123456uta.edu

Article

Publisher ID: LSM22471

DOI: 10.1002/lsm.22471

PMC ID: 5066697

PubMed ID: 26817446

SO-VID: eb613cf3-6cc9-4f18-a75a-219e492412b7

License:

This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

History

Date accepted : 23 December 2015

Page count

Pages: 7

Custom metadata

source-schema-version-number 2.0

component-id lsm22471

cover-date April 2016

details-of-publishers-convertor Converter:WILEY_ML3GV2_TO_NLMPMC version:4.9.5 mode:remove_FC converted:17.10.2016

Keywords: functional near‐infrared spectroscopy (fnirs),low‐level laser therapy (lllt),photobiomodulation,brain tissue oxygenation

Data availability:

Keywords: functional near‐infrared spectroscopy (fnirs), low‐level laser therapy (lllt), photobiomodulation, brain tissue oxygenation

Transcranial laser stimulation improves human cerebral oxygenation

Read this article at

Abstract

Background and Objective

Materials and Methods

Results

Conclusion

Related collections

Probing cerebral hemodynamics with BOLD fMRI

Most cited references 24

Neurovascular coupling in the normal brain and in hypertension, stroke, and Alzheimer disease.

A temporal comparison of BOLD, ASL, and NIRS hemodynamic responses to motor stimuli in adult humans.

Photobiomodulation directly benefits primary neurons functionally inactivated by toxins: role of cytochrome c oxidase.

Author and article information

Journal

Affiliations

Author notes

Article

History

Page count

Categories

Custom metadata

Comments

Comment on this article

Similar content 501

Cited by 50

Most referenced authors 364