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Philos Trans R Soc Lond B Biol Sci. 1997 June 29; 352(1354): 727–735.
PMCID: PMC1691951

Measurements of scattering and absorption changes in muscle and brain.

Abstract

Non-invasive techniques for the study of human brain function based on changes of the haemoglobin content or on changes of haemoglobin saturation have recently been proposed. Among the new methods, near-infrared transmission measurements may have significant advantages and complement well-established methods such as functional magnetic resonance imaging and positron emission tomography. Near-infrared measurements can be very fast, comparable in speed to electrophysiological measurements, bur are better localized. We will present the demonstration of measurements of millisecond signals due to brain activity in humans following stimulation of the visual cortex. However, major unresolved questions remain about the origin of the signals observed. Optical measurements on exposed cortex in animals show that both the absorption and the scattering coefficient are affected by neural activity. Model calculations show that the signals we detected may originate from rapid changes of the scattering coefficient in a region about 1 to 2 cm below the scalp. We discuss our measurement protocol, which is based on a frequency-domain instrument, and the algorithm to separate the absorption from the scattering contribution in the overall response. Our method produces excellent separation between scattering and absorption in relatively homogeneous masses such as large muscles. The extrapolation of our measurement protocol to a complex structure such as the human head is critically evaluated.

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Selected References

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  • Benaron DA, Stevenson DK. Optical time-of-flight and absorbance imaging of biologic media. Science. 1993 Mar 5;259(5100):1463–1466. [PubMed]
  • Belliveau JW, Kennedy DN, Jr, McKinstry RC, Buchbinder BR, Weisskoff RM, Cohen MS, Vevea JM, Brady TJ, Rosen BR. Functional mapping of the human visual cortex by magnetic resonance imaging. Science. 1991 Nov 1;254(5032):716–719. [PubMed]
  • Bonner RF, Nossal R, Havlin S, Weiss GH. Model for photon migration in turbid biological media. J Opt Soc Am A. 1987 Mar;4(3):423–432. [PubMed]
  • Chance B. Time resolved spectroscopic (TRS) and continuous wave spectroscopic (CWS) studies of photon migration in human arms and limbs. Adv Exp Med Biol. 1989;248:21–31. [PubMed]
  • Chance B. Optical method. Annu Rev Biophys Biophys Chem. 1991;20:1–28. [PubMed]
  • Federico P, Borg SG, Salkauskus AG, MacVicar BA. Mapping patterns of neuronal activity and seizure propagation by imaging intrinsic optical signals in the isolated whole brain of the guinea-pig. Neuroscience. 1994 Feb;58(3):461–480. [PubMed]
  • Firbank M, Arridge SR, Schweiger M, Delpy DT. An investigation of light transport through scattering bodies with non-scattering regions. Phys Med Biol. 1996 Apr;41(4):767–783. [PubMed]
  • Fishkin JB, Gratton E. Propagation of photon-density waves in strongly scattering media containing an absorbing semi-infinite plane bounded by a straight edge. J Opt Soc Am A. 1993 Jan;10(1):127–140. [PubMed]
  • Frostig RD, Lieke EE, Ts'o DY, Grinvald A. Cortical functional architecture and local coupling between neuronal activity and the microcirculation revealed by in vivo high-resolution optical imaging of intrinsic signals. Proc Natl Acad Sci U S A. 1990 Aug;87(16):6082–6086. [PubMed]
  • Gratton G, Corballis PM. Removing the heart from the brain: compensation for the pulse artifact in the photon migration signal. Psychophysiology. 1995 May;32(3):292–299. [PubMed]
  • Gratton G, Corballis PM, Cho E, Fabiani M, Hood DC. Shades of gray matter: noninvasive optical images of human brain responses during visual stimulation. Psychophysiology. 1995 Sep;32(5):505–509. [PubMed]
  • Gratton E, Limkeman M. A continuously variable frequency cross-correlation phase fluorometer with picosecond resolution. Biophys J. 1983 Dec;44(3):315–324. [PubMed]
  • Gratton G, Maier JS, Fabiani M, Mantulin WW, Gratton E. Feasibility of intracranial near-infrared optical scanning. Psychophysiology. 1994 Mar;31(2):211–215. [PubMed]
  • Grinvald A, Lieke E, Frostig RD, Gilbert CD, Wiesel TN. Functional architecture of cortex revealed by optical imaging of intrinsic signals. Nature. 324(6095):361–364. [PubMed]
  • Holthoff K, Dodt HU, Witte OW. Changes in intrinsic optical signal of rat neocortical slices following afferent stimulation. Neurosci Lett. 1994 Oct 24;180(2):227–230. [PubMed]
  • Hoshi Y, Tamura M. Dynamic multichannel near-infrared optical imaging of human brain activity. J Appl Physiol (1985) 1993 Oct;75(4):1842–1846. [PubMed]
  • Jennings JR, Choi S. Methodology. An arterial to peripheral pulse wave velocity measure. Psychophysiology. 1983 Jul;20(4):410–418. [PubMed]
  • Maki A, Yamashita Y, Ito Y, Watanabe E, Mayanagi Y, Koizumi H. Spatial and temporal analysis of human motor activity using noninvasive NIR topography. Med Phys. 1995 Dec;22(12):1997–2005. [PubMed]
  • Meek JH, Elwell CE, Khan MJ, Romaya J, Wyatt JS, Delpy DT, Zeki S. Regional changes in cerebral haemodynamics as a result of a visual stimulus measured by near infrared spectroscopy. Proc Biol Sci. 1995 Sep 22;261(1362):351–356. [PubMed]
  • O'Leary MA, Boas DA, Chance B, Yodh AG. Refraction of diffuse photon density waves. Phys Rev Lett. 1992 Nov 2;69(18):2658–2661. [PubMed]
  • Stepnoski RA, LaPorta A, Raccuia-Behling F, Blonder GE, Slusher RE, Kleinfeld D. Noninvasive detection of changes in membrane potential in cultured neurons by light scattering. Proc Natl Acad Sci U S A. 1991 Nov 1;88(21):9382–9386. [PubMed]
  • Villringer A, Dirnagl U. Coupling of brain activity and cerebral blood flow: basis of functional neuroimaging. Cerebrovasc Brain Metab Rev. 1995 Fall;7(3):240–276. [PubMed]
  • Wilson BC, Patterson MS, Flock ST. Indirect versus direct techniques for the measurement of the optical properties of tissues. Photochem Photobiol. 1987 Nov;46(5):601–608. [PubMed]

Articles from Philosophical Transactions of the Royal Society B: Biological Sciences are provided here courtesy of The Royal Society