Physiological Effects of Continuous Colored Light Exposure on Mayer Wave Activity in Cerebral Hemodynamics: A Functional Near-Infrared Spectroscopy (fNIRS) Study

Adv Exp Med Biol. 2017;977:277-283. doi: 10.1007/978-3-319-55231-6_38.

Abstract

We are increasingly exposed to colored light, but its impact on human physiology is not yet extensively investigated. In the present study we aimed to determine the effects of colored light on human cerebral Mayer wave activity (MWA). We measured oxy- ([O2Hb]), deoxy- ([HHb]), total hemoglobin ([tHb]) concentrations and tissue oxygen saturation (StO2) by functional near-infrared spectroscopy (fNIRS) in the left and right pre-frontal cortex (L-PFC, R-PFC) of 17 subjects (median age: 29 years, 6 women). In a randomized crossover design subjects were exposed to blue, red, green, and yellow LED light for 10 min. Pre-light (8 min, baseline) and post-light (15 min, recovery) conditions were darkness. MWA was calculated from band-pass filtered fNIRS signals (~0.08-0.12 Hz). The medians from the last 3 min of each period (baseline, light exposure, recovery) were statistically analyzed. MWA was increased during red and green light vs. baseline and after blue light exposure in recovery in the L-PFC. MWA differed depending on the chosen frequency range, filter design, and type of signals to analyze (raw intensity, hemoglobin signal from multi-distance method or modified Beer-Lambert law, or within hemoglobin signals).

Keywords: Brain; Colored light exposure; Functional near-infrared spectroscopy; Mayer wave activity.

MeSH terms

  • Adult
  • Aged
  • Cerebrovascular Circulation / radiation effects*
  • Color
  • Cross-Over Studies
  • Female
  • Hemodynamics / radiation effects*
  • Hemoglobins / analysis
  • Humans
  • Light*
  • Male
  • Middle Aged
  • Oxygen / analysis
  • Prefrontal Cortex / blood supply*
  • Random Allocation
  • Spectroscopy, Near-Infrared

Substances

  • Hemoglobins
  • deoxyhemoglobin
  • Oxygen