Long-Term Changes in Optical Properties ( μa, μ's, μeff and DPF) of Human Head Tissue During Functional Neuroimaging Experiments.

Long-Term Changes in Optical Properties (μa, μ's, μeff and DPF) of Human Head Tissue During Functional Neuroimaging Experiments. Adv Exp Med Biol. 2018;1072:331-337 Authors: Zohdi H, Scholkmann F, Nasseri N, Wolf U Abstract Frequency-domain near-infrared spectroscopy (FD-NIRS) enables to measure absolute optical properties (i.e. the absorption coefficient, μa, and the reduced scattering coefficient, [Formula: see text]) of the brain tissue. The aim of this study was to investigate how the optical properties changed during the course of a functional NIRS experiment. The analyzed dataset comprised of FD-NIRS measurements of 14 healthy subjects (9 males, 5 females, aged: 33.4 ± 10.5 years, range: 24-57 years old). Each measurement lasted 33 min, i.e. 8 min baseline in darkness, 10 min intermittent light stimulation, and 15 min recovery in darkness. Optical tissue properties were obtained bilaterally over the prefrontal cortex (PFC) and visual cortex (VC) with FD-NIRS (Imagent, ISS Inc., USA). Changes in μa and [Formula: see text] were directly measured and two parameters were calculated, i.e. the differential pathlength factor (DPF) and the effective attenuation coefficient (μeff). Differences in the behavior of the optical changes were observed when comparing group-averaged data versus single datasets: no clear overall trend was presented in the group data, whereas a clear long-term trend was visible in almost all of the sing...
Source: Adv Data - Category: Epidemiology Authors: Tags: Adv Exp Med Biol Source Type: research