Investigation of human brain hemodynamics by simultaneous near‐infrared spectroscopy and functional magnetic resonance imaging

Abstract

The aim of this study was to compare functional cerebral hemodynamic signals obtained simultaneously by near infrared spectroscopy ͑NIRS͒ and by functional magnetic resonance imaging ͑fMRI͒. The contribution of superficial layers ͑skin and skull͒ to the NIRS signal was also assessed. Both methods were used to generate functional maps of the motor cortex area during a periodic sequence of stimulation by finger motion and rest. In all subjects we found a good collocation of the brain activity centers revealed by both methods. We also found a high temporal correlation between the BOLD signal ͑fMRI͒ and the deoxy-hemoglobin concentration ͑NIRS͒ in the subjects who exhibited low fluctuations in superficial head tissues.

The roles of changes in deoxyhemoglobin concentration and regional cerebral blood volume in the fMRI BOLD signal

“…One possible explanation for these highly variable correlations obtained by Strangman et al (2002) were due to the near-infrared technique used in their study, which was a single source-detector method. Previously our group also used this technique (Toronov et al, 2001), and found that it is highly sensitive to superficial hemodynamic fluctuations in the scalp. These fluctuations bias the signals, thus reducing the correlation with the BOLD signal.…”

“…In recent years many NIRS studies have demonstrated that cerebral hemodynamic changes associated with functional brain activity can be assessed noninvasively in adult human subjects (Benaron and Stevenson, 1994;Obrig et al, 2000). Several types of brain activity have been studied, including motor activity Colier et al, 1999;Toronov et al, 2000Toronov et al, , 2001Franceschini et al, 2000), visual activation (Ruben et al, 1997;Kato et al, 1993), auditory stimulation (Sakatani et al, 1999), and the performance of different cognitive tasks (Chance et al, 1993;Villringer et al, 1993). Kleinschmidt et al (1996) were first to measure simultaneously the BOLD fMRI signal and hemoglobin changes using NIRS.…”

“…Kleinschmidt et al (1996) were first to measure simultaneously the BOLD fMRI signal and hemoglobin changes using NIRS. Our group then reported the first NIR mapping of functional hemodynamics in human motor cortex with simultaneous fMRI measurements (Toronov et al, 2001). Although NIRS cannot compete with fMRI in terms of spatial resolution, the unique biochemical specificity of NIRS makes it a perfect complementary method to resolve difficulties in the physiological interpretation of the BOLD signal (Villringer and Chance, 1997).…”

“…All previous NIRS measurements of cerebral hemodynamics have been performed by using a single sourcedetector pair (see, for example, Toronov et al, 2001). In this study the optical properties of tissue were obtained from the slopes of the modulation amplitude (AC) and phase of the harmonically modulated optical signals measured at several source-detector distances (Fantini et al, 1995).…”

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

“…• Some devices offer interfaces to allow for multi-modal imaging and have successfully been used for example in simultaneous measurements of fNIRI and MEG (Seki et al, 2012), EEG (Hebden et al, 2012;Leamy and Ward, 2010), fMRI (Habermehl et al, 2012a;Toronov et al, 2001;X. Zhang et al, 2005) and other modalities.…”