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

Abstract

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.

Water-Diffusion Slowdown in the Human Visual Cortex on Visual Stimulation Precedes Vascular Responses

“…rise times for the diffusion MRI, SE-BOLD MRI, GE-BOLD MRI, and total-Hb (NIRS) responses were 1.2 ± 0.1, 3.3 ± 0.9, 4.4 ± 0.3, and 2.1±0.6 secs, respectively ( Figure 6A). The rise times of the SE-BOLD and total-hemoglobin signals were faster than those of GE-BOLD, which was in agreement with several previous works (Hulvershorn et al, 2005;Huppert et al, 2006), but were statistically significantly longer than the diffusion MRI signal. Interestingly, differences in the decay times were even larger: 2.0±0.6, 6.2±0.5, 6.4±0.4, and 6.8±0.8 secs, for the diffusion MRI, SE-BOLD MRI, GE-BOLD, and totalHb responses, respectively ( Figure 6B).…”

“…However, the assumption of a nonvascular origin of the water-diffusion signal is a subject of controversy (Jin and Kim, 2008;Miller et al, 2007;Yacoub et al, 2008). Furthermore, vascular responses that are faster than BOLD signals have also been observed through measurements of the regional cerebral blood volume (rCBV) and the total local hemoglobin content (Huppert et al, 2006;Lu et al, 2003;Malonek et al, 1997).…”

Task complexity relates to activation of cortical motor areas during uni- and bimanual performance: A functional NIRS study

“…HHb concentration increases or decreases after stimulus onset. Similar discrepancies have been described further as partial volume effect (Boas et al, 2001, Strangman et al, 2002b, Huppert et al, 2006, Xu et al, 2007. Partial volume effect is the effect wherein insufficient image resolution leads to a mixing of different tissue types.…”

A perfusion fMRI investigation of thematic and categorical context effects in the spoken production of object names

“…Perfusion fMRI has several advantages over blood oxygen level dependent (BOLD) fMRI. For instance, the signal is more directly related to neural activity, arising approximately 1-2 s earlier than the peak BOLD response (see Cavusoglu et al, 2012;Huppert et al, 2006), it provides a quantitative estimate of signal change in absolute units, and it is demonstrably less sensitive to speech-related susceptibility artifacts (Kemeny et al, 2005; for reviews, see Detre et al, 2012;Liu & Brown, 2007 Oppenheim et al, 2010), additional signal changes in the right IFG and ACC are likely to be observed (Kuhl et al, 2007;Levy & Anderson, 2008;Wimber et al, 2009). Finally, unlike previous neuroimaging studies, we included presentation cycle as a factor in our analyses.…”