TY - JOUR
T1 - The spatiotemporal hemodynamic response function for depth-dependent functional imaging of human cortex
AU - Puckett, Alexander M.
AU - Aquino, Kevin M.
AU - Robinson, P.A.
AU - Breakspear, Michael
AU - Schira, Mark M.
PY - 2016/10/1
Y1 - 2016/10/1
N2 - The gray matter of human cortex is characterized by depth-dependent differences in neuronal activity and connections (Shipp, 2007) as well as in the associated vasculature (Duvernoy et al., 1981). The resolution limit of functional magnetic resonance imaging (fMRI) measurements is now below a millimeter, promising the non-invasive measurement of these properties in awake and behaving humans (Muckli et al., 2015; Olman et al., 2012; Ress et al., 2007). To advance this endeavor, we present a detailed spatiotemporal hemodynamic response function (HRF) reconstructed through the use of high-resolution, submillimeter fMRI. We decomposed the HRF into directions tangential and perpendicular to the cortical surface and found that key spatial properties of the HRF change significantly with depth from the cortical surface. Notably, we found that the spatial spread of the HRF increases linearly from 4.8 mm at the gray/white matter boundary to 6.6 mm near the cortical surface. Using a hemodynamic model, we posit that this effect can be explained by the depth profile of the cortical vasculature, and as such, must be taken into account to properly estimate the underlying neuronal responses at different cortical depths.
AB - The gray matter of human cortex is characterized by depth-dependent differences in neuronal activity and connections (Shipp, 2007) as well as in the associated vasculature (Duvernoy et al., 1981). The resolution limit of functional magnetic resonance imaging (fMRI) measurements is now below a millimeter, promising the non-invasive measurement of these properties in awake and behaving humans (Muckli et al., 2015; Olman et al., 2012; Ress et al., 2007). To advance this endeavor, we present a detailed spatiotemporal hemodynamic response function (HRF) reconstructed through the use of high-resolution, submillimeter fMRI. We decomposed the HRF into directions tangential and perpendicular to the cortical surface and found that key spatial properties of the HRF change significantly with depth from the cortical surface. Notably, we found that the spatial spread of the HRF increases linearly from 4.8 mm at the gray/white matter boundary to 6.6 mm near the cortical surface. Using a hemodynamic model, we posit that this effect can be explained by the depth profile of the cortical vasculature, and as such, must be taken into account to properly estimate the underlying neuronal responses at different cortical depths.
KW - fMRI
KW - Hemodynamic response
KW - High-resolution
KW - Human
KW - Layers
KW - Visual cortex
UR - http://www.scopus.com/inward/record.url?scp=84979021950&partnerID=8YFLogxK
U2 - 10.1016/j.neuroimage.2016.06.019
DO - 10.1016/j.neuroimage.2016.06.019
M3 - Article
C2 - 27321045
AN - SCOPUS:84979021950
SN - 1053-8119
VL - 139
SP - 240
EP - 248
JO - NeuroImage
JF - NeuroImage
ER -