Abstract
The standard Gaussian function is proposed for the hemodynamic modulation function (HDMF) of functional magnetic resonance imaging (fMRI) time‐series. Unlike previously proposed parametric models, the Gaussian model accounts independently for the delay and dispersion of the hemodynamic responses and provides a more flexible and mathematically convenient model. A suboptimal noniterative scheme to estimate the hemodynamic parameters is presented. The ability of the Gaussian function to represent the HDMF of brain activation is compared with Poisson and Gamma models. The proposed model seems valid because the lag and dispersion values of hemodynamic responses rendered by the Gaussian model are in the ranges of their previously reported values in recent optical and fMR imaging studies.
An extension of multiple regression analysis to incorporate the HDMF is presented. The detected activity patterns exhibit improvements with hemodynamic correction. The proposed model and efficient parameter estimation scheme facilitated the investigation of variability of hemodynamic parameters of human brain activation. The hemodynamic parameters estimated over different brain regions and across different stimuli showed significant differences. Measurement of hemodynamic parameters over the brain during sensory or cognitive stimulation may reveal vital information on physiological events accompanying neuronal activation and functional variability of the human brain, and should lead to the investigation of more accurate and complex models. Hum. Brain Mapping 6:283–300, 1998. © 1998 Wiley‐Liss, Inc.
Keywords: brain imaging, blood‐oxygen‐level‐dependent contrast, functional magnetic resonance imaging, hemodynamic response function, multiple regression
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References
- Bandettini PA, Jesmanowicz A, Wong EC, Hyde JS (1993): Processing strategies for time‐course data sets in functional MRI of human brain. Magn Reson Med 30: 161–173. [DOI] [PubMed] [Google Scholar]
- Bandettini PA, Wong EC, Jesmanowicz A, Hinks RS, Hyde JS (1994): Spin‐echo and gradient‐echo EPI of human brain activation using BOLD contrast: Acomparative study at 1.5T. NMR Biomed 7: 12–20. [DOI] [PubMed] [Google Scholar]
- Belliveau JW, Kennedy DN, McKinstry RC, Buchbinder BR, Weisskoff RM, Cohen MS, Vevea JM, Brady TJ, Rosen BR (1991): Functional mapping of the human cortex by magnetic resonance imaging. Science 254: 716–719. [DOI] [PubMed] [Google Scholar]
- Blamire AM, Ogawa S, Ugurbil K, Rothman D, McCarthy G, Ellermann JM, Hyder F, Rattner Z, Shulman RG (1992): Dynamic mapping of the human visual cortex by high‐speed magnetic resonance imaging. Proc Natl Acad Sci USA 89: 11069–11073. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brigham EO (1988): The Fast Fourier Transform and Its Applications, Englewood Cliffs: Prentice Hall. [Google Scholar]
- Bullmore E, Brammer M, Williams SCR, Rabe‐Hesketh S, Janot N, David A, Mellers J, Howard R, Sham P (1996): Statistical methods of estimation and inference for functional MR image analysis. Magn Reson Med 35: 261–277. [DOI] [PubMed] [Google Scholar]
- Cerf B, Van de Moortele E, Giacomini E, MacLeod P, Faurion D, Le Bihan D (1996): Correlation of perception to temporal variations of fMRI signal: A taste study Proceedings of the Fourth Meeting of the International Society for Magnetic Resonance in Medicine, Berkeley: International Society for Magnetic Resonance in Medicine, p. 477. [Google Scholar]
- Cohen MS (1997): Parametric analysis of fMRI data using linear systems methods. Neuroimage 6: 93–103. [DOI] [PubMed] [Google Scholar]
- Duyn JH, Moonen CTW, van Yperen GH, de Boer RW, Luyten PR (1994): Inflow versus deoxyhemoglobin effects in BOLD functional MRI using gradient echoes at 1.5T. NMR Biomed 7: 83–88. [DOI] [PubMed] [Google Scholar]
- Engel SA, Rumelhart DE, Wandell BA, Lee AT, Glover GH, Chichilnisky E‐J, Shadlen MN (1994): fMRI of human visual cortex. Nature 369: 525. [DOI] [PubMed] [Google Scholar]
- Ernst T, Henning J (1994): Observation of fast response in functional MR. Magn Reson Med 32: 146–149. [DOI] [PubMed] [Google Scholar]
- Fox PT, Raichle ME (1986): Focal physiological uncoupling of erebral blood flow and oxidative metabolism during somatosensory stimulation in human subjects. Proc Natl Acad Sci USA 83: 1140–1144. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fox PT, Raichle ME, Mintun MA, Dence C (1988): Nonoxidative glucose consumption during focal physiologic neural activity. Science 241: 462–464. [DOI] [PubMed] [Google Scholar]
- Frahm J, Merboldt K‐D, Hanicke W, Kleinschmidt A, Boecker H (1994): Brain or vein—Oxygenation of flow? On signal physiology in functional MRI of human brain activation. NMR Biomed 7: 45–53. [DOI] [PubMed] [Google Scholar]
- Friston KJ, Worsley KJ, Frackowiak RSJ, Mazziotta JC, Evans AC (1994a): Assessing the significance of focal activations using their spatial extent. Hum Brain Mapp 1: 210–220. [DOI] [PubMed] [Google Scholar]
- Friston KJ, Jezzard P, Turner R (1994b): Analysis of functional MRI time‐series. Hum Brain Mapp 1: 153–171. [Google Scholar]
- Friston KJ, Holmes AP, Worsley KJ, Poline JB, Frith CD, Frackowiak RSJ (1995a): Statistical parametric maps in functional imaging: A general linear approach. Hum Brain Mapp 2: 189–210. [Google Scholar]
- Friston KJ, Holmes AP, Poline J‐B, Grasby PJ, Williams CR, Frackowiak SJ, Turner R (1995b): Analysis of fMRI time‐series revisited. Neuroimage 2: 45–53. [DOI] [PubMed] [Google Scholar]
- Friston KJ, Williams S, Howard R, Frackowiak RSJ, Turner R (1996): Movement‐related effects in fMRI time‐series. Magn Reson Med 35: 346–355. [DOI] [PubMed] [Google Scholar]
- Frostig RD, Lieeke EE, Ts'o YD, Grinvald A (1990): Cortical functional architecture and local coupling between neuronal activity and the microcirculation revealed by in vivo high‐resolution optical imaging of intrinsic signal. Proc Natl Acad Sci USA 87: 6082–6086. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jueptner M, Weiller C (1995): Review: Does measurement of regional cerebral blood flow reflect synaptic activity? Implications for PET and fMRI. Neuroimage 2: 148–156. [DOI] [PubMed] [Google Scholar]
- Kruggel F, Lohmann G (1996): BRIAN—A toolkit for the analysis of multimodal brain data sets In: Lemke HV, Inamura K, Jaffe CC, Vannier MW. (eds): Proceedings of the Computer Assisted Radiology (CAR 96). Berlin: Springer‐Verlag, pp 323–328. [Google Scholar]
- Kwong KK, Belliveau JW, Chesler DA, Goldberg IE, Weisskoff RM, Poncelet BP, Kennedy DN, Hoppel BE, Cohen MS, Turner R, Cheng H‐M, Brady TJ, Rosen BR (1992): Dynamic magnetic resonance imaging of human brain activity during primary sensory stimulation. Proc Natl Acad Sci USA 89: 5675–5679. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lange N, Zeger SL (1997): Non‐linear Fourier time series analysis for human brain mapping by functional magnetic resonance imaging. J R Stat Soc Appl Stat 46: 1–29. [Google Scholar]
- Lee AT, Glover GH, Meyer GH (1995): Discrimination of large venous vessels in time‐course spiral blood‐oxygen‐level‐dependent magnetic resonance functional neuroimaging. Magn Reson Med 33: 745–754. [DOI] [PubMed] [Google Scholar]
- Maisog JM, Clark V, Courtney S, Haxby J (1995): Estimating the hemodynamic response and effective degrees of freedom in functional MRI time series. First International Conference on Functional Mapping of the Human Brain Abstracts, Supplement 1, p 147.
- McCarthy G, Blamire AM, Rothman DL, Gruetter R, Shulman RG (1993): Echo‐planar magnetic resonance imaging studies of frontal cortex activation during word generation in humans. Proc Natl Acad Sci USA 90: 4952–4956. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Menon RS, Ogawa S, Tank DW, Ugurbil K (1993): 4 Tesla gradient recalled echo characteristics of photic stimulation‐induced signal changes in the human primary visual cortex. Magn Reson Med 30: 380–386. [DOI] [PubMed] [Google Scholar]
- Menon RS, Ogawa S, Hu X, Strupp JP, Anderson P, Ugurbil K (1995): BOLD based functional MRI at 4 Tesla includes a capillary bet contribution: Echo‐planar imaging correlates with previous optical imaging using intrinsic signals. Magn Reson Med 33: 453–459. [DOI] [PubMed] [Google Scholar]
- Nielsen FA, Hansen LK, Toft P, Goutte C, Lange N, Strother SC, Morch N, Svarer C, Savoy R, Rosen B, Rostrup E, Born P (1997): Comparison of two convolution models for fMRI time series.
- Toga A., Frachouide RSY, Mazzotta JC. (Eds.) Third International Conference on Functional Mapping of the Human Brain, San Diego: Academic Press, p. 473. [Google Scholar]
- Ogawa S, Tank DW, Menon R, Ellermann JM, Kim S‐G, Merkle H, Ugurbil K (1992): Intrinsic signal changes accompanying sensory stimulation: Functional brain mapping with magnetic resonance imaging. Proc Natl Acad Sci USA 89: 5951–5955. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ogawa S, Menon RS, Tank DW, Kim S‐G, Merkle H, Ellermann JM, Ugurbil K (1993): Functional brain mapping by blood oxygenation level‐dependent contrast magnetic resonance imaging. Biophys J 64: 803–812. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Papoulis A (1991): Probability, Random Variables, and Stochastic Processes, Third Edition, New York: McGraw‐Hill, Inc. [Google Scholar]
- Press WH, Teukolsky SA, Vetterling WT, Flamery BP (1994): Numerical Recipies in C, Cambridge: Cambridge University Press. [Google Scholar]
- Raichle ME, Grubb RL, Gado MH, Eichling JO, Ter‐Pogossian MM (1976): Correlation between regional cerebral blood flow and oxidative metabolism. Arch Neurol 33: 523–526. [DOI] [PubMed] [Google Scholar]
- Rajapakse JC, Kruggel F (1997): Neuronal and hemodynamic responses from fMRI time‐series. Proceedings of International Conference on Neural Information Processing, New Zealand.
- Rencher AC (1995): Methods of Multivariate Analysis, New York: John Wiley & Sons, Inc., p 360. [Google Scholar]
- Turner R, Jezzard P, Wen H, Kwong KK, Le Bihan D, Zeffiro T, Balaban RS (1993): Functional mapping of the human visual cortex at 4 and 1.5 Tesla using deoxygenation contrast EPI. Magn Reson Med 29: 277–279. [DOI] [PubMed] [Google Scholar]
- Singh M, Kim T, Kim H, Khosla D (1995): Separation of veins from activated brain tissue in functional magnetic resonance images at 1.5T. IEEE Trans Nucl Sci 42: 1338–1340. [Google Scholar]
- Sorenson JA, Wang X (1997): Problems in estimating hemodynamic response parameters from fMRI data. Hum Brain Mapp 4: 265–272. [DOI] [PubMed] [Google Scholar]
- Van de Moortele PF, Lobel E, Paradis AL, Le Bihan D (1997): Brain activation analysis of EPI fMRI time series needs correction for slice dependent phase shifts Proceedings of the Fifth Meeting of the International Society for Magnetic Resonance in Medicine, Berkeley: International Society for Magnetic Resonance in Medicine, p. 129. [Google Scholar]
- Villringer A, Dirnagl U (1995): Coupling of brain activity and cerebral blood flow: Basis of functional neuroimaging. Cerebrovasc Brain Metab Rev 7: 240–276. [PubMed] [Google Scholar]
- Worsley KJ, Friston KJ (1995): Analysis of fMRI time‐series revisited—again. Neuroimage 2: 173–181. [DOI] [PubMed] [Google Scholar]