2016/4/12 Blood oxygen level dependence change(BOLD) fMRI时间序列 16
2016/4/12 16 Blood oxygen level dependence change (BOLD) Resting Activated fMRI时间序列
2016/4/12 Blood oxygen level dependence change(BOLD) 19% 20 30 Time after stimulus onset(seconds)
2016/4/12 17 Blood oxygen level dependence change (BOLD) Duong, T.Q., Kim D.S., Ugurbil, K., and Kim, S.G. (2000). Spatiotemporal dynamics of the BOLD fMRI signals: Toward mapping submillimeter cortical columns using the early negative response. Magn. Reson. Med. 44:231-242. stimulus one set Oxygen level decrease Oxygen level increase by compensation W. W. Norton
2016/4/12 fMRI信号的神经解释 问题：MRI信号是什么东西？？ ·神经信号的变化是迅速 的 ·BOLD(RMI)信号的 变化是缓慢的 ·两者如何统一？ ·MRI信号是否只是和血 流有关？ 是否只具有生理学意义？ DavidJ.Heeger and David Ress,1,Nature 18
2016/4/12 18 fMRI信号的神经解释 问题：fMRI信号是什么东西？？ • 神经信号的变化是迅速 的 • BOLD（fRMI）信号的 变化是缓慢的 • 两者如何统一？ • fMRI信号是否只是和血 流有关？ • 是否只具有生理学意义？ David J. Heeger and David Ress, 2001, Nature
2016/4/12 fMRI的神经解释：Boynton的线性模型 fMRI的神经解释：Logothetis的研究 19
2016/4/12 19 fMRI的神经解释：Boynton的线性模型 Boynton, G. M., Engel, S. A., Glover, G. H. & Heeger, D. J. Linear systems analysis of functional magnetic resonance imaging in human V1. J. Neurosci. 16, 4207–4221 (1996). fMRI的神经解释：Logothetis的研究 Logothetis, N. K., Pauls, J., Augath, M., Trinath, T. & Oeltermann, A. Neurophysiological investigation of the basis of the fMRI signal. Nature 412, 150–157 (2001)
2016/4/12 LFP and MUA的一般知识 68.8estcaeasd2en82oae8npoeiasfom n y pick up the activity of several nearby cells rcrmment BOLD增强在时间上和LFP、MUA的 增强是有关的 44 ater 2-4s stimulu tBOLD may reflect e the neural activity elated to the input anc rather than the spiking activity 20
2016/4/12 20 LFP and MUA的一般知识 • An electrode small enough allows indirect observation and recording of action potentials from a single cell, and is termed single-unit recording. Depending on the preparation and precise placement, an extracellular configuration may pick up the activity of several nearby cells simultaneously, and this is termed multi-unit recording （for MUA）. • As electrode size increases, the resolving power decreases. Larger electrodes are sensitive only to the net activity of many cells, termed local field potentials (LFP). • 25% of MUA show a transient response returning to baseline after 2‐4s. • Conversely, LFP was always elevated for the duration of the stimulus. • Suggests that BOLD may reflect more the neural activity related to the input and local processing in any given area, rather than the spiking activity commonly thought of as the output of an area. BOLD增强在时间上和LFP、MUA的 增强是有关的