虽然这个较差的时间分辨率是fMRI与生俱来的,但我们仍然发展出了一些解决办法。 其中之一就是时间超敏度(Temporal hyperacuity)的方法,它的一种做法是将同一种事件都进行平均,那么我们就能够以100-200msec的延迟来检测到平均反应的差异。这种方法的出现得益于快速采样方法的出现,能够在100-200msec内得到整个大脑的图像。
在fMRI技术中,ALS fMRI(arterial spin labeling fMRI,动脉自旋标记fMRI)在时间稳定性方面非常好,即它可以比较间隔时间长达几天或十几天的两种激活状态。 而BOLD fMRI则介于这些技术之间,其空间分辨率上至整个大脑,下至小于1mm,而时间分辨率通常是几秒钟到一两分钟,而随着技术的进步和新技术的出现,我们有可能进一步...
The temporal resolution of EEG is excellent, managing to capture neural events in the order of milliseconds. On the other hand, its spatial resolution lacks precision. Conversely, fMRI offers high spatial resolution, typically on the order of mm 3 . However, it has limited temporal resolution (...
第一周:fMRI简介,data acquisition and reconstruction 大致分为两类: Structural brain imaging(CAT,MRI,PET) Functional brain imaging(PET,fMRI,EEG,MEG) 每个方法都有自己的spatial resolution,temporal resolutionandinvasiveness. Functional MRI provides a nice balance between these properties and has become the ...
Ugurbil, K., Xu, J., Auerbach, E.J., Moeller, S., Vu, A.T.,Duarte-Carvajalino, J.M., Lenglet, C., Wu, X., Schmitter, S., Van de Moortele,P.F., et al.(2013). Pushing spatialand temporal resolution for functional and diffusion MRI in the HumanConnectome Project. NeuroIma...
This method makes use of strong magnets to create maps of brain activity by detecting changes in blood flow that are coupled to neuronal activation. This imaging technique has excellent spatial and good temporal resolution, and is noninvasive, since it does not require injections or involve exposin...
预处理步骤包括:可视化(Visualization)、去伪影(Artifact removal)、时间配准(Slice time correction)、头动校正(Motion correction)、生理噪音校正(Correction for physiological effect)、结构功能配准(Co-registration)、标准化(Normalization)和时空间滤波(Spatial and temporal filtering)。
of the CAP framework, its direct association with a directly quantifiable physiological property, as well as its high temporal and spatial resolution are perfectly suited to parsimoniously, yet comprehensively describe the dynamic organization of spontaneous network activity....
Ultra-high-field functional magnetic resonance imaging (fMRI) offers a way to new insights while increasing the spatial and temporal resolution. However, a crucial concern in 7T human MRI is the increase in power deposition, supervised through the specific absorption rate (SAR). The SAR limitation...
The two measurements can be calculated at both spatial and temporal level. Note that for temporally detrended data, the temporal SNR (or functional SNR) is also called Signal-to-Fluctuation-Noise Ratio (SFNR). Temporal CNR is also signal sentivity. ...