Introduction non neuronal sources of fluctuation (noise):
{"Image DocumentName": "Introduction non neuronal sources of fluctuation (noise):", "Image ImageDescription": "cardiac pulsation, respiration \uf0e0 physiological measured. changes in CO2 (Wise et al., 2004) magnetic noise, subjects head sinks\u2026 Noise reduction: Preprocessing: body, head correction... Global signal regression (GLM) filter out global signal. Fluctuation in signal can also be caused by changes in cardiac pulsation, respiration. These noise can be controlled by measuring these parameters. It has also been shown that changes in arterial carbon dioxide cause very low frequency fluctuations. And then you can blame the hardware and subject for more noise. There are several methods to reduce noise. To account for several potential sources of noise Global signal regression is very often performed. That means you average the time series over all voxels and use it as a regressor in a general linear model.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}