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Neuronal Correlates of Spontaneous Fluctuations in fMRI Signals in Monkey Visual Cortex: Implications for Functional Connectivity at Rest

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Shmuel,  A
Department Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Max Planck Society;
Max Planck Institute for Biological Cybernetics, Max Planck Society;

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Shmuel, A. (2008). Neuronal Correlates of Spontaneous Fluctuations in fMRI Signals in Monkey Visual Cortex: Implications for Functional Connectivity at Rest. Talk presented at 14th Annual Meeting of the Organization for Human Brain Mapping (HBM 2008). Melbourne, Australia. 2008-06-15 - 2008-06-19.


Cite as: http://hdl.handle.net/21.11116/0000-0003-92D7-5
Abstract
Previously, researchers who used fMRI, PET, optical imaging, and NIRS techniques to map the human brain regarded signal fluctuations at rest as noise.More recently, human imaging studies have discovered that cerebral hemodynamic signals during the non-stimulated, resting state carry meaningful information. These signals influence cortical evoked responses, and their variability correlates with perception and behavior. Moreover, functional networks of cortical areas manifest themselves through coherent fMRI signal fluctuations in the resting state. Therefore, it has been suggested that fluctuations in the resting state are an important principle of brain function. However, other reports expressed concerns with regard to the possibility that spontaneous fluctuations and functional connectivity in the resting state could be caused by irrelevant physiological fluctuations (e.g. respiration), vascular vaso-motion and imaging system noise. The degree in which spontaneous fluctuations in hemodynamic signals reflect fluctuations in the underlying neuronal activity is a topic of recent ongoing studies. The aim of the symposium is to bridge the gap between spontaneous fluctuations in fMRI signals and their underlying neuronal activity. The symposiumwill be opened by an overviewof studies on spontaneous fluctuations in fMRI signals and functional connectivity at rest. Three talkswill follow, focusing on spontaneous fluctuations in neurophysiological signals at rest, and howthey relate to fluctuations in hemodynamic signals. The symposiumwill describe the relationship between these signals via a large-scale global view of the cortex (EEG-fMRI), as well as in specific cortical regions via intra-cortical measurements in visual and motor areas. The neuronal correlates of spontaneous fluctuations in hemodynamic signals will be demonstrated by measurements of high spatial- and temporal resolution optical imaging using voltage sensitive dyes, neurophysiology and simultaneous neurophysiology with fMRI in animal models. These neurophysiological signals cover the range of membrane potentials, single and multi-unit activity, local field potentials, and mass neuronal activity.