As continuation of earlier work in AMRI, further work on resting state fMRI signal fluctuations has identified at least 2 physiologic sources related to cardiac and respiratory cycles. It has been shown that proper accounting of theses source can substantially improve detection efficiency in fMRI. I addition, simultaneous EEG and fMRI studies have shown that a large part of the signal fluctuations have a neuronal contribution. This contribution is particularly strong during deep sleep, and was shown to correlate with EEG slow oscillations in many cortical regions. EEG slow oscillations have been recently shown to facilitate consolidation of memories in the cortex. AMRI showed, for the first time, the metabolic imprint of these oscillations. In the work on MRI anatomy, substantial progress has been made. Preliminary measurements on MS patients show unprecedented details in small, focal lesions. In normal subjects, substantial contrast variation was consistently seen across cortical layers, with specific patterns seen in motor cortex and primary visual cortex. For the Alzheimers project, 3 age-matched normal volunteers have been scanned so far with good results. With respect to the origins of MRI contrast, preliminary results from histological studies suggest that a large part of the intracortical variation in MRI relates to ferritin deposits.
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