Crcns: Deciphering The Laminar-Specific Functional Connectivity And Its Vascular And Neural Correlates

Dynamic brain signals provide key information that can be deciphered for a better understanding of brainfunction. Functional Magnetic Resonance Imaging (fMRI) has been developed to map not only the activitypattern but also functional connectivity in the whole brain. Although it has been over twenty years sincethe development of fMRI and the resting-state fMRI, the key challenge of fMRI-based signal interpretationremains to be the temporal and spatial resolution limit of the hemodynamic signal detected by fMRI. Inmost fMRI studies, the size of these voxels pre-determines the limits of the basic biological conclusion.With recent advancement leading to dramatic improvement in spatiotemporal resolution of MRI, thedynamic signal feature can be better clarified, which will significantly improve our understanding of brainfunction.In this proposal, a merged effort from three research groups is made to study the neural and vascularcorrelates of laminar-specific resting state fMRI signal fluctuation, which underlies the functional connectivitymapping in both human and animal models at varied brain states. Since the first report of large scale spatialsignal correlation in fMRI images (Biswal et al, 1995), the drastically improved spatiotemporal resolution ofhigh-field fMRI has revealed a number of key networks in the brain relevant to the default mode, attention,cognition, and sensorimotor connections. However, the millimeter size of voxels for resting-state and taskresults in fMRI signal dominated by large venous vessels. Although numerous studies have been designedto exclude signal contribution from veins, the neuronal correlates of resting-state and task fMRI signal hasbeen heavily linked to vascular contributions. It remains a challenge to disentangle the distinct neuronal andvascular contribution to fMRI signal fluctuation given the limited spatial and temporal resolution.As connectivity measures are increasingly being used, a number of groups are beginning to focus on mindbody interactions. In particular, connectivity measures, both local and global are being used in brain regionsincluding insula and thalamus to better understand more complex brain behavior interactions.