OxTalks will soon move to the new Halo platform and will become 'Oxford Events.' There will be a need for an OxTalks freeze. This was previously planned for Friday 14th November – a new date will be shared as soon as it is available (full details will be available on the Staff Gateway).
In the meantime, the OxTalks site will remain active and events will continue to be published.
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Abstract: Dynamics of resting-state functional magnetic resonance imaging (fMRI) provide a new window onto the organizational principles of brain function. Using state-of-the-art sparsity-driven deconvolution [1,2], we extract innovation-driven co-activation patterns (iCAPs) from resting-state fMRI [3]. The iCAPs’ maps are spatially overlapping and their activity-inducing signals temporally overlapping. Decomposing resting-state fMRI in terms of iCAPs reveals the rich spatiotemporal structure of functional components that dynamically assemble known resting-state networks. The temporal overlap between iCAPs is substantial, which confirms crosstalk happening at the fMRI timescale; on average, three to four iCAPs occur simultaneously in specific combinations that are consistent with their behaviour profiles according to BrainMap. Intriguingly, in contrast to conventional connectivity analysis, which suggests a negative correlation between fluctuations in the default-mode network (DMN) and task-positive networks, we instead find evidence for two DMN-related iCAPs consisting the posterior cingulate cortex that differentially interact with the attention network. These findings illustrate how conventional correlational approaches might be misleading in terms of how task-positive and -negative networks interact, and suggest that more detailed, dynamical decompositions can give more accurate descriptions of functional components of spontaneous activity.
1] F. I. Karahanoglu, I. Bayram, D. Van De Ville, “A Signal Processing Approach to Generalized 1D Total Variation”, IEEE Transactions on Signal Processing, vol. 59, no. 11, pp. 5265-5274, Nov. 2011. [2] F. I. Karahanoglu, C. Caballero Gaudes, F. Lazeyras, D. Van De Ville, “Total Activation: FMRI Deconvolution through Spatio-Temporal Regularization”, NeuroImage, vol. 73, pp. 121-134, 2013. [3] F. I. Karahanoglu, D. Van De Ville, “Transient Brain Activity Disentangles fMRI Resting-date Dynamics in Terms of Spatially and Temporally Overlapping Networks”, Nature Communications, vol. 6, p. 7751, 2015.