The analysis of alarge-scale database of neuroimaging activati on maps reveals a hierarchical correspondence betweenspontaneous and evoked brain activity patterns

PALMUCCI, MATÍAS; CAVANNA, FEDERICO; TAGLIAZUCCHI, ENZO

Mar del Plata

Congreso; XXXII Congress of the Argentine Society for Research in Neuroscience; 2017

Sociedad Argentina de Neurociencias

Since the seminal work by Biswal et al. (Biswal et al., 1995) - later expanded using multivariate methods by Beckmann and colleagues (Beckmann et al., 2005) - it is known that spontaneous brain activity recorded using fMRI presents a spatio-temporal organization consistent with well-defined neural s ystems. This correspondence was revealed for the fir st time by Smith and colleagues (Smith et al., 2009), who compared the independent components obtained from a database of fMRI task activation maps (ht tp://www.brainmap.org/) with those obtained from resting state fMRI data. The striking correspondence between both sets of components suggested that spontaneous brain activity recapitulates spatio-temporal pat terns that might be required for the rapid reaction to environmental demands. Here we investigate a database(http://neurosynth.org/) comprising 413429 maps obtained from 11406 studies. Combining graph-theoretical tools with modularization optimization algorithms, we performed a hierarchical clustering of these maps and observed task-positive and negative clusters at a coar se-level, which were then subdivided into maps associated with well-defined functions. In contrast with the work by Smith et al., the correspondence between task-derived maps and resting state networks was only manifest at an intermediate resolution. This result suggests that the wandering of brain activity around a hypothetical landscape of at tractor states can only occur at a certain spatio- temporal grain