Article

Studies with real-time functional magnetic resonance imaging (fMRI)
demonstrate that humans volitionally regulate hemodynamic signals from
circumscribed regions of the brain, leading to area-specific behavioral
consequences. Methods to better determine the nature of dynamic functional
interactions between different brain regions and plasticity due to
self-regulation training are still in development. OBJECTIVE: The authors
investigated changes in brain states while training 6 healthy participants to
self-regulate insular cortex by real-time fMRI feedback. METHOD: The authors used
multivariate pattern analysis to observe spatial pattern changes and a
multivariate Granger causality model to show changes in temporal interactions in
multiple brain areas over the course of 5 repeated scans per subject during
positive and negative emotional imagery with feedback about the level of insular
activation. RESULTS: Feedback training leads to more spatially focused
recruitment of areas relevant for learning and emotion. Effective connectivity
analysis reveals that initial training is associated with an increase in network
density; further training "prunes" presumably redundant connections and
"strengthens" relevant connections. CONCLUSIONS: The authors demonstrate the
application of multivariate methods for assessing cerebral reorganization during
the learning of volitional control of local brain activity. The findings provide
insight into mechanisms of training-induced learning techniques for
rehabilitation. The authors anticipate that future studies, specifically designed
with this hypothesis in mind, may be able to construct a universal index of
cerebral reorganization during skill learning based on multiple similar criteria
across various skilled tasks. These techniques may be able to discern recovery
from compensation, dose-response curves related to training, and ways to
determine whether rehabilitation training is actively engaging necessary
networks.

Langue : ANGLAIS