Spatial and temporal criticality in sensorimotor coordination

G SOLOVEY; K J MILLER; J G OJEMANN; M O MAGNASCO; G A CECCHI

Conferencia; Society for Neuroscience; 2011

The principle that neural systems are poised near a critical state is increasingly supported by experimental and theoretical results. In human subjects, however, most of our knowledge is based on functional magnetic resonance imaging (fMRI) studies, an indirect measurement of neuronal activity with poor temporal resolution. Electrocorticography (ECoG), on the other hand, provides a unique window into human brain activity. Each ECoG electrode records, with high temporal resolution, the global electrical potential that result from the sum of the local field potentials of ∼ 10^5 neurons. We present evidence of significant differences in the dynamically critical properties of the ECoG signals during the performance of finger movement versus rest, illustrating functional role of criticality in brain function. Dynamical criticality is inferred from an analysis of the eigenmodes of local autoregressive models fit to ECoG potentials. We also found that the human brain displays features of statistical criticality: avalanche-like behavior of ECoG potentials, with different variables displaying long range and heavy-tailed distributions. However, the differences between task conditions in the distribution of avalanche sizes is insigni!cant, in contrast to their dynamical stability, a !finding that supports our claim that criticality in the brain must be considered in a broader sense.