Section: New Results

Accessibility of cortical networks during motor tasks

Participants : Mario Chavez [Correspondant] , Fabrizio de Vico Fallani, Miguel Valencia, Mario Chavez, Julio Artieda, Vito Latora, Donatella Mattia, Fabio Babiloni.

Recent findings suggest that the preparation and execution of voluntary self-paced movements are accompanied by the coordination of the oscillatory activities of distributed brain regions. We used electroencephalographic source imaging methods to estimate the cortical movement-related oscillatory activity during finger ex- tension movements. We applied network theory to investigate changes (expressed as differences from the baseline) in the connectivity structure of cortical networks related to the preparation and execution of the movement. We computed the topological accessibility of different cortical areas, measuring how well an area can be reached by the rest of the network. Analysis of cortical networks revealed specific agglomerates of cortical sources that become less accessible during the preparation and the execution of the finger movements. The observed changes neither could be explained by other measures based on geodesics or on multiple paths, nor by power changes in the cortical oscillations.

Figure 8. a) Averaged EMG and EEG (recorded at the postcentral region) signals of a subject during the execution of finger movements. Boxes define the three temporal epochs of EEG activity studied here: baseline (BASE), preparation (PRE) and execution period (EXE). Vertical dotted line indicates the movement onset. Examples of scalp and source-level networks obtained from one subject, at the frequency band Beta1, during the epoch EXE are shown in panels b) and c), respectively. Color map codes the number of connections.

Related publication: [3]