Coordinative task difficulty and behavioural errors are associated with increased long-range beta band synchronization.

The neural network and the task-dependence of (local) activity changes involved in bimanual coordination are well documented. However, much less is known about the functional connectivity within this neural network and its modulation according to manipulations of task complexity. Here, we assessed neural activity via high-density electroencephalography, focussing on changes of activity in the beta frequency band (~15-30Hz) across the motor network in 26 young adult participants (19-29 years old). We investigated how network connectivity was modulated with task difficulty and errors of performance during a bimanual visuomotor movement consisting of dial rotation according to three different ratios of speed: an isofrequency movement (1:1), a non-isofrequency movement with the right hand keeping the fast pace (1:3), and the converse ratio with the left hand keeping the fast pace (3:1). To quantify functional coupling, we determined neural synchronization which might be key for the timing of the activity within brain regions during task execution. Individual source activity with realistic head models was reconstructed at seven regions of interest including frontal and parietal areas, among which we estimated phase-based connectivity. Partial least squares analysis revealed a significant modulation of connectivity with task difficulty, and significant correlations between connectivity and errors in performance, in particular between sensorimotor cortices. Our findings suggest that modulation of long-range synchronization is instrumental for coping with increasing task demands in bimanual coordination.

Understanding bimanual coordination across small time scales from an electrophysiological perspective.

Bimanual movement involves a variety of coordinated functions, ranging from elementary patterns that are performed automatically to complex patterns that require practice to be performed skillfully. The neural dynamics accompanying these coordination patterns are complex and rapid. By means of electro- and magneto-encephalographic approaches, it has been possible to examine these dynamics during bimanual coordination with excellent temporal resolution, which complements other neuroimaging modalities with superb spatial resolution. This review focuses on EEG/MEG studies that unravel the processes involved in movement planning and execution, motor learning, and executive functions involved in task switching and dual tasking. Evidence is presented for a spatio-temporal reorganization of the neural networks within and between hemispheres to meet increased task difficulty demands, induced or spontaneous switches in coordination mode, or training-induced neuroplastic modulation in coordination dynamics. Future theoretical developments will benefit from the integration of research techniques unraveling neural activity at different time scales. Ultimately this work will contribute to a better understanding of how the human brain orchestrates complex behavior via the implementation of inter- and intra-hemispheric coordination networks.

La Clasificación Internacional de Funcionamiento (CIF) en la elaboración de un protocolo de evaluación del daño cerebral / The International Classification of Functioning, Disability and Health (ICF) for the development of an assessment protocol in brain injury patients

Objetivo: Evaluar la eficacia de un programa de rehabilitación individualizado (PRI) basado en la CIF en pacientes con accidentes cerebrovasculares (ACV). Material y método: Treinta y seis pacientes con ACV fueron sometidos a PRI según sus capacidades preservadas y factores personales. Se evaluaron distintas áreas antes y después del PRI con la CIF y otras escalas. Se compararon las diferentes puntuaciones pre y post tratamiento de las funciones corporales, actividades y factores ambientales. La muestra se dividió en dos grupos según tuvieran una evolución del ACV mayor o menor de cinco años. Resultados: Encontramos mejor respuesta al tratamiento en pacientes con menos de cinco años de evolución y obtuvimos correlaciones significativas entre actividades relacionadas con andar, hablar y comer, así como en aquellas funciones implicadas en dichas actividades como la recepción y expresión de lenguaje,las funciones integradoras del lenguaje y la fuerza muscular. Conclusión: Un PRI basado en la CIF como herramienta clínica mejora tanto el grado de funcionalidad como la autonomía en los pacientes con ACV (AU)

Objective: To evaluate the effectiveness of an individualized rehabilitation program (PRI) based on the ICF in stroke patients. Material and method: Thirty-six subjects with stroke underwent a PRI based on their preserved capacities, personal and contextual factors. Assessment was focused on different rehabilitation areas before and after the PRI with the CIF and different scales. We compared pre- and post-treatment punctuations regarding body functions, activities and environmental factors. The sample was divided into two groups: less than five and more than five years after stroke. Results: We observed greater treatment response in patients with less than five years of evolution. It was obtained high correlations between activity items related to walking, speaking and eating, as well as in body function items involved in reception and expression of language, integrative language functions and body muscles strength. Conclusion: The development of a PRI based on the ICF as a clinical tool improves the degree of functionality and autonomy in patients with stroke (AU)